LINKWAY S2 System Description

LinkWay™

SYSTEM DESCRIPTION

SDD00077_04 (August 23, 2007)

LinkWay™ System Description

Publication Information

Revision Number Date Released Comments

03 August 26, 2004 CO-016408

04 August 23, 2007 CO-041681

ViaSat, Inc.

Corporate Headquarters 6155 El Camino Real

Carlsbad, CA 92011-1699

Phone: (760) 476-2200

Fax: (760) 929-3941

Germantown, MD 20511 Seneca Meadows Parkway

Suite 200

Germantown, MD 20876

Phone: (240) 686-4400

Fax: (240) 686-4800

Duluth, GA 1725 Breckinridge Plaza

Duluth, GA 30096

Phone: (678) 924-2400

Fax: (678) 924-2480

SDD00077_04 (August 23, 2007) ViaSat Proprietary Page ii


TABLE OF CONTENTS LINKWAY® SYSTEM DESCRIPTION.................................................................................................. 1 Section 1—THE LINKWAY NETWORK ............................................................................................... 3

1.1 SUPPORT FOR A BROAD RANGE OF NETWORK TOPOLOGIES .............................. 4 1.2 NATIVE SUPPORT FOR PACKET-SWITCHING PROTOCOLS.................................... 6

IP SERVICE FEATURES.................................................................................................................... 6 FRAME RELAY SERVICE FEATURES ........................................................................................... 6 LEGACY PROTOCOL SUPPORT ..................................................................................................... 7

1.3 FLEXIBLE CONNECTIVITY AND SATELLITE ACCESS............................................... 7 1.4 EFFICIENT DEMAND-ASSIGNED BANDWIDTH MANAGEMENT ............................. 7 1.5 DIVERSE NETWORK APPLICATIONS.............................................................................. 7

VIRTUAL PRIVATE NETWORKS ................................................................................................... 8 PRIVATE CORPORATE NETWORKS ............................................................................................. 8 INTERNET SERVICE PROVIDERS.................................................................................................. 9 REAL-TIME DIGITAL VIDEO INTERNETWORKING .................................................................. 9 WIRELESS INTERCONNECTIVITY.............................................................................................. 10

1.6 LINKWAY’S SUBSTANTIAL BENEFITS.......................................................................... 10 DRAWBACKS OF OTHER TDMA SYSTEMS .............................................................................. 10

Section 2—LINKWAY NETWORK COMPONENTS ......................................................................... 13 2.1 THE LINKWAY INDOOR UNIT ......................................................................................... 13

THE LINKWAY MODEM................................................................................................................ 14 THE LINKWAY 2100 and LINKWAY.IP TERMINAL SPECIFICATIONS...................................... 16 THE LINKWAYS2 TERMINAL SPECIFICATIONS....................................................................... 19

2.2 THE LINKWAY OUTDOOR UNIT ..................................................................................... 21 THE LINKWAY RADIO FREQUENCY TERMINAL.................................................................... 21 THE LINKWAY ANTENNA............................................................................................................ 21

2.3 THE LINKWAY NETWORK CONTROL CENTER......................................................... 22 Section 3—LINKWAY NETWORK OPERATIONS............................................................................ 23

3.1 LINKWAY TDMA ARCHITECTURE ................................................................................ 23 FRAME FORMAT AND HIERARCHY........................................................................................... 23 LINKWAYS2 DVB-S2 Operation...................................................................................................... 25 SINGLE-BEAM AND MULTIPLE-BEAM OPERATION .............................................................. 26 SITE AND TERMINAL ADDRESSING.......................................................................................... 26 ACQUISITION AND SYNCHRONIZATION ................................................................................. 26

SDD00077_04 (August 23, 2007) ViaSat Proprietary Page iii


CLOCK MANAGEMENT................................................................................................................. 26

3.2 LINKWAY MANAGEMENT FEATURE............................................................................ 28 CONFIGURATION MANAGEMENT ............................................................................................. 28 ACQUISITION AND SYNCHRONIZATION CONTROL.............................................................. 28 BANDWIDTH MANAGEMENT ..................................................................................................... 29 FAULT PROTECTION ..................................................................................................................... 29 ACCOUNTING ................................................................................................................................. 29 PERFORMANCE AND ALARM MANAGEMENT........................................................................ 30 SECURITY MANAGEMENT........................................................................................................... 31

3.3 THE LINKWAY NETWORK MANAGEMENT WINDOWS........................................... 31 NMS ARCHITECTURE.................................................................................................................... 31 NMS WINDOW HIERARCHY ........................................................................................................ 32 NMS HOME PAGE ........................................................................................................................... 32 NETWORK STATUS........................................................................................................................ 33 BURST TIME PLAN......................................................................................................................... 34 SERVICE USAGE............................................................................................................................. 34 PERFORMANCE .............................................................................................................................. 35 DIAGNOSTIC TESTING.................................................................................................................. 35 ALARMS ........................................................................................................................................... 36 CONFIGURATION ........................................................................................................................... 36 SECURITY ........................................................................................................................................ 36 REMOTE ACCESS ........................................................................................................................... 37 SOFTWARE UPGRADES ................................................................................................................ 37

3.4 LINKWAY NETWORK PROTOCOLS AND SERVICES ................................................ 37 LINKWAY’S IP SERVICE ............................................................................................................... 37 LINKWAY’S FRAME RELAY SERVICE....................................................................................... 39

APPENDIX A—GLOSSARY .................................................................................................................. 41 APPENDIX B—LINKWAY RFT DESCRIPTION............................................................................... 57

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LIST OF EXHIBITS Exhibit 1- 1: A LinkWay Network ............................................................................................................ 4

Exhibit 1- 2: LinkWay—Three Topologies, One Platform ..................................................................... 4

Exhibit 1- 3: Single-Beam Configuration.................................................................................................. 5

Exhibit 1- 4: Multiple-Beam Configuration ............................................................................................. 6

Exhibit 1- 5: Virtual Private Network Application.................................................................................. 8

Exhibit 1- 6: Multiple-Services Private Corporation Network............................................................... 8

Exhibit 1- 7: Internet Service Provider Network ..................................................................................... 9

Exhibit 1- 8: Real-Time Surveillance Network ........................................................................................ 9

Exhibit 1- 9: Wireless Interconnect Application.................................................................................... 10

Exhibit 2- 1: LinkWay Network .............................................................................................................. 13

Exhibit 2- 2: Spares Required for 100-Node Network........................................................................... 13

Exhibit 2- 3: LinkWay Modulator and Demodulator............................................................................ 14

Exhibit 2- 4: LinkWay Modem Performance Table .............................................................................. 15

Exhibit 2- 5: LinkWay 2100 Front Panel................................................................................................ 16

Exhibit 2- 6: LinkWay 2100 Back Panel................................................................................................. 16

Exhibit 2- 7: Terminal Characteristics ................................................................................................... 16

Exhibit 2- 8: Terrestrial Interface Options for 2100.............................................................................. 17

Exhibit 2- 9: Terrestrial Interface Options for LinkWay.IP ................................................................. 17

Exhibit 2- 10: Rear Panel Functions—LinkWay 2100 and LinkWay.IP .............................................. 17

Exhibit 2-11: LinkWayS2 Front Panel ........................................................................................... 19

Exhibit 2-12: LinkWayS2 Back Panel....................................................................................................... 19

Exhibit 2-13: LinkWayS2 Terminal Characteristics............................................................................... 19

Exhibit 2-14: LinkWayS2 Terrestrial Interface Options ....................................................................... 20

Exhibit 2- 15: Rear Panel Functions— LinkWayS2................................................................................ 20

Exhibit 2- 16: Redundant NCC Elements............................................................................................... 22

Exhibit 3- 1: TDMA Frame Hierarchy ................................................................................................... 23

Exhibit 3- 2: Multi-Carrier TDMA Frame Alignment.......................................................................... 24

Exhibit 3- 3: LinkWay Burst Types ........................................................................................................ 24

Exhibit 3- 4: General TDMA Burst Structure ....................................................................................... 24

Exhibit 3- 5: DVB-S2 Operation.............................................................................................................. 25

Exhibit 3- 6: Single- and Multiple-Beam Configurations...................................................................... 26

Exhibit 3- 7: Clock-Generation Algorithm............................................................................................. 27

Exhibit 3- 8: Data Rates and Packet Sizes .............................................................................................. 27

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Exhibit 3- 9: Redundant NCC Options ................................................................................................... 29

Exhibit 3- 10: NMS Architecture............................................................................................................. 32

Exhibit 3- 11: NMS Window Hierarchy ................................................................................................ 32

Exhibit 3- 12: NMS Home Page ............................................................................................................... 33

Exhibit 3- 13: Terminal List..................................................................................................................... 33

Exhibit 3- 14: Burst Time Plan ................................................................................................................ 34

Exhibit 3- 15: Traffic Information .......................................................................................................... 34

Exhibit 3- 16: Service History .................................................................................................................. 35

Exhibit 3- 17: Service Connections.......................................................................................................... 35

Exhibit 3- 18: Diagnostic Testing............................................................................................................. 35

Exhibit 3- 19: Configuration Windows ................................................................................................... 36

Exhibit 3- 20: Frame Relay Service Compliance ................................................................................... 40

Exhibit B- 1: LinkWay RFT Transmit Specifications ........................................................................... 57

Exhibit B- 2: LinkWay RFT Receive Specifications.............................................................................. 57

Exhibit B- 3: LinkWay RFT Operating Characteristics ....................................................................... 58

SDD00077_04 (August 23, 2007) ViaSat Proprietary Page vi


LINKWAY® SYSTEM DESCRIPTION Satellite technology is often the preferred choice for a variety of telecommunications applications, such as:

Transaction-oriented or point-of-sale net-works.

IP multicasting and backbone connectivity.

Television broadcast distribution.

Basic voice and data communications where the terrestrial infrastructure is either insufficient or nonexistent.

It is now possible to address wideband multimedia applications with new advances in VSAT technol-ogy, thereby seamlessly extending terrestrial infra-structure over large geographic areas. LinkWay® provides native support for important telecommu-nications standards such as IP and Frame Relay.

LinkWay products provide a range of enterprise networking and telecommunications capabilities to fit almost every satellite and wireless network en-vironment. These products offer full-mesh, wide-band multi-service solutions on a single compre-hensive platform with multi-frequency TDMA sat-ellite air interface and packet transport services.

This document provides a high-level overview of the LinkWay network products to demonstrate how those products provide sensible solutions to chal-lenges in satellite networking. The three main sec-tions include:

Section 1—The LinkWay Network explains fea-tures and capabilities of the LinkWay networking equipment across a variety of applications.

Section 2—LinkWay Network Components de-scribes the physical elements of the LinkWay net-work site—the indoor unit, the outdoor unit, and the Network Control Center hardware.

Section 3—LinkWay Network Operations demon-strates how LinkWay uses TDMA to efficiently provide Frame Relay and Internet Protocol ser-vices.

This document also includes two appendices to aid in understanding the sophisticated utility of the LinkWay system in addressing satellite communi-cation solutions:

Appendix A—Terms & Acronyms is a useful guide to the LinkWay terminology.

Appendix B—LinkWay Radio Frequency Termi-nal Specifications describes the requirements for all LinkWay radio frequency terminals.

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Section 1—THE LINKWAY NETWORK LinkWay is a multi-carrier, multi-rate, time-division multiple access (TDMA), VSAT-like (very small aperture terminal) platform that works with conventional satellites. It provides seamless full-mesh connectivity for flexible, on-demand broadband corporate networking applications. The LinkWay system can support hundreds of low-cost terminals with small antennas. Single-hop connec-tivity is a standard feature without the need for an expensive central hub station.

The current LinkWay products include:

LinkWay 2100™—This terminal fully supports Frame Relay and IP, and uses an integrated radio frequency terminal. LinkWay 2100 is more cost effective for remote VSAT applications. This ter-minal uses an L-band RFT interface in support of broadband applications that span multiple satellite transponders.

LinkWay.IP™—This terminal fully supports IP. Packaged with smaller RFTs (2W, 4W, 5W) for star topologies, it is targeted for ISPs and corporate intranet applications. Unique IP software allows higher throughput IP applications.

LinkWayS2™—This terminal fully supports IP and frame relay. With an integral DVB-S2 receiver, LinkWayS2™ supports both mesh and broadband star IP networks, in addition to mesh frame relay networks. LinkWayS2™uses an L-band RFT inter-face in support of broadband applications that span multiple satellite transponders.

Using this family of LinkWay products, the system automatically allocates satellite bandwidth on an as needed, basis using dynamically measured traffic levels or on a fixed-assignment basis, if required.

In addition to efficient TDMA and automated bandwidth on demand (BoD), LinkWay eliminates the need for additional third-party networking equipment. This results in improved overall net-work reliability, lowered costs, and simplified in-tegration with terrestrial networks.

The LinkWay platform incorporates enhanced fea-tures providing a unique architecture that supports mesh, star, virtual star, and hybrid topologies. The product’s inherent flexibility allows individual VSAT locations to be configured as very low-cost remote terminals and economical high-capacity gateways. LinkWay broadband VSATs support multiple antenna and RF transceiver configurations with flexible carrier parameters that include vari-able bit-rates, power levels, and forward error cor-rection (FEC) settings for each carrier.

A LinkWay network has three basic parts:

The LinkWay terminal contains the satellite mo-dem and the necessary interfaces to provide Frame Relay and IP access.

The LinkWay outdoor unit (ODU) includes a ra-dio frequency terminal (RFT) and an antenna. The RFT consists of a solid state power amplifier (SSPA) and block up-converter (BUC). The termi-nal and ODU are connected by an interfacility link (IFL), which includes both a transmit (Tx) and a receive (Rx) cable. In addition, the LinkWay 2100, LinkWay.IP, and LinkWayS2 have the RFT inte-grated into the terminal, providing an L-band IF interface.

The heart of the LinkWay network is the Network Control Center (NCC), a Sun workstation that provides the management and control functions for all network terminals. The NCC is the platform for the LinkWay Network Management System (NMS) server. The NMS is the graphical user in-terface—accessed using a standard web browser, which the operator uses to configure the network and to request information from the NCC. The system supports NCC redundancy to increase net-work reliability.

Exhibit 1-1 illustrates four sites in a single net-work, with its NCC and NMS collocated with a LinkWay terminal and ODU combination, called a LinkWay site.



LINKWAY

(NMS Server)

LINKWAY

LINKWAY

LINKWAY

LINKWAY

LINKWAY

Internet

LAN

Internet

FrameRelay

LINKWAYNETWORK

Multi-CarrierTDMA

Customer Premises

IP

IP

Office Park Site

LAN IP

NCC

To NMSClients

via PSTNor PDN

FrameRelay

IPIF

Gateway Site

Customer Premises

Exhibit 1- 1: A LinkWay Network

Broadband VSATs like LinkWay are ideal for wideband multimedia applications encountered by multinational corporations, carriers, service pro-viders, virtual private network operators, and Internet service providers (ISPs). An effective broadband VSAT platform must provide the following capabilities in order to address today’s diverse multimedia networking applications, which are discussed below:

Support for a broad range of network topologies (Section 1.1).

Native support for packet- and circuit-switching protocols (Sec-tion 1.2).

Flexible connectivity and satellite access (Section 1.3).

Efficient demand-assigned bandwidth management (Section 1.4).

Diverse network applications (Section 1.5).

Substantial benefits (Section 1.6).

1.1 SUPPORT FOR A BROAD RANGE OF NETWORK TOPOLOGIES The three most popular and regularly encountered topologies include star (hub-and-spoke networks), mesh (any-to-any connectivity in one satellite hop), and virtual star (hybrid networks with multiple hub locations). These are illustrated in Exhibit 1-2:

A typical star network consists of a central hub location with many remotes supporting asymmetric outbound and inbound traffic requirements. Applications include application–specific interactive sys-tems in banking, retail, and other industrial sectors; PSTN network extensions; broadcast services; and Internet network extensions.

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LINKWAYLINKWAY

LINKWAYLINKWAY

Mesh LINKWAY

LINKWAYLINKWAY

LINKWAYLINKWAY

Star

LINKWAYLINKWAY

LINKWAYLINKWAY

Virtual Star(Hybrid)

Hub w/ 1 or moreLinkway Units

Exhibit 1- 2: LinkWay—Three Topologies, One Platform

ViaSat Proprietary SDD00077_04 (August 23, 2007)


NCC

NMS

NMS

MRT

TT3TT1

TT2

ODUODU

Site ASite B

AMRT

NCC

MRT Site

Exhibit 1- 3: Single-Beam Configuration

A mesh network consists of many terminals with one or two assigned to administer the network, no central hub location (although optional higher traf-fic gateways are possible), and support for any-to-any connectivity. Applications include telemedicine, corporate wide-area voice and data communications, LAN extensions and videoconferencing.

A virtual star or hybrid network consists of two or more hubs or gateways, and provides mesh con-nectivity between hubs, remote-to-multiple hub connectivity, and asymmetric data rates. Virtual star networks are essentially two-tiered topologies supporting high-traffic gateways with mesh con-nectivity to each other and small remote locations connected to the high-traffic gateways. Each tier requires links that provide fiber-like bit error ratio (BER) performance and asymmetric transmission rates. Typical applications include multinational corporate intranets, and service provider-operated virtual private networks.

LinkWay supports all three topologies, as well as:

Standard interfaces for packet-switched IP and frame relay networking applications.

Broadband data rates between 312 ksps and 5 Msps.

Demand-assigned allocation of bandwidth.

LinkWay is a powerful platform, supporting high-rate, multiple protocol services for high-end appli-cations, and affordable (small-aperture) remote terminals operating over low-rate carriers as well. The system operates seamlessly because larger VSAT sites can carrier-hop between large and

small carriers as required by changing connectivity requirements.

In a single-beam configuration, as illustrated in Exhibit 1-3, the NCC links all of the traffic termi-nals in the network through the master reference terminal (MRT). (In Exhibit 1-3, the arrows be-tween the NCC and MRT, and the NCC and AMRT, indicate redundancy.) In all cases, each LinkWay terminal is capable of serving both as a reference and a traffic terminal. (The MRT and AMRT, however, must reside at the same site as the NCC.)

For instance, the MRT in Exhibit 1-3 controls all geographic locations in the network. The NCC is collocated with the MRT, and both can be backed up by using an alternate master reference terminal (AMRT) and another NCC in a redundant configu-ration. NCC and MRT redundancy offers a one-time switchover from the active unit to the backup unit. If the configuration is multiple-beam, as in Exhibit 1-4, there is also a supporting reference terminal (SRT) to control the traffic terminals as-sociated with each satellite beam the MRT cannot see. The SRT relays NCC commands from the MRT.



NCC

TT

SRTMRT

TT

Exhibit 1- 4: Multiple-Beam Configuration

1.2 NATIVE SUPPORT FOR PACKET-SWITCHING PROTOCOLS Broadband VSATs need to provide native support for the most important and widely used packet-switching protocols. This allows seamless transi-tions between the terrestrial and the satellite net-works and reduces or eliminates the need for addi-tional third-party networking equipment. The

LinkWay indoor unit supports IP, and Frame Relay packet-switching protocols (Section 3.4 provides more detail about LinkWay and these two proto-cols.) Legacy protocols, such as X-25, are sup-ported over LinkWay via a connected router using a standard LinkWay interface.

IP SERVICE FEATURES

LinkWay dynamically routes IP packets using RIP-1 and RIP-2, protocols, and supports unicast and multicast services, as well as static and default routing. LinkWay also supports RFC 1490 for IP access over Frame Relay. A native 10BaseT Ethernet connection (100BaseT in LinkWayS2) simplifies connectivity between the terrestrial net-working equipment and the LinkWay terminal.

The LinkWay system manages the routing table for IP and dynamically assigns bandwidth as needed. When a point-to-multi-point burst is allocated for a

data stream, all network nodes designated a “con-trol group” receive the burst assignment.

LinkWay allows multicast traffic bandwidth classi-fied as real-time connections to be assigned a higher priority than unicast traffic. Additionally, the operator can manage the available bandwidth by specifying a unicast allocation factor.

A variety of applications are possible with native IP support, including data multicasting, video streaming, voice over IP, and LAN-to-LAN and WAN-to-LAN connections.

FRAME RELAY SERVICE FEATURES

Each Frame Relay connection can be configured for a specific quality-of-service requirement. LinkWay allocates bandwidth as required with a combination of static and dynamic TDMA bursts to the satellite.

The LinkWay terminal provides EIA-530/RS-449/V.35 synchronous serial interfaces via cables

to frame relay routers, access devices, and switches.

LinkWay supports RFC-1490, which allows IP packets to be extracted from Frame Relay frames over the serial interface.



LEGACY PROTOCOL SUPPORT

LinkWay supports legacy protocols such as SDLC, X.25, and 2-wire/4-wire analog voice requirements by combining the IP or Frame Relay interfaces

with external routers or Frame Relay access de-vices.

1.3 FLEXIBLE CONNECTIVITY AND SATELLITE ACCESS Broadband multimedia applications require flexi-ble network architectures and a variety of satellite connectivity options. LinkWay provides a multi-carrier (up to 256 carriers), multi-data-rate TDMA platform that can operate on one or more satellite transponders and supports flexible connectivity for any networking requirement.

The TDMA burst modem within the VSAT plat-form operates at symbol rates between 312 ksps and 5 Msps depending on the LinkWay platform to address a diverse range of broadband multimedia content. The transmit and receive data rates can be

set independently for asymmetric transmission ap-plications, such as those typically encountered with IP applications. In addition, robust satellite links are possible with fiber-like BER performance since each carrier is assigned a convolutional-Viterbi inner code and a Reed-Solomon outer code.

LinkWay is operable on any international or re-gional geosynchronous satellite system. Common frequency bands include C- and Ku-band; the sys-tem will also operate on bent-pipe Ka-band satel-lite systems.

1.4 EFFICIENT DEMAND-ASSIGNED BANDWIDTH MANAGEMENT The LinkWay system runs a central bandwidth management program in order to efficiently use space segment and provide high levels of end-user data throughput.

The bandwidth management function performs both fixed bandwidth allocation and dynamic bandwidth allocation (bandwidth on demand):

Fixed bandwidth allocation—Certain traffic cate-gories in Frame Relay require bandwidth to be al-located for the entire duration of the call. In these cases, bandwidth is allocated at call (or connec-tion) setup and remains allocated for the entire du-ration of the call. The bandwidth is de-allocated when the call ends (or the connection is torn down).

Dynamic bandwidth allocation (bandwidth on demand)—Every LinkWay terminal runs a Band-width Reporter program that continuously moni-tors the incoming user traffic. The dynamic band-width allocation function collects the

reports from all traffic terminals and periodically runs an algorithm to distribute available bandwidth resources fairly and efficiently using three levels of fairness:

Outgoing Fairness—All connections originating from a particular terminal compete for the terminal’s total trans-mission capacity in a fair manner.

Incoming Fairness—All connections terminating at a particular terminal compete for the terminal’s total re-ceive capacity in a fair manner.

System Fairness—All connections in the entire network compete for the to-tal system capacity in a fair manner.

This algorithm provides bandwidth alloca-tion in response to changing incoming user traffic rates in a dynamic manner.

1.5 DIVERSE NETWORK APPLICATIONS

LinkWay is particularly well-suited to the diverse topologies needed for today’s wideband networks. Service providers and multinational corporations

can economically establish mesh, star, or virtual star networks using a single platform. This is im-portant for service providers, because:



Mesh networks support teleconferencing require-ments.

Star networks support Internet access and data dis-tribution.

Virtual star networks support corporate data intra-nets connecting remote offices to headquarters, factories, and MIS centers.

Popular broadband VSAT network examples, de-

scribed below, include:

Virtual private networks.

Private corporate networks.

Internet service providers.

Real-time digital video internetworking.

Wireless interconnectivity.

Disaster recovery.

VIRTUAL PRIVATE NETWORKS

Frame Relay/IP

LINKWAY

Company C

LINKWAY

LINKWAY

LINKWAY

LINKWAY

Company C

Company C

Company B

Company BCompany A

Company A

Company B

Company A

Exhibit 1- 5: Virtual Private Network Application

A virtual private network service provider, as illus-trated in Exhibit 1-5, can establish virtual IP or Frame Relay connections over satellites using broadband terminals as entry points for client loca-tions. The operator’s investment includes installing an NCC and leasing partial transponder space on any commercially available C- or Ku-band geo-stationary satellite. The operator takes advantage of the bursty nature of client traffic and demand-assigned bandwidth to reuse the same transponder resources among a pool of clients. Because most applications do not require a full-time dedicated data pipe, the network resources are made avail-able only for active applications.

The service provider bills customers for actual us-age. Smaller customers (fewer than 10-20 sites) can interconnect branch or remote offices without major investments in bandwidth and network man-agement infrastructure. The service provider’s monthly bill to the end customer includes the

equipment lease, installation expenses, and band-

width use.

PRIVATE CORPORATE NETWORKS

iceax

Private multinational corporate networks en-counter a wide variety of applications, such as intranets and LAN extensions. Typical require-ments include file and image distribution, in-ventory control, video conferencing over FR and IP, e-mail, database backup, voice-over-digital PBXs, and voice over IP. Because Link-Way is configurable for any network topology, corporations can affordably provide broadband content to and from multiple locations. Exhibit 1-6 illustrates a multiple-services corporate network.

Page 8 of 58 ViaSa

Vo/FPABX

PSTN

LANVideo

PABX

Router

Video

PSTN

LAN

LAN

TCP/IP

PABXLINKWAY

LINKWAY

LINKWAY

Exhibit 1- 6: Multiple-Services Private CorporationNetwork

t Proprietary SDD00077_04 (August 23, 2007)


INTERNET SERVICE PROVIDERS

LINKW AY

LINKWAY

LINKW AY

Server

PSTN

LINKWAY

LINKWAY

ContentProvider

4 Mbps250 Kbps

Gateway

ISP ServicePOP-to-POP Connectivity(E-mail, Voice, LAN)

POP #1

POP#25

POP #50

Exhibit 1- 7: Internet Service Provider Network

Because LinkWay networks support asymmetric traffic applications, they are ideal for Internet ser-vice providers (ISPs). An asymmetric circuit con-sists of high-rate and low-rate connections. Exhibit 1-7 illustrates an ISP application using multiple high-rate connections and several low-rate connec-tions. The high-rate connection broadcasts IP con-tent to all point-of-presence (POP) locations, each of which serves a large community of dial-in users. Low-rate connections are shared among POPs to transport requests to the content-provider. The low-rate connections can also be used for adminis-trative traffic (such as e-mail, technical support, reports, request for spare equipment, and voice

applications) among the individual POPs in a sin-gle satellite hop.

REAL-TIME DIGITAL VIDEO INTER-NETWORKING

Video teleconferencing, telemedicine, and video surveillance are growing applications for broad-band VSATs, and all require transporting real-time digital video over IP. For example, the digital video surveillance network shown in Exhibit 1-8 comprises several distinct user groups. These are combined to form one network of many remote

surveillance sites, each monitoring highway traffic.

Each remote surveillance site broadcasts digital video signals to gateway locations using IP multi-casting at a user-specified data rate. The data rates and the specific user groups can be programmed for video transmissions. All other network com-munications, such as group-to-group connectivity,

can be implemented with IP unicasting on de-mand.

Satellite Dish

Sensor

Video

AsymmetricCommunications

Exhibit 1- 8 Real-Time Surveillance Network



WIRELESS INTERCONNECTIVITY

LinkWay can accommodate cellular or base station connectivity over the satellite by using VoIP or VoFR call routing, and high-speed TDMA carriers. Typical base stations require T1/E1 connections to the central office on demand. A broadband VSAT facilitates the rapid extension of a country’s wire-less telephony infrastructure to smaller cities and rural areas that either lack E1/T1 infrastructure or need to augment their E1/T1 capacity. A wireless interconnection application is illustrated in Exhibit 1-9.

1.6 LINKWAY’S SUBSTANTIAL BNetworks based on LinkWay™ products have clear advantages over the existing VSAT systems in the market. The benefits of LinkWay networks in-clude:

LinkWay networks use a hub-less architec-ture.

Multi-protocol support enables easy migra-tion to emerging applications.

LinkWay networks support asymmetric traffic requirements.

LinkWay networks support both full-mesh and star topologies on a single platform in a single hop.

LinkWay’s unique patented dynamic band-width-on-demand (BoD) algorithm dis-tributes network bandwidth among many sites effectively and efficiently as needed.

LinkWay networks support wideband traf-fic on demand.

DRAWBACKS OF OTHER TDMA SYSTEM

As compared with LinkWay, other TDMA systems have substantial drawbacks:

Other TDMA systems cannot support high-speed IP-unicast, IP-multicast, and frame relay applica-tions on a single platform, which drastically limits future migration choices.

Page 10 of 58 ViaSat Pr

MTS

BS BS

LINKWAY

PSTN

LINKWAY LINKWAY

Exhibit 1- 9: Wireless Interconnect Application

ENEFITS In situations where the wideband content is pro-vided from various destinations, LinkWay net-works support multiple gateway network architec-tures without a hub.

LinkWay networks support multimedia applica-tions through standard native, Frame Relay, and IP interfaces. This enables LinkWay terminals to in-terface seamlessly with existing terrestrial net-works and to improve overall network reliability by minimizing the need for additional third-party devices.

LinkWay networks offer flexible satellite carrier definition configuration to support variance in the transponder and remote antenna. This includes the ability to define a transponder frequency offset, if known and defined, to enhance the tracking Rx capability for the terminals. In addition, the ability to define signal power level on carrier basis sup-ports smaller and larger antennas in the same net-work.

S

The multi-board design of the indoor units in these systems makes maintenance and sparing costly and decreases reliability and efficiency.

oprietary SDD00077_04 (August 23, 2007)


The other TDMA systems have limited carrier-hopping capability for the asymmetric topologies and applications required by Internet service pro-viders.

Limited modulation and coding capabilities of these systems combine to increase their bandwidth consumption, space segment cost, and station size.

The fixed burst of these systems result in frag-mented space segment, lower bandwidth effi-ciency, and longer response time.

Because these systems do not support cross-strapped transponders and inclined orbit satellites, they have limited connectivity and growth poten-tial.

The bandwidth-on-demand capabilities of these systems are inefficient.

These systems support multi-carrier-hopping re-quirements among no more than a few carriers, which severely limits true wideband networking applications.

These systems require a separate network man-agement system for every eight to ten carriers, which results in bandwidth fragmentation and complicated operation.

Other TDMA systems have limited carrier throughputs.



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Section 2—LINKWAY NETWORK COMPONENTS A LinkWay network consists of LinkWay sites managed by a Network Control Center (NCC) workstation at one of the sites. The LinkWay hardware includes:

The terminal—the upper left portion of Exhibit 2-1—the speci-fications for which are described in Section 2.1 below.

The outdoor unit, or ODU, consists of the radio frequency terminal (RFT) and antenna. Their specifications are listed in Section 2.2 and Appendices B and C.

The NCC includes a Sun workstationTheir specifications are detailed in Sect

LinkWay is an extremely reliable systble in Exhibit 2-2 shows the mean ti

Exhibit 2- 2: SPAR

Replaceable Units

Remote Terminal

Remote ODU

Single NCC

Terrestrial Interface Adapter (TIA)

*Based on an accumulatedpercent and assuming fa

2.1 THE LINKWAY INDOThe LinkWay terminals are housed rack-mountable packages with L-bandlinks (IFL) to radio frequency termioperating in C-, Ku-, or Ka-band.

The modulator output and demodulatobe set as indicated in Exhibit 2-3. To oformance, LinkWay performs automsetting of the internal front-end attenu

SDD00077_04 (August 23, 2007)

LINKWAY

EthernetHub

PC with ApplicationSoftware

BUC SSPA

AMPController

IF Input from LNB

L-Band IF Outputto ODU

10 B

ase

T

SSPA 48VDC

WR75

Tx IFLTNC (10MHz)(12/15vdc)

LNB

WR75 vdc)

Rx IFL L-Band (950)-1640 MHz)15 vdc "F" Female

Exhibit 2- 1: LinkWay Network

and a PC. ion 2.3.

em. The ta-me between

failures (MTBF) for the network elements and, consequently, how many spares are required in a 100-node LinkWay network.

ES REQUIRED FOR 100-NODE NETWORK

MTBF (Hours)

Number of Units

Number of Spares*

70,000 100 6

50,000 100 7

40,000 1 1

100,000 100 5

Poisson distribution model using an availability of 99.9 iled units are replaced in 40 days.

OR UNIT in compact

interfacility nals (RFTs)

r input can ptimize per-atic coarse ator. Based

on the satellite system and geographic location, the LinkWay terminal can be deployed with a variety of RFTs, ranging from 1.2-m/2-Watt Ku-band units to 3.8-m/60-Watt C-band units.

The LinkWay contains a TDMA burst modem, TDMA frame controller, and terrestrial traffic in-terfaces.

Up to three physical interfaces can be activated on

ViaSat Proprietary Page 13 of 58


the LinkWay 2100 unit—the Internet Protocol (IP) interface is built-in, and the customer can select up to two Frame Relay (V.35, RS-449, RS-530), inter-faces as optional interfaces. The LinkWay.IP ter-minal supports only IP. The LinkWayS2 has built-in interfaces for IP and FR, and can support two op-tional plug-in interface cards.

Exhibit 2- 3: LinkWay Modulator and Demodulator

Modulator Out-put

Demodula-tor Input

LinkWay 2100 & LinkWay.IP

-5 to –25 dBm in ½ dBm steps

-35 to –75 dBm

LinkWayS2 0 to -30 dBm in ½ dBm steps

-35 to -75 dBm

THE LINKWAY MODEM

LinkWay incorporates a multi-carrier, multi-rate, time-division multiple access (TDMA) modem. Each carrier in the LinkWay network can be con-figured with different speeds and forward error correction (FEC) rates. Larger carriers increase terminal throughput, but also increase outdoor unit (ODU) power and size requirements. Smaller car-riers limit connectivity to star or partial-mesh to-pologies, but also reduce capital investment per remote terminal. With the exception of the ODU size, the system administrator can modify the con-figuration at any time.

As many as 256 carriers can be supported in a LinkWay network. Initially, however, only one carrier is required for each network. Additional carriers can be added as the network traffic in-creases. All carriers in a transponder can be auto-matically shared among the users on demand. As-signment of terminals to carriers is performed dy-namically by the Network Control Center (NCC) collocated with one terminal.

LinkWay 2100, LinkWay.IP supports the following modem TDMA symbol rates:

312.5 ksps

625 ksps

1.25 Msps

2.5 Msps

5 Msps

LinkWayS2 supports the following TDMA symbol rates:

312.5 ksps

625 ksps

1.25 Msps

2.5 Msps

5 Msps (optional)

This multi-rate feature accommodates various net-work applications and antenna sizes. Regardless of the selected modulation and coding scheme, carrier bandwidth occupancy remains constant. Modula-tion and coding selection affect power require-ments, as well as user information throughput. Therefore, it is common to configure the traffic bursts with QPSK modulation to increase user in-formation throughput. The NCC automatically configures modulation and coding for each burst. The transmit and receive side of the modem can operate and hop asymmetrically and independ-ently. This feature is ideal for Internet Service Pro-vider (ISP) point-of presence (POP) applications, or corporate networks with asymmetric traffic ar-chitecture.

The LinkWayS2, in addition to incor-porating a multi-carrier, multi-rate, time-division multiple access (TDMA) modem, incorporates an integrated DVB-S2 receiver which provides high-speed download capability from a central site, as well as interoperability with ViaSat’ s LinkStar system.

LinkWay-S2’s DVB-S2 receiver uses EN 302 307 compliant coding, so that operators may use LinkWay-S2 with a standard EN 302 307 DVB-S2 modu-lator and IP encapsulator, or with Vi-aSat’s LinkStar-S2 hub.

The LinkWay Modem Performance Table in Ex-hibit 2-4 provides a performance summary.



LinkWay2100, LinkWay.IP, and LinkWayS2 use Viterbi FEC with concatenated Reed Solomon (236, 216) coding. The FEC is configurable by carrier.

Turbo product code is optional for the LinkWayS2.

Modulation for the LinkWay 2100 and Link-Way.IP is QPSK.

The LinkWayS2 uses QPSK modulation in the standard configuration. 8PSK modulation is op-tional for the LinkWayS2.

The LinkWay modem has a rolloff factor of 0.3; the carrier spacing factor is 1 + (roll-off) = 1.3. Thus, the allocated bandwidth is the symbol rate x 1.3.

The IF looped Eb/No performance for BER = 10-8 is listed in the following table. Additional margin (typically 0.4 to 0.8 dB) above these values should be allocated to account for RF looped performance. The LinkWayS2 operates up to 2.5 Msps as stan-dard. An option is available for operation up to 5.0 Msps.

Exhibit 2-4: LINKWAY MODEM PERFORMANCE TABLE

Carrier Symbol

Rate

FEC Satellite Link Bit

Rate

Eb/No

Ksps Kbps dB5000 1/2 4590.2 4.65000 2/3 6120.2 5.25000 3/4 6885.2 6.15000 7/8 8032.8 7.82500 1/2 2295.1 4.62500 2/3 3060.1 5.22500 3/4 3442.6 6.12500 7/8 4016.4 7.81250 1/2 1147.5 4.61250 2/3 1530.1 5.21250 3/4 1721.3 6.11250 7/8 2008.2 7.8625 1/2 573.8 4.9625 2/3 765.0 5.5625 3/4 860.7 6.4625 7/8 1004.1 8.1

312.5 1/2 286.9 5.2312.5 2/3 382.5 5.8312.5 3/4 430.3 6.7312.5 7/8 502.0 8.4



THE LINKWAY 2100 and LINKWAY.IP TERMINAL SPECIFICATIONS

The tables and figures below detail the LinkWay 2100 and IP terminal specifications:

Exhibit 2- 5: LinkWay 2100 Front Panel

Exhibit 2-5 displays the LinkWay 2100 front panel.

Exhibit 2-6 displays the LinkWay 2100 back panel with optional TIAs installed.

Exhibit 2-7 details the LinkWay terminal’s ba-sic characteristics.

Exhibit 2-8 details LinkWay’s terrestrial inter-face options for LinkWay 2100.

Exhibit 2-9 details LinkWay’s terrestrial inter-face options for LinkWay.IP.

Exhibit 2-10 displays rear panel functions for the LinkWay 2100 and LinkWay.IP.

Exhibit 2- 6: LinkWay 2100 Back Panel

Exhibit 2- 7: TERMINAL CHARACTERISTICS

LinkWay 2100 and LinkWay.IP Dimensions • 8.9 cm/3.5” (h) x 43.8 cm/17.25” (w) x 36.8.4 cm/14.5” (d) and mount-

able in a standard 19” rack Weight • 5 kg/11 lbs

Temperature • Operating: 0° to +40°C • Storage: 0° to +70 °C

Relative Humidity • Operating: 0 to 95% • Storage: 0 to 95%

Power supply • 50/60 Hz; auto-range: 100 VAC to 240 VAC

Power consumption • 80VA without ODU

Fuse • 3 Amps at 264 V

Certification • CE, UL, and FCC



Exhibit 2- 8: TERRESTRIAL INTERFACE OPTIONS FOR 2100

Ethernet Serial Synchronous

Protocols

IP: RIP-1, RIP-2

Frame Relay, RFC 1490

Maximum Data Rate 3 Mbps 2 Mbps

Clock Rate 10 Mbps 64 to 2,048 kbps

Standards

RFC 1058

RFC 1490

RFC 1112

EIA/TIA-449

EIA/TIA-530

V.35

Physical Interface 10BaseT, IEEE 802.3

RS-449/RS-422

RS-530/RS-422

V.35

Connectors 6-pin RJ-45 • 26-pin SCSI • RS-449 37-pin, D-type • RS-530 25-pin, D-type • V.35

Exhibit 2- 9: TERRESTRIAL INTERFACE OPTIONS FOR LINKWAY.IP

LinkWay.IP Ethernet

Protocols IP, RIP-1, RIP-2

Maximum Data Rate 3 Mbps duplex

Clock Rate 10 Mbps

Standards RFC 1058, RFC 1112

Physical Interface 10BaseT, IEEE 802.3

Connectors 8-pin RJ-45



Exhibit 2- 10: REAR PANEL FUNCTIONS—LINKWAY 2100 and LINKWAY.IP

Function Rear Panel Label Specification

Power supply • 50/60 Hz • Auto-range—100 VAC to 240 VAC

ODU IF connec-tions

IF INPUT TO ODU

IF OUTPUT FROM ODU

• Tx—950-1525 MHz (L band), 50 Ohm, Type N female

• Rx—950-1750 MHz (L band), 75 Ohm, Type F female

• TVRO—950-1750MHz (L band), 75 Ohm, Type F female

Craft Interface CONSOLE • 4-Pin RJ-11 Jack—RJ-11 to DB25 converter cable supplied. Supports RS-232, external mo-dems.

LAN Interface 10BaseT • 8-Pin RJ-45 Jack—IEEE 802.3 compatible. 10BaseT physical interface

Network Clock In-terface (10 MHz)

EXT REF • 50 Ω BNC—1V peak-to-peak sinusoidal clock waveform input

Interface 1 No Label

Left Slot

• Supports 1 LinkWay Interface Card—,Frame Relay, (not available on LinkWay.IP)


Right Slot

• Supports 1 LinkWay Interface Card—, Frame Relay, (not available on LinkWay.IP)



THE LINKWAYS2 TERMINAL SPECIFICATIONS

The tables and figures below detail the Link-WayS2 terminal specifications:

Exhibit 2- 11: LinkWayS2 Front Panel

Exhibit 2-11 displays the LinkWayS2 front pan-el.

Exhibit 2-12 displays the LinkWayS2 back panel.

Exhibit 2-13 details the LinkWayS2 terminal’s basic characteristics.

Exhibit 2-14 details terrestrial interface options for LinkWayS2.

Exhibit 2-15 displays rear panel functions for the LinkWayS2 .

Tx Out, 75 , Type-F Jack

10 MHz Ref., 50 , BNC Jack

10/100 MHz Ethernet, RJ-45

RS-232 Console Port, RJ-11

Form C AlarmAuxiliary ODU Power

Rx In, 75 , Type-F Jack

USB Port

Ground Stud

IEC Power Connector w/ Switch

Expansion Interface 2

Expansion Interface 1

Frame Relay, 26 pin SCSI-2

Exhibit 2-12: LINKWAYS2 BACK PANEL

Exhibit 2- 13: LINKWAYS2 TERMINAL CHARACTERISTICS

LinkWayS2P Dimensions • 4.4 cm/1.73” (h) x 43.1 cm/17” (w) x 39.6 cm/15.6” (d) and mountable in

a standard 19” rack Weight • 3.4 kg/7.5 lbs

Temperature • Operating: 0° to +50°C • Storage: 0° to +70 °C

Relative Humidity • Operating: 0 to 95% • Storage: 0 to 95%

Power supply • 50/60 Hz; auto-range: 100 VAC to 240 VAC

Power consumption • 55 VA without ODU

Fuse • 3 Amps at 264 V

Certification • CE, UL, and FCC



Exhibit 2- 14: LINKWAYS2TERRESTRIAL INTERFACE OPTIONS

Ethernet Serial Synchronous

Protocols

IP: RIP-1, RIP-2 Frame Relay, RFC 1490

Maximum Data Rate

Variable 2.048 Mbps

Clock Rate 10/100BT, FDX 64 to 2,048 kbps

Standards

RFC 1058

RFC 1490

RFC 1112

EIA/TIA-449

EIA/TIA-530

V.35

Physical Interface

10/100BaseT, IEEE 802.3

RS-449/RS-422

RS-530/RS-422

V.35

Connectors 6-pin RJ-45 • 26-pin SCSI

Exhibit 2- 15: REAR PANEL FUNCTIONS—LINKWAYS2

Function Rear Panel Label Specification

Power supply • 50/60 Hz • Auto-range—100 VAC to 240 VAC

ODU IF connec-tions

IF INPUT TO ODU

IF OUTPUT FROM ODU

• Tx—950-1750 MHz (L band), 75 Ohm, Type F female

• Rx—950-1750 MHz (L band), 75 Ohm, Type F female

Craft Interface CONSOLE • 4-Pin RJ-11 Jack—RJ-11 to DB25 converter cable supplied. Supports RS-232, external mo-dems.

LAN Interface 10BaseT

100BaseT (s2)

• 8-Pin RJ-45 Jack—IEEE 802.3 compatible. 10/100BaseT physical interface

Multi-Function BNC Connector

EXT REF • 50 Ω BNC—Programmable 10MHz clock refer-ence input/output; SORF/SOTF trigger


Left Slot

• Supports 1 LinkWayS2 Interface Card PMC Expansion Slot


Right Slot

• Supports 1 LinkWayS2 Interface Card—, PMC Expansion Slot



2.2 THE LINKWAY OUTDOOR UNIT A LinkWay network will function efficiently with a variety of radio frequency terminals (RFTs) and antennas, including customer-owned equipment.

The specifications for the LinkWay RFT are briefly described in The LinkWay Radio Fre-quency Terminal section below and detailed in Appendix B.

The specifications for the LinkWay antenna are briefly described in The LinkWay Antenna section below.

THE LINKWAY RADIO FREQUENCY TERMINAL

The Ku-Band radio frequency terminals (RFTs) for LinkWay 2100, LinkWay.IP, and LinkWayS2 can be configured for 2-, 4-, 8-, 16-, or 25-Watt operation and the C-Band transceivers for 5-, 10-, 20-, 40-, and 60-Watt operation:

In LinkWay 2100, LinkWay.IP, and LinkWayS2 the RFT interface is integrated into the terminal for a substantial cost savings to the customer.

A monitoring feature verifies system status and isolates faults in the field-replaceable unit.

The RFT, housed in a weatherized enclosure, can be either mounted on or adjacent to the antenna feed support and has the following circuitry:

Transmit and receive RF converters.

Transmit RF power amplifier.

Summary alarm circuitry.

Configurations employ a standard BUC integrated with an SSPA or booster amplifier. The SSPA is a

galium arsenide field effect transistor (GaAs FET) based for highly linear operation. Both the gain and the detected power are calibrated over tem-perature and frequency. Control data for these functions are stored in lookup tables.

All ViaSat-supplied LNBs (C and Ku-Band) are phase-locked (PLL) and externally referenced to a 10 MHz signal. The LinkWay terminal generates the 10 MHz reference signal. The externally locked PLL LNBs ensure proper acquisition of TDMA bursts at all carrier symbol rates. Internally locked LNBs cannot ensure successful burst acquisition and should not be used.

Appendix B describes the RFT in some detail—The LinkWay’s RFT dimensions are detailed in Exhibit B-1 and the transmit and receive specifica-tions in Exhibits B-2 and B-3, respectively. Ex-hibit B-4 details the LinkWay RFT’s operating characteristics.

THE LINKWAY ANTENNA

The LinkWay network is typically supplied with a 1.2-m, 1.8-m, 2.4-m, or 3.8-m antenna system type approved by EUTELSAT or INTELSAT. Link-Way can also be used with most customer-supplied antennas, as well as specially configured antennas.

1.2-m Antenna System—For both C-band and Ku-band. The latter includes the EU-TELSAT-type approved option of long-focal-length.

1.8-m Antenna System—For both C-band and Ku-band.

1.8-m Antenna System—INTELSAT-type-approved for C-band and EUTEL-SAT-type-approved for Ku-band.

2.4-m Antenna System—For both C-band and Ku-band.

2.4-m Antenna System—INTELSAT-type-approved for C-band and EUTEL-SAT-type-approved for Ku-band.

3.8-m Antenna System—For linear and circular C-band and for Ku-band.



2.3 THE LINKWAY NETWORK CONTROL CENTER The NCC performs overall management and con-trol of the LinkWay network. Network configura-tion is defined at the NCC and automatically dis-tributed to the terminals. The NCC can be config-ured in a redundant or non-redundant architecture, either at the same site or at geographically sepa-rated sites.

A single LinkWay traffic terminal is always desig-nated as Master Reference Terminal (MRT) and connected to the NCC using an Ethernet interface. The NCC then communicates with other LinkWay

terminals through the MRT via the satellite link. Operators located remotely can log on to the NCC using PCs (or Macs) with Web browsers. This re-mote client—the Network Management System (NMS)—is the operator’s interface to the network configuration and status screens. The NCC is a hosted on a Sun workstation. Exhibit 2-16 illus-trates a redundant NCC setup. A non-redundant situation uses a single Sun workstation, external modem, and universal power supply.

PC Computer

Sun WorkstationNCC

External ModemUniversalPower Supply

LINKWAY

LINKWAY

Sun WorkstationAssociated

NCC

External ModemUniversalPower Supply

Linkway MRT

Linkway AMRT

Network Control Center Components

(Locally Redundant)

PSTN

PSTN

EthernetSwitch

Exhibit 2- 16: Redundant NCC Elements



Section 3—LINKWAY NETWORK OPERATIONS This final section ties together four elements in order to complete this high-level description of the LinkWay network:

Section 3.1 describes LinkWay’s TDMA architec-ture.

Section 3.2 describes LinkWay network manage-ment features.

Section 3.3 illustrates LinkWay network manage-ment windows.

Section 3.4 details LinkWay protocols and ser-vices.

3.1 LINKWAY TDMA ARCHITECTURE In order to access the space segment, LinkWay uses time division multiple access (TDMA) tech-niques. Frame Format and Hierarchy describes the frame format and hierarchy that LinkWay uses.

LinkWay can function in either Single-Beam or Multiple-Beam Operation, and can efficiently ac-commodate very large or small networks. The

manner in which LinkWay handles all these alter-natives is described in Site and Terminal Address-ing, while LinkWay’s acquisition and synchroniza-tion techniques are outlined in Acquisition and Synchronization. LinkWay’s clock management is described in Clock Management. Packet and Cir-cuit Transport Services outlines LinkWay packet and circuit transport services.

FRAME FORMAT AND HIERARCHY

Reference

SOF Frame Period EOF

SOMF

SOCF

Frame 1 Frame 2 Frame 3 Frame nFrame n-1

MF 2MF 1 MF 3 MF m-1 MF m

Control Frame Period

Multiframe Period

Exhibit 3- 1: TDMA Frame Hierarchy

LinkWay employs a hierarchical frame structure composed of frames, multiframes, and control frames as illustrated in Exhibit 3-1.

TDMA Frame Structure A TDMA frame is the basic periodic interval of time during which a terminal transmits or receives one or more bursts. LinkWay frame duration has a nominal value of 27 ms. Every frame boundary is delineated by a start-of-frame (SOF) instant—a point relative to the position of the beginning of the first symbol of the reference burst in the frame. Each reference burst frame is identified numerically by a frame identifier.

As Exhibit 3-2 illustrates, each carrier in a multi-carrier operation transports a TDMA frame that is time aligned with all other carriers’ frames on SOF, start of multiframe (SOMF), and start of control frame (SOCF). A multiframe is the duration of N consecutive frames. The nominal value for N is 8. Multiframe boundaries are deline-ated by an (SOMF) instant encoded in the frame identifier.

LinkWay transmits and receives bursts on speci-

fied frames of the multiframe.

A control frame is the duration of M consecutive frames. The nominal value for M is 128. Control frame boundaries are delineated by an SOCF in-stant encoded in the frame identifier. LinkWay transmits and receives bursts on specified frames of the control frame.



Exhibit 3- 3: LinkWay BURST TYPES

Burst Type

Transmitting Terminal

Type Purpose

Reference (RB)

Reference • Conveys outbound NCC signaling

• Conveys timing feedback data to traffic terminals

• Establishes receive timing Signaling (SB)

Traffic • Conveys inbound traffic terminal signaling

Acquisition (AB)

Traffic • Conveys transmit response message

• Used to acquire traffic ter-minal transmit timing

Control (CB)

Traffic • Conveys traffic terminal status report

• Used to maintain traffic ter-minal Transmit timing

Traffic (TB)

Reference and Traffic

• Conveys circuit and packet data

SOF SOMF SOCF

SOF SOMF SOCF

Carrier 1

Carrier 2

Carrier N•••

Exhibit 3- 2: Multi-Carrier TDMA Frame

Alignment

TDMA Burst Structure In LinkWay, the burst is the high-level unit of transmission, with multiple burst types providing efficient space-segment use. Exhibit 3-3 itemizes the burst types.

Bursts are composed of several fields. Exhibit 3-4 displays the burst structure and its relationship to frames and carriers. The burst structure has the following elements:

The carrier and bit timing recovery (CBTR) data pattern aids receiving modems in obtaining carrier and symbol clock acquisition. The CBTR consists of 128 consecutive symbols of alternating binary 1's and 0's. The CBTR beginning defines the burst position in the frame.

The unique word (UW) data pattern aids receiving modems in locating the first symbol of the first channel in the data field. The UW consists of 48 consecutive symbols. Reference bursts have a UW that differs from non-reference bursts.

RB SB CB AB TB TB

TDMA Frame

Carrier 1

TB

RBSB TB TB TBTB TB

CBTR UW Channel 0 Channel 1 Channel C GuardBurst

Data Bits

Circuit Packet

Packet 1 RSChannel RS Packet 2 Packet P

Carrier 2

Exhibit 3- 4: General TDMA Burst Structure (Channel structure for illustrative purposes only—circuit and packet

data are never on the same burst)



Channel structure—Bursts can carry either 64-kbps circuit or packet data within their channels. Packet bursts may have up to 8 channels. Circuit bursts are either 64-kbps data or 8-kbps com-pressed voice. Circuit-data channels are simply filled with encoded data. Packet-data channels con-tain many packets of varying length. To facilitate error detection and depending on correction, Reed-

Solomon check bytes are included in both circuit- and packet-data channels.

Guard time—Every burst is defined in the frame with guard space to prevent transmit burst timing errors from resulting in burst overlap and loss of data. Each terminal’s bursts are controlled in order to limit timing variations at the satellite to ± 1/2 guard time.

LINKWAYS2 DVB-S2 Operation

LinkWayS2 incorporates a built-in DVB-S2 re-ceiver, in addition to its TDMA modulator and TDMA demodulator, which shares a common receive input with the TDMA demodulator. The LinkWayS2 integrated DVB-S2 receiver/decoder can receive a broadband IP data stream from a DVB-S2 hub, providing efficient broadband star connectivity to a central data source while si-multaneously providing full-mesh capability.

LinkWayS2, for example, can support band-width- intensive IP applications such as stream-ing video over the DVB-S2 link while support-ing intrinsically mesh applications such as VoIP over mesh TDMA. Also, LinkWayS2 is interop-erable with ViaSat’s LinkStarS2 system, provid-ing a universal, flexible networking solution.

Exhibit 3- 5: DVB-S2 Operation in LinkWayS2

DVB-S2 HUB

LinkWay-S2 combines full-mesh networking with broad-band DVB-S2 downlink in one integrated package.

LinkWayS2

LinkWayS2

LinkWayS2



SINGLE-BEAM AND MULTIPLE-BEAM OPERATION

LinkWay is designed for both single-beam and multiple-beam operation. Exhibit 3-6 depicts a simple example of each. As shown in the figure, in the single-beam case, all terminals have transmit and receive access to all carriers assigned to the system. The MRT directly supports all terminals. In the multiple-beam case, terminals have transmit access to one set of carriers and receive access to another. The MRT supports terminals in Beam 2 and the supporting reference terminal (SRT) sup-ports traffic terminals in Beam 1.

BEAM 1 BEAM 2

CARRIERS

SRT

TT1NCC/NMS TT2

MRT

MULTIPLE-BEAM CONFIGURATION

NCC/NMS

CARRIERS

SINGLE-BEAM CONFIGURATION

TT1

TT2

MRT

Exhibit 3- 6: Single- and Multiple-Beam Configurations

SITE AND TERMINAL ADDRESSING

The LinkWay site and terminal addressing scheme efficiently accommodates a wide range of network configurations and is designed to support thou-sands of sites. Each site can have multiple termi-nals. In addition to individual terminals, the system can also address sites and groups of sites. This ad-dressing scheme provides for very large networks without penalizing small ones.

Although only one terminal will be designated as the MRT in a LinkWay network, each LinkWay terminal can perform as both reference and traffic terminal. The NCC dynamically assigns the refer-ence terminal function, which simplifies configura-tion, maintenance, and upgrade procedures, while increasing the system’s flexibility.

ACQUISITION AND SYNCHRONIZATION

Because the Doppler motion of the satellite and oscillator drift normally cause timing variations, maintaining synchronization is critical to the error-free operation of any network. LinkWay terminals use TDMA acquisition and synchronization proce-dures to establish and maintain burst synchroniza-tion.

LinkWay procedures enable new terminals to join the network quickly. Typically, a terminal will en-

ter the network within 30 seconds of power up. A network of 100 terminals ready to enter the net-work typically completes entry within 10 minutes. As the network grows, or if faster entry is desired, multiple acquisition bursts can be defined. Termi-nals can enter the network at approximately the rate of 10 per minute per acquisition burst.

CLOCK MANAGEMENT

To minimize timing error in the system, each LinkWay terminal automatically monitors and ad-justs its direct digital synthesizer (DDS) to match that of its MRT or supporting reference terminal.

To further minimize timing error, an industry-standard, highly accurate external clock source can be connected to the reference terminal as an op-tion. The reference terminal’s DDS tracks the ex-ternal clock in frequency and phase, while all other

terminals continue to track the reference terminal’s DDS. This is a cost-effective method for highly accurate timing throughout the system. Without an external clock source, the DDS is accurate to 1 part in 107. An accurate external clock typically raises accuracy to 1 part in 1011.



LinkWay terminal interfaces accept data timed to the terrestrial data-receive clock and use the terres-trial data-receive clock in transmitting data to the terrestrial network

In order to generate accurate clocks in its distrib-uted TDMA system, LinkWay uses a distributed

algorithm that requires an accurate clock source at the TDMA terminal. (See Exhibit 3-7.) The local clocks of all other terminals are phase locked to the reference terminal’s clock.

Clock Correction

ru rd tutd

Satellite

GPSDiscOSC

Ref Clock(20 MHz)

FreqCounter(error)

TX/RXcorrections

Clock Algorithm

Reference Terminal

VCXO

TX/RXTiming

Terr/ModemClock Ref(doppler free) Freq

Counter(error)

TX/RXcorrections

Clock Algorithm

Traffic Terminal

VCXO

TX/RXTiming

Terr/ModemClock Ref(doppler free)

Exhibit 3- 7: Clock-Generation Algorithm



3.2 LINKWAY MANAGEMENT FEATURE The NCC is the central control for the entire LinkWay network. Hosted on a Sun workstation, the NCC software runs as a single application process and performs the following functions:

Configuration Management.

Acquisition and Synchronization Control.

Bandwidth Management.

Fault Management.

Accounting.

Performance and Alarm Management.

Security Management.

CONFIGURATION MANAGEMENT

The NCC stores all configuration data for the en-tire LinkWay network. Each configuration data file is similar to a file (or a relation) in a regular data-base management system. The NCC software reads the configuration data into RAM at startup; this RAM copy is used during network operation. The files are written to only when configuration data changes—for example, additions and deletions to existing data.

The NCC Configuration Management function interfaces with the Java-based NMS to add, delete, or modify the configuration data.

At terminal startup—and upon any configuration changes—the NCC downloads configuration data. Should the configuration data change, the NCC sends modifications to the terminals.

ACQUISITION AND SYNCHRONIZATION CONTROL

The NCC controls acquisition and synchronization of the LinkWay network. Upon startup, the NCC establishes contact with the MRT (and SRT) and commands it to initiate reference station acquisi-tion and synchronization. The reference station starts transmitting the reference burst. In loopback-beam operation, the reference station hears its own transmission in order to achieve synchronization. In multiple-beam operation, the MRT hears the SRT’s reference burst and vice-versa in order to achieve synchronization.

After the MRT (and SRT) achieves synchroniza-tion, the NCC initiates the acquisition and syn-chronization procedure for traffic terminals in the system, using the reference terminals as a relay to

communicate with the terminals. Traffic terminals are commanded to transmit a sequence of acquisi-tion bursts, whose arrival time and frequency are measured by the MRT. Using these measurements, the NCC sends back frequency and timing correc-tions to the traffic terminals, and they are then ready to carry user traffic.

After initial acquisition and synchronization, traffic terminals periodically transmit control bursts, whose timing and frequency are measured by the MRT or SRT. Using these measurements, the NCC sends back further frequency and timing correc-tions to the terminals. These corrections keep the terminals synchronized with satellite movements.



BANDWIDTH MANAGEMENT

Please see the earlier section, “1.4 EFFI-CIENT DEMAND-ASSIGNED BANDWIDTH

MANAGEMENT” for more detail.

FAULT PROTECTION

LinkWay has three levels of fault protection:

System faults are handled through the NMS and its alarm functions. A: Non-redundant B: Locally redundant

C: Geographically redundant

Satellite

Sun Station

LINKWAY 2000 LINKWAY 2000

LINKWAY 2000

Sun Station

LINKWAY 2000

Sun Station Sun Station

Sun Station

Exhibit 3- 8: Redundant NCC Options

Terminal faults are minimized using redun-dant-terminal operation for terrestrial interfaces (see, for illustration, Exhibit 1-3).

Network faults are minimized in two ways: (a) redundant NCC configuration and (b) re-dundant MRT configuration.

The NCC can be configured as either locally or geographically redundant (see Exhibit 3-8 for several options). In a geographically redundant configuration, the NCC functions are passed to a standby NCC on a backup Sun workstation located at a different site.

In redundant MRT cases, the NCC monitors its connection to the MRT and AMRT. When it detects that the MRT is not responding, the NCC automatically switches the reference station func-tions to the alternate master reference terminal. This switch-over mechanism allows continuous

operation of the TDMA network, even when the MRT fails.

The LinkWay NCC and MRT redundancy scheme offers a single rollover from active to passive unit, ensuring no unscheduled disruption in network synchronization.

ACCOUNTING

The NCC accounting function generates account-ing reports for all user IP and frame relay connec-tions A resource utilization record is written at connection startup and shutdown.

The accounting management subsystem’s architec-ture consists of an accounting manager module at each terminal and the NCC communicating over the reliable packet transport protocol.

The NCC accounting manager receives accounting records from all terminal accounting managers and stores them in accounting files. There is one ac-counting file per service per accounting session, with each accounting session being a 24-hour pe-riod.

Each call has a unique call ID that appears in all accounting records written for it. This ID holds across terminal and NCC resets. Intermediate re-cords are generated at the end of every accounting session for calls lasting more than a day. If a ter-minal fails, appropriate records are generated for ongoing calls. Call beginning and end times are noted in Greenwich Mean Time (GMT), although accounting sessions may end at midnight GMT or local time.

For more detail, refer to document item # 1025156, “LinkWay Accounting Features” available on the ViaSat Extranet Web site.



PERFORMANCE AND ALARM MANAGEMENT

The performance management function is useful in monitoring a terminal’s health and for diagnosing problems. It enables the NMS operator to view transmit and receive burst data and to collect per-formance data—BER and link statistics and IP traffic—from individual terminals. The NMS op-erator can also assess service statistics from Frame Relay, or IP connections. The NCC collects data for each burst containing the selected connection. Data are gathered for channel access control transmissions to and from the satellite, and for the terrestrial interfaces by link and connection.

The operator can collect performance statistics from individual terminals for monitoring the health of a particular terminal and for diagnosing prob-lems. Various fault alarms are collected from the terminals and distributed to the NMS for display on the operator screen. Some of the important pa-rameters monitored are:

Statistics for each receive burst.

Accumulated statistics for each transmit burst.

Accumulated statistics on a per destination basis (e.g., number of packets sent, allo-cated packet bandwidth, average number of bytes per sec).

Packets dropped at a node.

Packets forwarded at a node.

Throughput on the link.

The NCC monitors the following informa-tion for each terminal:

Terminal ID.

Terminal type—MRT, SRT, or TT.

State—Up/down

Number of times the terminal has ac-quired.

Number of acquisition commands sent to the terminal.

Number of status request messages sent to the terminal.

Number of status response messages re-ceived from the terminal.

Number of reports received from the ter-minal.

The following statistics are maintained on a per-port basis:

Current port status—Up or down.

Loopback condition detected—Yes or no.

Data packets received for transmission.

Data bytes received for transmission.

Data packets sent to the user.

Data bytes sent to the user.

Number of signaling packets received.

Number of status inquiry packets received.

Number of status packets received.

Number of signaling packets sent.

Number of status inquiry packets sent.

Number of status packets sent.

User procedure signaling errors, e.g., mes-sage loss, sequence number, invalid header.

Number of times user procedures declared the channel inactive.

Network procedure signaling errors (mes-sage loss, sequence number, invalid header etc.).

Number of times network procedures de-clared the channel inactive.

The operator can send diagnostic commands to a terminal or the NCC. The major diagnostic func-tions that can be executed via the NMS are:

Verifying TDMA performance by displaying burst statistics. Along with the number of data segments transmitted on each burst, the system reports burst ID and the number of detects, misses, Viterbi cor-rections, and cyclic redundancy check (CRC) er-rors.



Verifying Frame Relay performance through the Frame Relay connection control process in a ter-minal, which handles making and breaking con-nections within the LinkWay network.

Verifying IP performance by providing IP statis-tics for each terminal in the network with IP traffic.

The alarm management function collects informa-tion regarding various terrestrial interface alarms from the terminals and distributes it to the NMS for display on the operator’s screen. The system

displays information for all active alarms in the system and identifies failures at the interface card level. Alarms are sent only for equipment or inter-face failure. Service performance or BER levels will not trigger any alarms

In addition, whenever a terminal goes down, or the NMS loses its connection to the NCC, the NMS sounds a continuous beep alarm, and displays the Beep Alarm window. The NMS operator must ac-knowledge the alarm to turn off the beep.

SECURITY MANAGEMENT

The NCC maintains NMS operator login and password information as part of the configuration data and uses this information to authenticate op-erators trying to log into the system. The system has three levels of security:

Full Access—Allows the NMS operator to view and modify all configurable databases.

Read-Only Access—Allows the NMS operator to view only the configuration data. This privilege can be further specified to limit access to configu-ration data of one or a set of terminals.

Restricted Access—Allows the NMS operator to read only portions of the network that have been specified.

3.3 THE LINKWAY NETWORK MANAGEMENT WINDOWS The LinkWay NMS is a web-based, platform-independent Java application that provides central network management functionality. Any number of NMS client systems, running on any platform us-ing any Java-capable Web browser can retrieve

data from and deliver information to the NCC. This creates a significant cost advantage over other network management systems requiring a specific platform.

NMS ARCHITECTURE

The NMS-NCC interface follows the general architecture in Exhibit 3-9. The NMS consists of a web browser application that opens an HTTP connection to the web server running on the NCC host machine. The NCC machine is a Sun

workstation running a UNIX application. Run-ning independent from the NCC—but on this same Sun workstation—is an off-the-shelf web server. The web server manages incoming HTTP socket connection requests.



Sun

SPARCsta tion

Sun

SPARCstatio nNCC (WWW)

HTTP NMS consists of aplatform-independent

web-browser applicaiton

NCC includes a web server that provides anNMS applet via an http URL (descriptor file)

to any and all web client requests

Exhibit 3- 9: NMS Architecture

NMS WINDOW HIERARCHY

Exhibit 3-10 illustrates the hierarchy of NMS windows.

IP ISDN FrameRelay ATM

Configuration

NMS Home Page

Performance Monitoring

Alarms

Network Configuration Site Configuration

ODUConfiguration

ServiceConfiguration

Accounting/Billing

Call Managemnt

Search NetworkMap

SystemLog

Network Status

Diagnostic Testing

TerminalConfiguration

Service Connections

Exhibit 3- 10: NMS Window Hierarchy

NMS HOME PAGE

A map showing the status of the LinkWay network automatically appears as the NMS Home Page. (See Exhibit 3-11.) From this page, the operator can explore the LinkWay network. The home page enables the NMS operator to view sites and termi-nals geographically and readily obtain status and configuration information. When a detailed map is available, zoom selection displays a larger map of

the area and shows the terminal icons. Map graph-ics are enhanced for each customer’s locations.

The home page map shows the location of sites in the network and updates the associated icons when terminal status changes:

Green indicates a terminal is up.

Red indicates a terminal is down.



Exhibit 3- 11: NMS Home Page

Black indicates the site has no configured termi-nals.

Yellow indicates (in multi-terminal sites) some terminals are up and some are down.

Operators can also navigate to site, terminal, and protocol configuration screens after selecting a particular site or terminal on the map.

NETWORK STATUS

Clicking Network Status brings up detailed in-formation on terminal status and network events. For example, the Terminal List tab lists all cur-rently configured terminals, as well as the cur-rent status and alarm state of each. (See Exhibit 3-12.)

Exhibit 3- 12: Terminal List

The Event Log tab, on the other hand, lists all major network events, each of which is time and date stamped. Initially, the system retrieves the last 10 log entries; the operator can request more entries as desired.



BURST TIME PLAN

The Burst Time Plan window displays the cur-rent burst allocation for each type of burst. (See Exhibit 3-13.) The system dynamically updates this display as bandwidth is allocated, enabling the operator to graphically view the bandwidth-on-demand feature in real time—the bursts ap-pear and disappear as the NCC monitors the LinkWay network and allocates and de-allocates bandwidth based on user traffic requirements

.

Exhibit 3- 13: Burst Time Plan

SERVICE USAGE

Detailed accounting and billing information is maintained on the NCC Sun workstation. These resource utilization records (or call detail records) are stored in an easily im-ported format.

Exhibit 3- 14: Traffic Information

The operator can generate graphic representations of traffic information for calls through any site. (See Exhibit 3-14.) Usage can be displayed by day, week, month or other specified time interval. The operator uses the Service History button on the home page to bring up lists of all service connections. (See Exhibit 3-15.)



Exhibit 3- 15: Service History

PERFORMANCE

In a manner similar to service history, the operator can view detailed information on active connec-tions, physical interfaces, and TDMA transmit and receive statistics. The Performance button brings up a list of all service connections. (See Exhibit 3-16.) Selecting any terminal or interface and press-ing The Get Stats button displays details about any current call for service to or from any site.

Exhibit 3- 16: Service ConnectionsDIAGNOSTIC TESTING

Diagnostic testing enables the operator to execute and view the results of diagnostic commands. (See Exhibit 3-17.) These commands can be executed on the NCC or from any terminal.

Exhibit 3- 17: Diagnostic Testing



ALARMS

The operator can view and analyze all the system’s active terrestrial interface alarms with the click of a button. In addition, the system issues an audible

beep alarm and displays a message window should a terminal go down or the NMS lose connection with the NCC.

CONFIGURATION

Beginning with the windows illustrated in Exhibit 3-18, the operator configures all network, site, and

service parameters for the network.

Exhibit 3- 18: Configuration Windows

SECURITY

The LinkWay NMS implements several levels of security. The first is enforced by the web server. Clients requesting access are checked for valid IP addresses and domain names. When a valid client address has been identified, the web server then prompts for operator authentication. After authenticating the operator’s identity, the web server downloads the HTML files and app-let bytecode to run on the local client machine.

The second level of security is implemented at the applet level. The bytecode is compressed and signed with a certificate—a password-protected, encrypted data file that ensures the identity of the operator. This certificate allows each NMS setup to independently allow or disallow various operations to the NMS.

Finally, once the applet is downloaded and run-ning, it opens a TCP socket connection to the NCC. The applet then prompts the operator for a LinkWay user ID and password, and the NCC verifies.

After verifying the operator’s ID, the system performs several levels of checks and filtering:

The operator’s ID is first checked against the NMS client address to see if the operator has connected from a valid host.

The operator is then identified with the appro-priate security level and set of NMS functions the operator is allowed to access.



Based on this security level, NMS operations are limited to the information pertaining to the

LinkWay sites designated as accessible to that particular operator.

REMOTE ACCESS

Because the NMS is a web-based application run-ning on any Java-compatible browser, operators can access the NMS from any location on any PC

with an IP connection to the Sun workstation run-ning the NCC.

SOFTWARE UPGRADES

Because all NMS software is web-based, it is con-tained within a Java applet maintained by the web server on the NCC host machine. This enables automatic software updating. Customers automati-

cally receive and install all software updates for their NMS without any local installation proce-dures.

3.4 LINKWAY NETWORK PROTOCOLS AND SERVICES While the Internet Protocol (IP) is built into all LinkWay terminals, the LinkWay 2100 and Link-WayS2 terminals can also support Frame Relay, terrestrial interface protocols. The LinkWay 2100

uses a plug-in terrestrial Frame Relay interface card, while the LinkWayS2 has one built-in frame relay interface. The following sections detail these two LinkWay services.

LINKWAY’S IP SERVICE

The LinkWay system supports IP networking using an RJ-45 Ethernet LAN port as the physical inter-face.

Internet protocols are the means by which a router gains information about the network. Routers de-termine the best path or route to get to the destina-tion. The purpose of a router is effectively to sup-ply efficient traffic flow and management of end-to-end packet flow. For IP, a LinkWay terminal acts as a network router and routes each IP packet toward its destination. As a router, LinkWay broadcasts advertisement packets (signifying its presence) to all network nodes and communicates with the other routers regarding their network con-nections, the cost of connections, and traffic load levels. The LinkWay network supports most of the standard routing protocols, including the Routing Information Protocol, both RIP-1 and RIP-2.

LinkWay uses dynamic routing, which automati-cally reconfigures the routing table. Unlike a typi-cal IP network, which supports only best-effort service, LinkWay also allows configuring mini-mum-guaranteed-packet throughput between two sites. LinkWay also supports multicast routing, where a source terminal can send a single trans-mission to multiple terminals at the same time.

Convergence—reconfiguring the routing tables—must occur quickly before traffic terminals with incorrect information misroute data packets into dead ends. To solve this, the LinkWay master ref-erence terminal (MRT) acts as an integrated router and exchanges information about the network's topology with all traffic terminals in the network. Using its bandwidth-on-demand function, the MRT also continually re-balances the traffic load and regularly updates a map of the entire network, in-cluding all the devices operating at or below its own protocol level. Using this network map, the MRT ascertains the current status of all possible paths to destinations and selects the best method—usually the fastest—of transporting the packet.

Routing Information Protocol (RIP) Because of the popularity of TCP/IP throughout the world in today's networks, many vendors' products have RIP implementations. LinkWay, which supports RIP-1 and RIP-2, can handle nearly all of these implementations. For example,

The major features of RIP include:

Using the user datagram protocol for broadcasting routing tables.



Using a count of each router or gateway

the packet needs to pass through—called a hop count—to measure the distance be-tween source and destination. The maxi-mum number of hops allowed is 15. A network is considered unreachable if it has 16 or more hops.

Updates to routing tables are sent by routers every 30 seconds.

Routes are timed out in 180 seconds unless an update for that path has arrived.

RIP operates with two types of user devices: active and passive. Active users advertise their routes via a broadcast over their networks, while passive us-ers listen and update their routes based on the RIP information, but do not advertise routes.

An active RIP user—such as LinkWay—advertises routes about every 30 seconds. Within a RIP broadcast is a paired listing of every IP network the sender of the RIP message can reach and the distance, in hops, to that network. Within RIP, a router is defined to be one hop away from directly connected networks, two hops from networks that are reachable from one other router, and so on.

IP Service Provisioning Provisioning IP service involves two steps:

1. Submitting the LinkWay terminal IP ad-dress and subnet mask, and the desired routing protocol (RIP1, RIP2) to the NMS.

2. Defining any permanent virtual circuits and related CIR values to be used within the network.

Once these choices are entered, the NMS auto-matically downloads the configuration to the NCC, which sends it to all relevant terminals, and the LinkWay system is ready for IP traffic.

IP Service Operations The traffic terminal coordinates with the NCC via a connection defined between the MRT and the traffic terminal. When a traffic requirement exists,

the traffic terminal sends a connection request to the NCC. The NCC then checks both sending and receiving terminals to verify they are active (UP on the network). It also checks the IP interfaces to verify they are active. Any defined CIR for the connection will be used first for sending the trans-mission. The NCC allocates additional bandwidth on an as-available basis, using bandwidth-on-demand algorithms should more bandwidth be re-quired.

Multicast traffic uses the same process as unicast (single point-to-point transmission), with the mul-ticast connection defining which terminals will receive the transmission. The NCC allocates bandwidth on demand to the multicast transmis-sion, giving network priority to multicast traffic over unicast. Receiving terminals accept the transmission only if a client has requested it. Both features ensure efficient bandwidth use in the LinkWay network.

IP Special Features Each LinkWay IP port acts as an interface of a vir-tual satellite-based router. IP packets entering one LinkWay interface are automatically routed by IP address, and transported to the destination Link-Way IP interface.

Quality of service is maintained via differential services compatible prioritization with six transmit queues. Application-triggered bandwidth allocation ensures bandwidth is allocated to match specific customer applications, such as voice or video.

Onboard TCP acceleration (available only on LinkWayS2 unit) removes satellite delay-induced throughput limits. Built-in IP header compression reduces bandwidth required for VoIP.

IP multicast feature enables one LinkWay site to simultaneously communicate with multiple other LinkWay sites – perfect for multi-party video con-ferencing or distance learning.

All LinkWay terminals are IPSec transparent and can be used with peripheral IP encryption devices.



LINKWAY’S FRAME RELAY SERVICE

LinkWay’s Frame Relay access is supported at the UNI/NNI connection level with ANSI or ITU local management interface (LMI) for access manage-ment and is compliant with the ITU and ANSI standards listed in Exhibit 3-19.

A serial synchronous port is the physical layer in-terface, using V.35, RS-449, or EIA-530 connec-tors with DTE or DCE options and internal or ex-ternal clock rates up to 2 Mbps.

LinkWay performs frame switching and forward-ing on a data link connection identifier (DLCI) basis. Multiple connections (DLCIs) can be provi-sioned to multiple destinations. Each connection is configured with bi-directional committed informa-tion rate (CIR), committed burst size (Bc), and ex-cess burst size (Be) as QoS parameters. These are soft configurable on a per-virtual circuit basis, which allows the operator to tailor the virtual cir-cuit to requirements:

Fixed-based CIR virtual circuits can be provi-sioned with finite CIR, matching Bc, and zero Be. The entire bandwidth is pre-allocated before the virtual circuit is activated. This type of virtual cir-cuit is more suitable for constant bit rate real-time traffic like voice and leased-line applications.

Usage-based CIR can be provisioned by reserving part of the bandwidth as CIR and allocating the rest on demand using non-zero Bc. This type of virtual circuit is suitable for real-time variable rate applications like video conferencing or video streaming.

Exhibit 3- 19: FRAME RELAY SERVICE COMPLIANCE

Standards ITU-T ANSI

Service Description I.233 T1.606

Core Aspects Q.922 Annex A T1.618

Signaling for VCs Q.933 Annex A T1.617 Annex D

Zero CIR virtual circuit is intended for non time-critical e-mail, file transfer, and applications like web-browsing. With this service there is no guar-antee of sustained bandwidth as the system does not pre-allocate any bandwidth. Bandwidth gets allocated as traffic increases. If the system has to drop traffic, this type of traffic is first to be dis-carded.

Asymmetric CIR allows different CIRs to be pro-vided in each direction of the virtual circuit. It is useful for applications such as file transfer that require more traffic going in one direction than the other.

Frame Relay over LinkWay gives users the cost

savings of a shared service with the quality of ser-vice equal to a private line. Dynamic bandwidth management enhances the inherent advantage of Frame Relay’s statistical multiplexing.

Frame Relay Service Provisioning Provisioning Frame Relay service is extremely simple using the NMS and involves two steps:

1. Configuring the serial interface for Frame Relay service—Select the rate of transmission, clock source, and type of in-terface (RS 449, V.35, EIA 530). Specify the local management interface (LMI) type—ANSI or ITU—and other related pa-rameters.

2. Configuring the connection—Select both source and destination sites and interfaces, and other related QoS parameters (e.g., CIR and Bc).

Once these choices are made, the NMS automati-cally downloads the configuration to the NCC, which sends it to all relevant terminals, and the LinkWay system is ready for Frame Relay traffic.

Frame Relay Service Operation In Frame Relay, the LinkWay terminal coordinates establishing the virtual circuit with the NCC. It

waits for its local interface to be active before sending the connection request to the NCC. (“Ac-tive” means that LMI between the interface and the connected user equipment is up and running.)

The NCC waits for a connection request from both sides of the connection to arrive before bandwidth allocation. Bandwidth equivalent to the configured value of CIR is allocated and both terminals are informed of this resource allocation.



The concerned terminals report the virtual channel as New and Active at their LMI interface using connection signaling information elements.

Following this, traffic on the connection begins. Incoming traffic is policed for the traffic agree-ment, with frames in excess of CIR tagged as non confirming frames. Each connection has its own queue of frames for transmission over the satellite

interface. LinkWay employs its patented band-width-on-demand algorithms to allocate more bandwidth, when available, for transporting traffic in excess of CIR.

In the event an interface or terminal goes down, the connection at the other end is reported as inactive, and bandwidth is de-allocated. When the interface recovers, the connection is re-established.




APPENDIX A—GLOSSARY

TERM MEANING

AB See “Acquisition burst (AB).”

ABR See “Available bit rate (ABR).”

Access line A communications line interconnecting a Frame Relay, ATM, or IP-compatible device (data terminal equipment—DTE) to a frame-relay, ATM, or IP switch respectively (data communications equipment—DCE).

Access rate (AR) The access channel’s data rate—The maximum rate at which the end user can in-ject data into a frame-relay network.

ACM See “Address complete message (ACM).”

Acquisition burst (AB) A LinkWay traffic terminal (TT) uses an AB while trying to achieve transmit syn-chronization with the master reference terminal (MRT).

Address complete message (ACM)

A message sent in backward direction indicating that all the address signals re-quired for routing the call to the called party have been received.

Address resolution protocol (ARP)

The Internet Protocol used to map dynamic Internet addresses to physical (hard-ware) addresses on local area networks. (“Dynamic” means the ability to re-spond instantly to changes as they occur.) Limited to networks that support hardware broadcasts.

ALOHA A multi-access contention protocol used by LinkWay. The device transmits when it wants. When it receives a reply, it continues to transmit. If it does not receive a reply, the device starts again.

Alternate mark inver-sion (AMI)

Line-coding format in T-1 transmission systems whereby successive marks are alternately inverted.

Alternate MRT (AMRT) Alternate master reference terminal—The AMRT is a backup terminal for the MRT in a LinkWay network. Normally, it acts as a traffic terminal until brought on line as the MRT. It continues to carry traffic while acting as the MRT.

Alternate SRT Alternate supporting reference terminal—The ASRT is a backup terminal for the SRT in a multiple-beam LinkWay network. Normally, it acts only as a traffic terminal until brought on line as the SRT. It continues to carry traffic while act-ing as the SRT.

AMI See “Alternate mark inversion (AMI).”

AMRT See “Alternate MRT (AMRT).”

ANM See “Answer message (ANM).”

Answer message (ANM)

A message sent in the backward direction indicating that the call has been an-swered:

• In semi-automatic working, this message has a supervisory function. • In automatic working, this message is used in conjunction with charging in-

formation in order to either start metering the charge to the calling subscriber (Rec. Q.28) or start measurement of call duration for international accounting purposes (Rec. E.260)


TERM MEANING

AR See “Access rate (AR).”

ARP See “Address resolution protocol (ARP).”

ASRT See “Alternate SRT.”

Asymmetric CIR Asymmetric committed information rate (CIR) allows a different CIR to be con-figured in each direction of a virtual circuit. It is primarily used for applications such as file transfers that require more traffic transmitted in one direction than the other.

Asynchronous A term generally used to describe occurrences that are repetitions but do not have a constant repetition period. In communications, a data transmission format in which each character is defined with a “start bit” at its beginning and a “stop bit” at its end. This allows the receiving device to recognize, and to synchronize to each individual character in a transmission, even though the time interval be-tween characters may vary.

Asynchronous transfer mode (ATM)

ATM is a flexible, high-speed packet-switched protocol. ATM is a transfer mode in which the information is organized into fixed size cells. It is asynchronous in the sense that the recurrence of cells containing information from an individual user is not necessarily periodic. It integrates all communication forms, and its services can be delivered through fiber optic bandwidths, as well as advanced digital switching systems. These services include (1) multi-channel voice com-munications, (2) high-speed data on demand, (3) video services on demand, (4) integrated video, voice, and data for Internet services, and (5) high-resolution fax services.

ATM See “Asynchronous transfer mode (ATM).”

Autonomous System On the Internet, an autonomous system is the unit of routing policy—either a sin-gle network or a group of networks controlled by a common network adminis-trator on behalf of a single administrative entity (such as a university, a business enterprise, or a business division). An autonomous system is also sometimes re-ferred to as a routing domain. An autonomous system is assigned a globally unique number, sometimes called an autonomous system number (ASN).

Available bit rate (ABR) The ATM service category used for data traffic after higher priority quality of ser-vice (QoS) traffic requirements have been satisfied. The ABR category can tol-erate delays. For each data transmission, ABR negotiates a range of acceptable bandwidths and an acceptable cell loss amount (the number of cells that can be lost in any transmission). ABR connections support LAN traffic, such as e-mail and file transfers.

Azimuth (AZ) look an-gle

The direction the antenna must look in an east/west direction, in order for it to point at the desired satellite. This, combined with the proper elevation look an-gle, points the antenna to the correct satellite.

B channel Bearer channel—An ISDN data transmission channel with an 64-kbps capacity used for the “content” of an ISDN call; also known as a “B channel,” it is used for voice or data.

B8ZS Binary eight zero substitution, a line-coding algorithm.



TERM MEANING

Backward explicit con-gestion notification (BECN)

A signaling mechanism used in a Frame Relay network to notify an interface de-vice (data terminal equipment—DTE) that congestion avoidance procedures should be initiated by the sending device. A single bit in the frame header is specified for BECN.

Bandwidth allocation, fixed

Bandwidth is allocated for the entire duration of the call. The Network Control Center (NCC) determines the amount of fixed bandwidth allocated based on the aggregate traffic requiring a committed information rate (CIR).

Bandwidth allocation, permanent

Bandwidth is reserved for certain PVC connections. This reserved bandwidth can-not be allocated to other connections even if the designated PVC connections have no data to send.

Bandwidth on demand (BoD)

Bandwidth is allocated dynamically as a function of the traffic load presented to the LinkWay network. The available bandwidth resource is distributed among all terminals based on a terminal function called “bandwidth reporter” and a fair, efficient bandwidth allocation algorithm. The bandwidth reporter continu-ously monitors the incoming traffic rate on ATM, Frame Relay, and IP virtual circuits and reports traffic requirements to the Network Control Center (NCC) that then implements BoD.

Baseband The band of frequencies occupied by the signal before it modulates the carrier (or subcarrier) frequency to form the transmitted line or radio signal.

Also: Range of frequencies within a source of information.

Basic rate interface (BRI)

An ISDN “call” is an 64-kbps (per ANSI standard) end-to-end channel controlled by a standardized protocol. A BRI includes two 64-kbps bearer (“B”) channels and a single 16-kbps delta (“D”) channel. The B-channels are used for voice or data, while the D-channel is used for signaling or X.25 packet networking.

Bc See “Committed burst size (Bc).”

Be See “Excess burst size (Be).”

BECN See “Backward explicit congestion notification (BECN).”

BER See “Bit Error Ratio (BER).”

BERT Bit error ratio test.

Bit Error Ratio (BER) Bit error ratio—The ratio of (a) the number of bits received in error in a specified period to (b) the total number of bits received in the same period.

BoD See “Bandwidth on demand (BoD).”

Bps Bits per second—The rate at which bits are transmitted.

BPSK Binary phase shift keying.

BRI See “Basic rate interface (BRI).”

BSS Broadcast satellite service.

BUC Block upconverter.

Burst A discontinuous sequence of signals, noise, or interference counted in accordance with some specific measure or criterion.




TERM MEANING

C++ A high-level programming language, developed by Borland, used in developing LinkWay products.

CAC Connection admission control—The set of actions taken by the network during the call set-up phase (or during call re-negotiation phase) in order to determine whether a connection request can be accepted or should be rejected. Routing is part of CAC actions.

Call detail record (CDR)

See “Resource Utilization Record (RUR).”

Carrier and bit timing recovery preamble (CBTR)

The sequence of bits used by the LinkWay demodulator to acquire and synchro-nize to the burst.

CB See “Control burst (CB).”

CBR See “Constant bit rate (CBR).”

CBTR See “Carrier and bit timing recovery preamble (CBTR).”

CCITT International Consultative Committee for Telegraphy and Telephony—A stan-dards organization succeeded by the International Telecommunications Union – Telecommunications sector (ITU-T).

CCW Counterclockwise—Moving the antenna in a counterclockwise direction. The con-vention is when the observer is standing at the back of the reflector looking at it.

CDR Call detail record—See “Resource Utilization Record (RUR).”

CDV Cell delay variation, a component of cell transfer delay (CTD), induced by buffer-ing and cell scheduling.

CE European Common Market Certification, one of the many certifications that LinkWay equipment meets.

Cell A small, fixed length packet. ATM cells are 53 bytes long, consisting of a five-byte header and 48 bytes of data.

Cell error ratio (CER) The ratio of the number of cells received containing one or more bit errors from one location, in a given time interval, to the total number of cells received from the same location within the same given time interval.

Cell loss ratio (CLR) Cell loss ratio for a channel is defined as the (Lost Cells/Transmitted Cells) for a given interval of time. The CLR parameter is the value of CLR that the network agrees to offer as an objective over the lifetime of the connection.

Cell misinserted ratio (CMR)

The ratio of cells received at an endpoint that was not originally transmitted by the source end, in relation to the total number of cells properly transmitted.

Cellular digital packet data (CDPD)

An open standard for using existing cellular networks for wireless data transmis-sion. Packets of data are transmitted along channels of the cellular network.

CER See “Cell error ratio (CER).”

CG See “Control group (CG).”


TERM MEANING

Channel A means of unidirectional transmission of signals between two points. A user ac-cess channel across which data travels. Within a given T1 or E1 physical line, a channel can be one of the following:

• Unchannelized—An entire T1 or E1 line is considered a channel. • Channelized—Channel is any one of N time slots within a given line. • Fractional—The T1 or E1 channel is one of a grouping of consecutively or

non-consecutively assigned time slots. Channel service unit (CSU)

An ancillary device needed to adapt the V.35 interface to the T1 (or E1) interface.

CIR See “Committed information rate (CIR).”

CLR See “Cell loss ratio (CLR).”

CMR See “Cell misinserted ratio (CMR).”

CMR See “Cell misinserted ratio (CMR).”

Commissioning The process of setting up and initiating—or “turning on”—a LinkWay terminal or network.

Committed burst size (Bc)

The maximum amount of data (in bits) that a LinkWay network agrees to transfer, under normal conditions, during a time interval Tc.

Committed information rate (CIR)

The CIR for each DLCI (data link connection identifier) specifies the maximum average data rate (in bits per second) that the network undertakes to deliver un-der normal conditions. The rate is averaged over a minimum increment of time. If exceeded, the network discards any discard-eligible packets if there is con-gestion. See “Asymmetric CIR,” “Fixed-based CIR,” “Usage-based CIR,” and “Zero CIR.”

Committed rate meas-urement interval (Tc)

The time interval during which the user can send only the Bc (committed) amount of data and Be (excess) amount of data. Tc is computed (from the subscription parameters of CIR and Bc) as Tc = Bc /CIR.

Connected telecom-munications equip-ment (CTE)

This is the European phrase for what in the US is called “customer premises equipment” (CPE).

Connection access control (CAC)

During call set up in an ATM network, CAC algorithms are used to negotiate the traffic characteristics of the connection to ensure that sufficient network re-sources are available to establish the end-to-end connection.

Constant bit rate (CBR) An ATM service category used for time-sensitive traffic, such as audio and video. CBR guarantees that audio and video cells arrive on time, with a minimal varia-tion in the spacing between cells, by reserving bandwidth for a virtual circuit.

Control burst (CB) The CB is sometimes also called “QB.”A LinkWay traffic terminal (TT) periodi-cally transmits a CB to the master reference terminal (MRT) on a multiframe basis. This burst is used for correcting the traffic terminal’s timing and fre-quency.

Control group (CG) In a LinkWay network, the groups into which the community of network elements in each satellite beam is partitioned—traffic terminals (TTs), master reference terminal (MRT), supporting reference terminals (SRTs), alternate SRTs, and the Network Control Center (NCC). Multiple CGs can be defined in each beam.



TERM MEANING

COTS Commercial off the shelf.

CPE See “Customer premises equipment (CPE).”

CPU Central processing unit.

CRC Cyclic redundancy check.

CSU See “Channel service unit (CSU).”

CTD Cell transfer delay. The collapsed time between a cell exit event at the measure-ment point 1 and the corresponding cell entry event at measurement point 2 for a particular connection.

CTE See “Connected telecommunications equipment (CTE).”

Customer premises equipment (CPE)

This is the American phrase for what in Europe is called “connected telecommuni-cations equipment” (CTE).

CW (1) Continuous wave.

(2) Clockwise—Moving the antenna in a clockwise direction (azimuth—AZ). The convention is when the observer is standing at the back of the reflector and looking at it.

CW (1)Continuous wave.

(2) Clockwise—Moving the antenna in a clockwise direction (azimuth—AZ). The convention is when the observer is standing at the back of the reflector and looking at it.

D channel Delta Channel—An ISDN channel with a capacity of 16 kbps used for signaling or X.25 packet networking, primarily for communications between the telephone company switch and ISDN adapters.

DAMA See “Demand assigned multiple access (DAMA).”

Data communications equipment (DCE)

The switching equipment, as distinguished from devices that attach to the network (data terminal equipment—DTE). It also refers to the modem equipment.

Data link connection identifier (DLCI)

A unique number attached to data frames in Frame Relay to identify the virtual circuit and tell the network how to route the data. One or more DLCI numbers is assigned to each line end point. In a mesh configuration, each end point can have one or more DLCI addresses.

Data terminal equip-ment (DTE)

The ultimate source or destination of data flowing through a network.

dB See “Decibel (dB).”

dBm Decibel milliwatt (mW).

DBS Direct broadcast satellite.

DCE See “Date communications equipment (DCE).”

DDS Direct digital synthesizer.

DE See “Discard eligible (DE).”



TERM MEANING

Decibel (dB) —A logarithmic unit of measure used for comparing two power levels:

RatiodB = Number of decibels = 10 log10 (ratio)

Demand assigned mul-tiple access (DAMA)

. A time sharing resource allocation scheme. LinkWay is a DAMA-like system.

Discard eligible (DE) A user-set bit indicating that the frame may be discarded in preference to other frames if congestion occurs. This is used to maintain the committed quality of service within the network. (See “Backward explicit congestion notification BECN.)

DLCI See “Data link connection identifier (DLCI).”

DPSK Differential phase shift keying.

DQPSK Differential quadrature phase shift keying.

DS3 A user network interface (UNI) used for ATM service and supported by LinkWay.

DTE See “Data terminal equipment (DTE).”

DUT Device under test.

E.I.R.P. Equivalent isotropic radiated power.

E1 Transmission rate of 2.048 Mbps on E1 communications lines.

E3 A user network interface (UNI) used for ATM service and supported by LinkWay.

Eb/N0 Ratio of bit energy over the white-noise energy.

Ecb Energy per channel bit.

EIA530 Synchronous serial terrestrial interface used in Frame Relay services and sup-ported by LinkWay.

Eib Energy per information bit.

EL look angle The direction the antenna must look in an up/down direction, in order for it to point at the desired satellite. This, combined with the proper AZ (azimuth) look angle, point the antenna to the correct satellite.

Excess burst size (Be) The maximum amount of uncommitted data (in bits) in excess of Bc that a Frame Relay network can attempt to deliver during a time interval Tc. These data (Be) generally are delivered with a lower probability than are Bc. The network treats Be data as eligible to be discarded.

FCC United States Federal Communications Commission.

FEC Forward error correction—Used to combat errors in the data stream.

FECN See “Forward explicit congestion notification (FECN).”

FID Frame identification value.

Fixed bandwidth allo-cation

See “Bandwidth allocation, fixed.”



TERM MEANING

Fixed-based CIR The fix-based committed information rate (CIR) virtual circuit can be provisioned with finite CIR, matching Bc and zero Be. The entire bandwidth is pre-allocated before the virtual circuit is activated. This type of virtual circuit is suitable for constant bit rate traffic such as voice over Frame Relay and leased line types of applications.

Forward explicit con-gestion notification (FECN)

A bit set used by a Frame Relay network to notify an interface device (data termi-nal equipment—DTE) that congestion avoidance procedures should be initiated by the receiving device.

FR See “Frame Relay (FR).”

Frame Relay (FR) An interface supported by LinkWay, FR is a wideband (64 kbps to 1.544 Mbps, per ANSI) packet-based data interface standard that transmits bursts of data over wide area networks. This service uses a form of packet switching in which the packets are frames of variable length (7 to 1,024 bytes). Therefore, this pro-tocol can accommodate data packets of various sizes associated with almost any native data protocol. The native protocol data unit (PDU) is wrapped into a Frame Relay frame, with header and trailer information attached. This service interfaces with Frame Relay routers, access devices and switches and uses EIA-530/RS-449/V.35 synchronous serial terrestrial interfaces up to 2 Mbps. In LinkWay, it meets all ITU standards, including the quality of service perform-ance standards.

Frame Relay frame A variable length unit of data, in Frame Relay format, that is transmitted through a Frame Relay network as pure data.

Frequency shift keying (FSK)

An FM modulation technique where frequency shifts occur because of binary digi-tal level changes rather than modulation analog signal. The carrier shifts be-tween pre-determined frequencies.

FSK See “Frequency shift keying (FSK).”

FTP File transfer protocol.

GaAs FETs Galium arsenide field effect transistors—Type of components in an amplifier, such as an LNA (low-noise amplifier) or SSPA (solid state power amplifier).

GEO Geostationary Earth orbit.

GPS Global positioning system.

GSM Global system for mobile communications.

GUI Graphical user interface.

HDLC See “High-level data link control (HDLC).”

HDTV High-definition television.

High-level data link control (HDLC)

A generic link-level communications protocol developed by the International Or-ganization for Standardization (ISO), HDLC manages synchronous, code-transparent, serial information transfer over a link connection.

HTML Hyper text markup language.

Hz Hertz, unit for frequency measurement.

ICMP Internet control message protocol.



TERM MEANING

ID Identification or identifier.

ID Identification or identifier.

IDU Indoor unit—or terminal—in a LinkWay network. Each terminal contains a mo-dem, a digital signal processor, a synthesizer, and supports IP, ATM, Frame Re-lay, or ISDN. The terminal is connected to the ODU (outdoor unit) by the IFL (interfacility link).

IESS INTELSAT Earth Station Standards

IF Intermediate frequency or interface, depending on context.

IFL Interfacility link by which the LinkWay indoor (terminal) and outdoor unit (ODU) are connected at a LinkWay site.

Integrated Services Digital Network (ISDN)

This is an ITU-T standard for a general digital telephone network that uses a digi-tal signal instead of an analog signal for voice, video, and data transmission. An international standard for voice, data, and signaling, ISDN supports both private and public numbering plans and interfaces with voice, data, and video equip-ment. It uses T1 (23B+D) or E1 (30B+D) terrestrial interfaces and provides Nx64-kbps bearer circuit-mode service.

INTELSAT International Telecommunications Satellite Organization.

International Telecom-munications Union, Telecommunications Section (ITU-T)

An international standards organization that succeeded the International Consulta-tive Committee for Telegraphy and Telephony (CCITT). The ITU also includes the Radio Section (ITU-R) and the Development Section (ITU-D).

Internet Protocol (IP) A protocol supported by LinkWay that keeps track of Internet addresses for nodes, recognizes incoming messages, and routes outgoing messages.

IP See “Internet Protocol (IP).”

ISDN See “Integrated Services Digital Network (ISDN).”

ISO International Organization for Standardization.

ISP Internet service provider.

ITU-D See “International Telecommunications Union, Telecommunications Section (ITU-T).”

ITU-R See “International Telecommunications Union, Telecommunications Section (ITU-T).”

ITU-T See “International Telecommunications Union, Telecommunications Section (ITU-T).”

kbps Kilobit per second—The standard measure of data rate and transmission capacity.

LAN Local area network, a configuration supported by LinkWay.

LIF See “Logical interface (LIF).”

Link management in-terface (LMI)

A standard for the status polling function that determines the status of the network and DLCI connections. This is an inquiry from the Frame Relay user to the network every 10 seconds. If the user does not make this inquiry every 10 sec-onds, the carrier network equipment generates an alarm.



TERM MEANING

LMDS Local multi-point distribution service.

LMI See “Link management interface (LMI).”

LNA Low-noise amplifier.

LNB See “Low-noise block downconverter (LNB).”

Logical interface (LIF) The LIF connects a LinkWay terminal to customer’s equipment and to the satel-lite.

Low-noise block downconverter (LNB)

The LNB is attached to the antenna feed output and downconverts RF to L Band.

Mbps Megabit per second.

MHz Megahertz (1,000,000 Hertz).

MPSK Minimal phase shift keying.

MRT Master reference terminal in a LinkWay network, which controls network timing and resource allocation.

Msps Megasymbols per second.

MSK Minimal shift keying.

NCC See “Network Control Center (NCC).”

Network A LinkWay network consists of the Network Control Center (NCC) and a set of sites, with the NCC collocated with one LinkWay terminal (the master refer-ence terminal—MRT) at one of the sites.

Network Control Cen-ter (NCC)

The LinkWay NCC, hosted on a Sun Microsystems workstation, is the central con-trol for the LinkWay network.

Network Management System (NMS)

The web-based, platform-independent JAVA application that the LinkWay net-work uses for monitoring network status and performance, and for performing modifications to the network.

Network User Entity authorized to send or receive traffic on network.

NMS See “Network Management System (NMS).”

NMS User An individual who has been given access to the LinkWay network through the Network Management System (NMS). The level of access rights varies.

ODU Outdoor unit in a LinkWay network—In the LinkWay 2100 and LinkWay.IP, the RFT is built into terminal. In all cases, the ODU is connected to the terminal by the IFL (interfacility link).

PABX Private automatic branch exchange.

Payload type identifier (PTI)

A part of the ATM cell identifier, used with virtual path identifier (VPI) and vir-tual channel identifier (VCI) to recognize an ATM cell on a physical transmis-sion medium.

PBX Private branch exchange.

PCB Printed circuit board.

PCM Pulse code modulation.



TERM MEANING

PCN Personal communications network.

PCR See “Peak cell rate (PCR).”

PDU See “Protocol data unit (PDU).”

Peak cell rate (PCR) A throughput parameter representing the maximum rate at which cells are to be sent to the ATM connection.

Permanent bandwidth allocation

See “Bandwidth allocation, permanent.”

Permanent virtual con-nection or circuit (PVC)

The virtual connection the LinkWay NMS User sets up with static parameters when configuring a network connection. PVCs are not tied to a given physical path through the network. Bandwidth is always reserved for the virtual circuit, whether the PVC is in use or not. PVCs are always available for immediate use.

PRI See “Primary rate interface (PRI).”

Primary rate interface (PRI)

The ISDN PRI in North America and Japan consists of 24 channels, usually di-vided into 23 B channels and 1 D channel, running over the same physical inter-face as T1. In countries where E1 is the standard, the PRI has 31 user channels, divided into 30 B channels and 1 D channel. PRI is typically used for connec-tions such as between a PBX and a central office of a local or long distance telephone company.

Private UNI See “User-to-network interface (UNI).”

Protocol data unit (PDU)

Generic terminology for “packet,” i.e., a message that contains both data and con-trol information. This enables two entities to coordinate their interaction.

PSK Phase shift keying.

PTI See “Payload type identifier (PTI).”

Public UNI See “User-to-network interface (UNI).”

PVC See ‘Permanent virtual connection or circuit (PVC).”

QAM Quadrature amplitude modulation.

QB See “Control burst (CB).”

QoS See “Quality of service parameters (QoS).”

QPSK Quadrature phase shift keying.

Quality of Service pa-rameters (QoS)

Parameters specifying how many packets or cells can be lost during a transmis-sion, how long it can take for packets or cells to reach their destination, and how much the amount of time between cells can vary. These parameters are used to determine the quality of service a given virtual circuit will provide.

RB See “Reference burst (RB).”

Redundancy One or more backup systems that is available in case the main system fails.

Reference burst (RB) The LinkWay master reference terminal (MRT) transmits the RB—a point-to-multi-point burst—to provide timing and frequency information to all traffic terminals (TTs).



TERM MEANING

Resource Utilization Record (RUR)

The LinkWay Network Management System (NMS) collects traffic usage infor-mation on a permanent virtual connection (PVC)- or circuit-call basis and inte-grates the data into flat files that are saved daily. These RUR files—sometimes known as call detail record or CDRs—are compatible with industry-standard billing software packages and can be used as the basis for either pay-as-you-use or flat policy based billing.

RF Radio frequency—Refers to frequency above baseband.

RFC 1490 This multi-protocol encapsulation enables Frame Relay from different vendors to communicate efficiently.

RFID Received frame identification value.

RFT Radio frequency transmitter or terminal, one part of the LinkWay ODU (outdoor unit).

RIP-1, -2 Routing Information Protocol – versions 1 or 2

Router A system that controls message distribution between multiple optional paths in a network. Routers use routing protocols to gain information about the network, routing metrics, and algorithms to select the “best route.”

Routing Tables In data networks, routing tables at each switching node are set up to provide an association between the incoming and outgoing links for each connection.

RS-232 A data terminal equipment (DTE) to data communications equipment (DCE) inter-face standard—Defines electromechanical interface, with several related stan-dards, define signal level, conditions and polarity at each interface connection.

RS-422 A data terminal equipment (DTE) to data communications equipment (DCE) inter-face standard—Specifies the functional and mechanical characteristics of the in-terface between DTE and DCE.

RS449 Synchronous serial terrestrial interface used in data communication services and supported by LinkWay.

RS530 Synchronous serial terrestrial interface used in data communication services and supported by LinkWay.

RUR See “Resource Utilization Record (RUR).”

Rx Receive.

Satellite interface unit (SIU)

The logical interface connecting a LinkWay terminal to a satellite.

SB See “Signaling burst (SB).”

SCPC Single channel per carrier.

SCR See “Sustained cell rate (SCR).”

SDLC Synchronous data link control.

Service Categories Classes of service used to provide different levels of service for different types of traffic. For example, ATM service categories are CBR, VBR, UBR, and ABR.

Service profiles ID (SPID)

SPIDS are used to identify the services and features a switch is to provide to an ISDN device.



TERM MEANING

Si The set of sites that makeup a LinkWay network, with i equal to the total number of sites in that network.

Signaling burst (SB) A LinkWay traffic terminal uses SBs in ALOHA fashion to send information to the MRT (master reference terminal), which forwards the information to the NCC (Network Control Center).

Site A LinkWay site consists of a set of one or more terminals (and may include a re-dundancy controller switch) connected through an interfacility link (IFL) to an ODU (outdoor unit) consisting of an RFT (radio frequency transmitter) and an antenna.

Site ID A numerical value calculated by the LinkWay system based on the assigned con-trol group and site number.

Site Number A unique number assigned to each site within a Control Group.

SIU See “Satellite interface unit (SIU).”

SOCF Start of control frame.

SOF Start of frame.

SOMF Start of multiframe.

SONET Synchronous optical network.

SPID See “Service profiles ID (SPID).”

SRT Supporting reference terminal in a LinkWay network.

SSP Service switching point.

SSPA Solid state power amplifier, such as is used in the LinkWay ODU.

Sustained cell rate (SCR)

A throughput parameter.

SVC See “Switched virtual circuit (SVC).”

Switch A device that sets up a virtual circuit and forwards cells. Switches act like routers while setting up virtual circuits; that is, they determine the best path for the cells to take. Once the virtual circuit has been set up they act as bridges, simply for-warding cells.

Switched virtual circuit (SVC)

Virtual circuits that end stations establish and tear down on demand, when they need to communicate.

T1 Transmission rate of 1.544 Mbps on T1 communications lines, the rate for ISDN lines supported by LinkWay.

TB See “Traffic burst (TB).”

TBD To be determined.

Tc See “Committed rate measurement interval (Tc).”

TCP/IP See “Transmission Control Protocol/Internet Protocol.”

TDM Time division multiplexing.



TERM MEANING

TDMA Time division multiple access—A satellite access method based on a frame struc-ture in which each frame is defined as a basic periodic interval of time during which data are transmitted and received in one or more bursts. This is the basis of the LinkWay transport mechanism.

Terminal ID The number calculated by the LinkWay system to identify a terminal in a Link-Way network site.

Terminal type Terminal types in LinkWay network are: master reference terminal (MRT), alter-nate MRT (AMRT), supporting reference terminals (SRTs), alternate SRTs (ASRT), and traffic terminals (TTs).

Terrestrial interface adapter (TIA)

The logical interface connecting a LinkWay terminal to customer equipment.

TFID Transmitted frame identification value.

TIA See “Terrestrial interface adapter (TIA).”

Traffic burst (TB) The most common type, this point-to-point burst carries user traffic in a LinkWay network.

Transmission Control Protocol/Internet Pro-tocol (TCP/IP)

A data communication standard for interconnection of dissimilar networks and computing systems, and one of many interface services supported by LinkWay.

Transponder The circuit on a communications satellite that receives the uplink signal sent from the ground, shifts its frequency to the downlink frequency, amplifies it, and then transmits it to the ground.

TSP See “TTP (or TSP).”

TT Traffic terminal in a LinkWay network.

TTP (or TSP) The protocol used by the terminals in the LinkWay network to communicate with the NCC (Network Control Center) over special management bursts (RB, SB, CB [or QB], and AB). The protocol is a connection-oriented protocol with se-lective retransmission and is tuned to operate efficiently over satellite links.

Tx Transmit.

UBR See “Unspecified bit rate.”

UL Underwriters Laboratory, one of the many certifications that LinkWay equipment meets.

UNI See “User-to-network interface (UNI).”

UNIX Operating system of the Sun Microsystems workstation that is the basis of the LinkWay Network Control Center.

Unspecified Bit Rate (UBR)

The ATM service category used for data traffic, such as TCP/IP, that can tolerate delays. UBR does not reserve any bandwidth for a connection.

Usage-based CIR A usage-based committed information rate (CIR) virtual circuit (VC) can be provi-sioned by reserving part of the bandwidth as CIR and allocating the remainder on an on-demand basis, using non-zero Bc. This type of VC is suitable for real-time variable rate applications, such as video conferencing and video streaming.



TERM MEANING

User-to-network inter-face (UNI)

A term used to describe the interface between an end station and a switch on a switched network:

• Public UNI—Connects ATM equipment within a private network (either hosts or switches) with public networks.

• Private UNI—Used exclusively to connect hosts to switches where both are managed by the same administrative entity.

V.35 International standard for trunk interface between a network access device and a packet network that defines signaling for rates larger than 19.2 kbps. Refers to data transmission up to 1,544 Mbps.

Variable bit rate (VBR) An ATM service category used for time-sensitive traffic with variable bandwidth requirements. Like CBR (constant bit rate), VBR reserves a certain amount of bandwidth for the connection but the actual bandwidth use can vary. Unlike CBR, VBR can tolerate delays.

• Variable bit rate–non-real time (VBR-NRT). • Variable bit rate–real time (VBR-RT).

VBR See “Variable bit rate (VBR).”

VC See “Virtual circuit (VC).”

VCC See “Virtual channel connection (VCC).”

VCI See “Virtual channel identifier (VCI).”

VCO Voltage controlled oscillator.

Vdc Volts, direct current.

Virtual channel con-nection (VCC)

One of two types of connections in an ATM network for routing purposes. A vir-tual path connection (VPC) is an aggregate of VCCs. Switching on cells is first done on the VPC and then on the VCC.

Virtual channel identi-fier (VCI)

A part of the ATM cell identifier. Virtual path identifier (VPI), virtual channel identifier, and payload type identifier (PTI) are used to recognize an ATM cell on a physical transmission medium. VPI and VCI are the same for cells belong-ing to the same virtual connection on a shared transmission medium.

Virtual circuit (VC) The connection between two end stations for the duration of the connection.

Virtual path connection (VPC)

One of two types of connections in an ATM network for routing purposes. A VPC is an aggregate of virtual channel connection (VCCs). Switching on cells is first done on the VPC and then on the VCC.

Virtual path identifier (VPI)

A part of the ATM cell identifier. Virtual path identifier, virtual channel identifier (VCI), and payload type identifier (PTI) are used to recognize an ATM cell on a physical transmission medium. Virtual paths provide a convenient way of bun-dling traffic directed to the same destination or traffic requiring the same Qual-ity of Service (QoS). VPI and VCI are the same for cells belonging to the same virtual connection on a shared transmission medium.

VPC See “Virtual path connection (VPC).”

VPI See “Virtual path identifier (VPI).”



TERM MEANING

VSAT Very small aperture terminal, such as in a LinkWay network—Satellite access terminals with antenna diameters of 3.8 meter or smaller.

WAN Wide area network—LinkWay supports WAN interconnection.

WLL Wireless local loop, a network setup supported by LinkWay.

Zero CIR The zero committed information rate (CIR) virtual circuit is primarily intended for non-real-time applications, such as browsing the World Wide Web. This type of service does not pre-allocate bandwidth. Instead, it allocates bandwidth in re-sponse to traffic demands. In cases of high bandwidth demand, this is the first traffic type to be dropped. This algorithm saves satellite resources for bursty non-real time traffic requirements.



APPENDIX B—LINKWAY RFT DESCRIPTIONStandard Ku-Band RFT sizes include 4-, 8-, 16-, or 40-Watts and standard C-Band RFT sizes in-clude 5-, 10-, 20-, 40-, and 60-Watts.

All configurations are essentially the same, with an SSPA or booster amplifier integrated with the BUC. The SSPA is GaAs FET biased for highly linear operation.

The RFT uses four low-noise block down-converters (LNBs) to cover the entire Ku-band receive frequency, (10.95–12.75 GHz) and one LNB for C-band receive frequencies (3.62-4.2 GHz).

The LinkWay 2100 terminal interfaces with the BUC using two coaxial cables:

The Tx IFL cable carries +24VDC or +48 VDC (all terminals shipped on or after October 1, 2001, carry the +24VDC drive voltage), the 10 MHz reference, FSK communications link, and the modulated L-Band signal from the indoor unit to the BUC. It is a double-shielded 50Ω co-axial cable with a Type N male connector at each end.

The Rx IFL cable carries the down-converted receive signal from the LNB to the indoor unit, as well as the +20VDC source voltage from the indoor unit to the LNB. It is a 75Ω coaxial cable with a Type N male connector at the indoor unit end and a Type-F male at the LNB end.

Exhibit B-1: LINKWAY RFT TRANSMIT SPECIFICATIONS

Ku-BAND

C-BAND

Output Frequency • 14.0 to 14.5 GHz • 5.845 to 6.425 GHz

1 dB Gain Compression Point

• 36, 39, 42, and 46 dBm • 37, 40, 43, 46, and 48 dBm

Output Power Adjustment Step Size (from IDU)

• 0.5 dB • 0.5 dB

Spurious (in band) • - 50 dBc • - 50 dBc

IF Interface Connector • Type N female on chassis with adapter for Type F fe-male interface

• Type N female on chassis with adapter for Type F fe-male interface

Exhibit B-2: LINKWAY RFT RECEIVE SPECIFICATIONS

Ku-BAND

C-BAND

Input Frequency • 11.7-12.2, 10.95 - 11.7, 12.25 - 12.75 GHz

• 3.625 to 4.2 GHz, 3.4 – 4.2 GHz, 4.5 – 4.8 GHz

Noise Temperature • 90 o K • 45 o K

IF Interface Connector • Type F female • Type F female



Exhibit B-3: LINKWAY OUTDOOR RFT OPERATING CHARACTERISTICS

Ku-BAND C-BAND

Operating Temperature • -40 to +55 o C • -40 to +55 o C

SSPA Power Supply

(8W Ku-band or higher, 10W C-band or higher)

• 90-240 VAC, 47-63 Hz, 1 phase

• 90-240 VAC, 47-63 Hz, 1 phase

Humidity • 0 –100% Condensing • 0 –100% Condensing

Altitude • Up to 15,000 feet • Up to 15,000 feet

Solar • 360 BTU/sq. ft/Hr @ 50 o C • 360 BTU/sq. ft/Hr @ 50 o C

Salt • As found in coastal areas • As found in coastal areas

Shock • As encountered in shipping • As encountered in shipping


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LINKWAY S2 System Description

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