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Large Scale
Interconnects
Wide Area Network (WAN)
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Agenda
LAN/WAN Introductions
Real-World Example
Wireless WANs WAN Potential
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Bus Network with Backbone Interconnections Between Different Network Types
Token Ring Network Topology Self-healing Ring TopologyTwo rings
Star Network Topology
Network Topology
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FDDI
Developed by the American National Standards Institute (ANSI) standardscommittee in the mid-1980s - at a time when high-speed engineering workstationswere beginning to tax the bandwidth of existing LANs based on Ethernet and TokenRing - 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 IBMdata 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 qualityand robust data communication media, its large size and cost - coupled with thefact that with only 4 cores it was less versatile than 8-core UTP - saw Token Ringcontinue fall behind Ethernet in the popularity stakes. It remains IBM's primary
LAN technology however and the compatible and almost identical IEEE 802.5specification continues to shadow IBM's Token Ring development.
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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 tostandardise the system. The Institute of Electrical and Electronic Engineers(IEEE) released the official Ethernet standard in 1983 called the IEEE 802.3after the name of the working group responsible for its development, and in1985 version 2 (IEEE 802.3a) was released. This second version is commonlyknown 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 agroup of leading network companies had formed the Fast Ethernet Alliance to
develop the standard. Operating at ten times the speed of regular 10Base-TEthernet, Fast Ethernet - also known as 100BaseT - retains the sameCSMA/CD protocol and Category 5 cabling support as its predecessor higherbandwidth and introduces new features such as full-duplex operation and auto-negotiation.
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Client-ServerClient-server networking architectures became popular in the late 1980s andearly 1990s as many applications were migrated from centralisedminicomputers and mainframes to networks of personal computers. Thedesign of applications for a distributed computing environment required thatthey effectively be divided into two parts: client (front end) and server (back
end). The network architecture on which they were implemented mirrored thisclient-server model, with a user's PC (the client) typically acting as therequesting machine and a more powerful server machine - to which it wasconnected via either a LAN or a WAN - acting as the supplying machine.
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Ethernet LANFDDI: Fiber Distributed Data Interface
100 Mbps
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Peer-to-peerIn a Peer-to-peer networking architecture each computer (workstation) hasequivalent capabilities and responsibilities. There is no server, and computers
simply connect with each other in a workgroup to share files, printers, andInternet access. It is practical for workgroups of a dozen or less computers,making it common in many SOHO environments, where each PC acts as anindependent workstation that stores data on its own hard drive but which canshare 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 highlypublicised applications, "P2P computing" - as it is commonly referred to -heralded a new computing model for the Internet age and had achievedconsiderable 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 September1999, and attracted more than 20 million users by mid-2000
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Gigabit EthernetThe next step in Ethernet's evolution was driven by the Gigabit EthernetAlliance, formed in 1996. The ratification of associated Gigabit Ethernetstandards was completed in the summer of 1999, specifying a physical layerthat uses a mixture of proven technologies from the original EthernetSpecification and the ANSI X3T11 Fibre Channel Specification:
Use of the same variable-length (64- to 1514-byte packets) IEEE 802.3 frameformat found in Ethernet and Fast Ethernet is key to the ease with which existinglower-speed Ethernet devices can be connected to Gigabit Ethernet devices,using LAN switches or routers to adapt one physical line speed to the other.
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FDDI- Fibre DistributedData Interface specifiesa 100 Mbit/s token-passing, dual-ring LANusing fibre-optic cable.
Network Topology
Self Healing Net Dual Ring
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WAN Introductions
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WANIntroductions
LAN (local area network) - Network that linkscomputers, printers and other devices locatedin an office, a building or even a campus
WAN (wide area network) - System thatextends for greater distances and is used to
connect LANs together.
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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 signalingspeed 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 forintermittent traffic between LANs and between end-points in a WAN
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Key Components of a WAN I
Access Router-the gateway
devices connectedto LANs
WAN connections- the actualconnectivitybetween sites
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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 fromaccessing communications between sites
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Real-World Example
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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
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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
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The PastFrame Relay
Portland
768K
Local
Telco
768K
Frame Relay
Non-Meshed
Los AngelesSeattle Washington D.C.
LocalTelco
256K
LocalTelco
T1
LocalTelco
384K
Internet
256K
256K
256K
384K
T1
T1
T1
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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
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The Recent PastLeased Line
Portland
T1 (Leased Line)T1 (Internet) Local
Telco
T1(Inter
net)
Los Angeles
Seattle
Washington D.C.
Local
Telco
Local
TelcoT1 (leased line)
T1 (Leased Line)
T1 (Internet)Local
Telco
Internet
T1(Internet)
T1 (Internet)
T1(Internet)
Telco
T1 (Leased Line)
T1 (Internet)
T1
(Inte
rnet)
T1(Lea
sedLine)
T1 (Leased Line)T1 (Leased Line)
T1(L
easedL
ine)
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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)
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The Present
9Mbps
3Mpbs
3Mbps
3Mbps
Public Internet
Public Switched
Telephone
Network
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)
isdnbackup
isdnbackup
isdn
backu
p
isdnback
up
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The Future
10/100
10/100
10/100
10/100
backup
backup
backu
p
backup
Public Internet
Public SwitchedTelephone
Network
Local / Long Distance
Videoconferencing
Portland
Seattle
Los Angeles
D.C.
Wide Area Network
Provider
Fully converged MPLS Network (voice/
video/data)
backup
b
acku
p
backup
Metro
Ethernet
Metro
EthernetMetro
Ethernet
Metro
Ethernet
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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 LevelAgreements (SLAs)
Requires advanced knowledge of IP Security
(IPSec) Required special routers with VPN
accelerators
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WAN enhancement
Riverbed Steelhead appliance Reduces the latency of the WAN
Latency is the reason why you dont 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 sendacross 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/
http://www.riverbed.com/http://www.riverbed.com/7/27/2019 Large Scale Interconnects Wide Area Network Wan3488
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Wireless WANs
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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 receivingdata 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)
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IP Tunneling:
Roaming Across Networks
What if users want to work wirelessly across multiplesites? 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
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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
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IP Tunneling Example
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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 802.11bs range is a few hundred feet, but vendors use
high power directional antennas to extend significantly Must have LOS (Line of Sight)
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Wireless Hops Example
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Wireless WANs
Butwhat if users need to work across a much
wider geographic area such as a whole city,or even several states???
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Wireless Wide Area Networks:
Helping bring your favorite stuff to a store near you!
A well-known customer
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Wireless WANs
Some WWAN Fun Facts This technology allows route drivers to receive and transmit real-
time data wherever they are (Earlier solutions involved batcheddata, sent by modem)
Latest networks are shared use, packets-as-needed rather thancircuit-based, making them cheaper
Several providersmust match standard and provider Must subscribe to providers 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 andnumber of channels used
Similar to modem speeds: 14.4 Kbps to 114 Kbps Some newer technologies promising 384 Kbps (EDGE)
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Wireless WANs
Some Service Types Code-Division Multiple Access (CDMA) Uses multiplexing,
which allows numerous signals to occupy a single transmissionchannel
General Packet Radio Services (GPRS) Packet-basedusedto provide data to phone and laptops
Global System for Mobile communication (GMS) Most widelyused worldwide and is the de facto standard in Europe
Enhanced Data GSM Environment (EDGE) Newer fasterservice available since around 2001
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Wireless WANs
WWAN Enables Mobile Users to: Download the days 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
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Local and Wide Area
Wireless
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WAN Potential
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Upgrade Fast WAN, More Storage
SEC upgrades infrastructure
Increased traffic in imaging and opticalcharacter-recognition files
System will handle 30 to 50 terabytes ofdata in first year
2 high-speed 45-Mbps pipes at everyoffice
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Cisco, 3Com fire up new WAN routers
Cisco faces more competition than ever
Complete refresh of enterprise WANaccess routers for 2004
Addresses security concerns/obsolescent technology
will combine VoIP, VPN, firewall and
intrusion-detection system (IDS) support
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Start-up crams more data onto WAN
Orbit boosts throughput on WAN connections 10times over TCP
TCP can lead to throttled-back connections,
Orbit uses a feedback mechanism to use fullnetwork connection
Sold in pairs with one at each end of a WAN link
Pricing ranges from $12,000 for T-I throughputto $50,000 for 200M bit/sec throughput
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VoIP for Global Companies
Potential saving of 95%, VoIP averages 2cents per minute
International long distance rates average53 cents per minute
International teleconferencing ratesaverage 20-35 cents per minute
Three year window of opportunity
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How some rural communities are installing
high-speed Internet connections
Cable franchises are not interested in wiringrural 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 theinternet; costs is less than half that of privatecarriers
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Thank You