Wide Area Network (WAN)

Agenda

• LAN/WAN Introductions• Real-World Example• Wireless WANs• WAN Potential

Bus Network with Backbone Interconnections Between Different Network Types

Token Ring Network Topology Self-healing Ring TopologyTwo rings

Star Network Topology

Network Topology

FDDIDeveloped by the American National Standards Institute (ANSI) standards committee in the mid-1980s - at a time when high-speed engineering workstations were beginning to tax the bandwidth of existing LANs based on Ethernet and Token Ring - the Fibre Distributed Data Interface (FDDI) specifies a 100 Mbit/s token-passing, dual-ring LAN using fibre-optic cable.

Token RingIn 1984, IBM introduced the 4 Mbit/s Token Ring network. Instead of the normal plug and socket arrangement of male and female gendered connectors, the IBM data connector (IDC) was a sort of hermaphrodite, designed to mate with itself. Although the IBM Cabling System is to this day regarded as a very high quality and robust data communication media, its large size and cost - coupled with the fact that with only 4 cores it was less versatile than 8-core UTP - saw Token Ring continue fall behind Ethernet in the popularity stakes. It remains IBM's primary LAN technology however and the compatible and almost identical IEEE 802.5 specification continues to shadow IBM's Token Ring development.

EthernetEthernet was developed in the mid 1970's by the Xerox Corporation, and in 1979 Digital Equipment Corporation DEC) and Intel joined forces with Xerox to standardise the system. The Institute of Electrical and Electronic Engineers (IEEE) released the official Ethernet standard in 1983 called the IEEE 802.3 after the name of the working group responsible for its development, and in 1985 version 2 (IEEE 802.3a) was released. This second version is commonly known as "Thin Ethernet" or 10Base2, in this case the maximum length is 185m even though the "2" suggest that it should be 200m.

Fast EthernetFast Ethernet was officially adopted in the summer of 1995, two years after a group of leading network companies had formed the Fast Ethernet Alliance to develop the standard. Operating at ten times the speed of regular 10Base-T Ethernet, Fast Ethernet - also known as 100BaseT - retains the same CSMA/CD protocol and Category 5 cabling support as its predecessor higher bandwidth and introduces new features such as full-duplex operation and auto-negotiation.

Client-ServerClient-server networking architectures became popular in the late 1980s and early 1990s as many applications were migrated from centralised minicomputers and mainframes to networks of personal computers. The design of applications for a distributed computing environment required that they effectively be divided into two parts: client (front end) and server (back end). The network architecture on which they were implemented mirrored this client-server model, with a user's PC (the client) typically acting as the requesting machine and a more powerful server machine - to which it was connected via either a LAN or a WAN - acting as the supplying machine.

Ethernet LANFDDI: Fiber Distributed Data Interface100 Mbps

Peer-to-peerIn a Peer-to-peer networking architecture each computer (workstation) has equivalent capabilities and responsibilities. There is no server, and computers simply connect with each other in a workgroup to share files, printers, and Internet access. It is practical for workgroups of a dozen or less computers, making it common in many SOHO environments, where each PC acts as an independent workstation that stores data on its own hard drive but which can share it with all other PCs on the network.

P2P computingBy early 2000 a revolution was underway in an entirely new form of peer-to-peer computing. Sparked by the phenomenal success of a number of highly publicised applications, "P2P computing" - as it is commonly referred to - heralded a new computing model for the Internet age and had achieved considerable traction with mainstream computer users and members of the PC industry in a very short space of time.

The Napster MP3 music file sharing application went live in September 1999, and attracted more than 20 million users by mid-2000

Gigabit EthernetThe next step in Ethernet's evolution was driven by the Gigabit Ethernet Alliance, formed in 1996. The ratification of associated Gigabit Ethernet standards was completed in the summer of 1999, specifying a physical layer that uses a mixture of proven technologies from the original Ethernet Specification and the ANSI X3T11 Fibre Channel Specification:

Use of the same variable-length (64- to 1514-byte packets) IEEE 802.3 frame format found in Ethernet and Fast Ethernet is key to the ease with which existing lower-speed Ethernet devices can be connected to Gigabit Ethernet devices, using LAN switches or routers to adapt one physical line speed to the other.

FDDI- Fibre Distributed Data Interface specifies a 100 Mbit/s token-passing, dual-ring LAN using fibre-optic cable.

Network Topology

Self Healing Net – Dual Ring

WAN Introductions

WAN Introductions

• LAN (local area network) - Network that links computers, printers and other devices located in an office, a building or even a campus

• WAN (wide area network) - System that extends for greater distances and is used to connect LANs together.

Interconnections – To link LANs into a WAN

• DSL - Speeds up to a very fast 1.54 Mbps • T1- A digital transmission link with a total signaling

speed of 1.544 Mbps • T3 - Comprised of 28 T1 lines - 45 Mbps • OC1 - 51.85 Mbps • OC3 - 155.52 Mbps • Frame Relay - A telecommunication service

designed for cost-efficient data transmission for intermittent traffic between LANs and between end-points in a WAN

Key Components of a WAN I

• Access Router - the gateway devices connected to LANs

• WAN connections - the actual connectivity between sites

Key Components of a WAN II

• DSL (Digital Subscriber Line) – 1.54 Mbps – To delivers reliable, high-speed

office-to-office connectivity over

traditional copper wires – Affordable to most small businesses

• Security - Prevent any unauthorized people from accessing communications between sites

Real-World Example

WAN (Real-World Example)

• Large architecture firm– 4 offices

• Portland, Seattle, Los Angeles, Washington DC– Reasons for implementing a WAN

• Share Internet connection• Access email• Transfer files• Foster the sense of one firm but four offices

The Past

• Frame Relay– Past to 2002– Hub-and-spoke topology

• Portland was hub• 64 Kbps, 128 Kbps, 256 Kbps to other offices

– Issues• Expensive• Inflexible• Requires routers which needed maintenance• No way to manage• Difficult to troubleshoot

The PastFrame Relay

Portland

768K

LocalTelco

768K

Frame RelayNon-Meshed

Los AngelesSeattle Washington D.C.

LocalTelco

256KLocalTelco

T1

LocalTelco

384K

Internet

256K

256K25

6K384K

T1

T1

T1

The Recent Past

• Leased Lines– 2002 to 2003– Time Division Multiplexed Leased Lines – 50% cost savings over Frame Relay

• Increased speed to 1.544Mbp for all offices

– Issues• Still hub-and-spoke• No more flexibility, just higher speeds and lower costs

The Recent PastLeased Line

Portland

T1 (Leased Line)T1 (Internet) Local

Telco

T1 (Internet)

Los Angeles

Seattle

Washington D.C.

LocalTelco

LocalTelcoT1 (leased line)

T1 (Leased Line)

T1 (Internet)LocalTelco

Internet

T1 (Internet)

T1 (Internet)

T1 (Internet)

Telco

T1 (Leased Line)T1 (Internet)

T1 (I

nter

net)

T1 (L

ease

d Li

ne)

T1 (Leased Line)T1 (Leased Line)

T1 (Leased Line)

The Present and Future• MPLS – Multi-Protocol Label Switching

– 2003 to Future– Fully meshed - 3 Mbps– Layer 2 label switching

• A label is added to the packet– Benefits

• QOS – Quality of Service• Complete control end-to-end• No IP routing so pre-defined path, no hops• Extend Ethernet• No routers• More secure• Cost savings• Converged network (voice, data, video)

The Present

9Mbps

3Mpbs

3Mbps

3Mbps

Public Internet

Public Switched TelephoneNetwork

Local / Long Distance

Videoconferencing

Portland

Seattle

Los Angeles

D.C.

Wide Area Network Provider

Partially converged MPLS Network

Local Telco

(PacBell)

Local Telco

(Verizon)

Local Telco

(Qwest)

isdn backup

isdn backup

isdn

back

up

isdn backup

The Future

10/100

10/10010/100

10/100

backup

backup

backup

backup

Public Internet

Public Switched TelephoneNetwork

Local / Long Distance

Videoconferencing

Portland

Seattle

Los Angeles

D.C.

Wide Area Network Provider

Fully converged MPLS Network (voice/video/data)

back

up

back

up

back

up

Metro Ethernet

MetroEthernet

MetroEthernet

MetroEthernet

Why not use a VPN?

• Issues– Quality, flexibility, management and ease of

use when compared to a private WAN– Internet is stable but not a priority in downtime

• Vendors cannot guarantee Service Level Agreements (SLAs)

– Requires advanced knowledge of IP Security (IPSec)

– Required special routers with VPN accelerators

WAN enhancement• Riverbed – Steelhead appliance

– Reduces the latency of the WAN• Latency is the reason why you don’t get your full bandwidth

– For example, 1.544 Mbps is actually 900 Kbps• TCP/IP has inherent limitations

– Reduces 87% of protocol overhead and unnecessary round-trips.

• Increasing bandwidth by 2.6 times– Uses special data sequencing to cache data and only send

across changes– Transaction prediction– Examples

• Users in DC connecting to Portland like LAN• Backup warm servers across the WAN and replicate the changes

– http://www.riverbed.com/

Wireless WANs

Enabling Mobile Users• Mobile Users and Wireless Technology: The Beginning

– Started with proprietary wireless technologies – Applied to Automated Data Collection years before 802.11a/b/g– 802.11b is still most common in industry– Small, hand-held wireless computing allow workers to work

throughout an entire plant or warehouse, collecting and receiving data real-time

– Referred to as Wireless Local Area Networking (WLAN)

• Wide Area Applications of Wireless Technology– IP Tunneling– Wireless Hops– Wireless Wide Area Networking (WWAN)

IP Tunneling: Roaming Across Networks

• What if users want to work wirelessly across multiple sites?– Could use DHCP and have wireless infrastructure installed at

each site– IP Tunneling can provide static IP addressing and session

persistence– Generally uses privately owned networks

IP Tunneling: Roaming Across Networks

• What is IP Tunneling?– IP Tunneling uses encapsulation to carry entire original packets

across a router using IP– The outer IP and other header information is then stripped and

the original packet is provided on the wired network– Mobile IP is a similar method, defined by TCP/IP– Most implementations require a client and/or server to manage– Our solution uses encapsulation and spanning tree to extend the

wireless network across routers– Allows roaming across subnets seamlessly

IP Tunneling Example

Wireless Hops:Extending Wired Networks

• Wireless Hops can connect and extend networks – Alternative to wired options for connecting buildings that are

100s of feet or even miles apart– Saves trouble and expense – Usually 802.11b’s range is a few hundred feet, but vendors use

high power directional antennas to extend significantly– Must have LOS (Line of Sight)

Wireless Hops Example

Wireless WANs

But…what if users need to work across a much wider geographic area such as a whole city, or even several states???

Wireless Wide Area Networks:Helping bring your favorite stuff to a store near you!

A well-known customer…

Wireless WANs• Some WWAN Fun Facts

– This technology allows route drivers to receive and transmit real-time data wherever they are (Earlier solutions involved batched data, sent by modem)

– Latest networks are shared use, packets-as-needed rather than circuit-based, making them cheaper

– Several providers…must match standard and provider– Must subscribe to provider’s service– Some interfaces use SIM cards for activation, just like mobile

phones– Basically a cellular technology – used for mobile phones as well– Limited bandwidths, speed depending on technology and

number of channels used– Similar to modem speeds: 14.4 Kbps to 114 Kbps– Some newer technologies promising 384 Kbps (EDGE)

Wireless WANs• Some Service Types

– Code-Division Multiple Access (CDMA) – Uses multiplexing, which allows numerous signals to occupy a single transmission channel

– General Packet Radio Services (GPRS) – Packet-based…used to provide data to phone and laptops

– Global System for Mobile communication (GMS) – Most widely used worldwide and is the de facto standard in Europe

– Enhanced Data GSM Environment (EDGE) – Newer faster service available since around 2001

Wireless WANs• WWAN Enables Mobile Users to:

– Download the day’s deliveries and orders– Enter new orders– Track inventory a store has on hand– Capture signatures– Print receipts– Run reports– Close out day

• Other Customers Include:– UPS– DHL– Blue Dart (Fedex)– Camera based device allowed real estate agents and appraisers

to collect property photos

Local and Wide Area Wireless

WAN Potential

Upgrade Fast WAN, More Storage

• SEC upgrades infrastructure• Increased traffic in imaging and optical

character-recognition files• System will handle 30 to 50 terabytes of

data in first year• 2 high-speed 45-Mbps pipes at every

office

Cisco, 3Com fire up new WAN routers

• Cisco faces more competition than ever • Complete refresh of enterprise WAN

access routers for 2004• Addresses security concerns/

obsolescent technology• will combine VoIP, VPN, firewall and

intrusion-detection system (IDS) support

Start-up crams more data onto WAN

• Orbit boosts throughput on WAN connections 10 times over TCP

• TCP can lead to throttled-back connections, Orbit uses a feedback mechanism to use full network connection

• Sold in pairs with one at each end of a WAN link• Pricing ranges from $12,000 for T-I throughput to

$50,000 for 200M bit/sec throughput

VoIP for Global Companies

• Potential saving of 95%, VoIP averages 2 cents per minute

• International long distance rates average 53 cents per minute

• International teleconferencing rates average 20-35 cents per minute

• Three year window of opportunity

How some rural communities are installing high-speed Internet connections

• Cable franchises are not interested in wiring rural areas for broadband

• 70 small communities are bridging the digital divide on their own

• Kutztown PA, spent $5 million to bring residents cable TV, telephone and Internet service

• Fiber-optic lines connect the entire town to the internet; costs is less than half that of private carriers

Thank You