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WAN Technology

WAN Technology. Objectives. At the end of this presentation, you will be able to: Define a WAN and list the benefits List the types of WAN services Understand the strengths and weaknesses of each WAN service Describe the functionality of WAN interface devices. What is a WAN?.

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WAN Technology

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  1. WAN Technology

  2. Objectives At the end of this presentation, you will be able to: • Define a WAN and list the benefits • List the types of WAN services • Understand the strengths and weaknesses of each WAN service • Describe the functionality of WAN interface devices

  3. What is a WAN? • A Wide Area Network (WAN) links remote sites over long distance media, such as copper, fiber, satellite, or microwave circuit WAN

  4. Private vs. Public WANs • Private Networks • Wholly controlled by one organization • Very costly • Guarantees security and high level of service • Public Data Networks (PDNs) • Owned by common carriers • “Pay as you use” or flat-fee • ISDN, SMDS, Frame Relay, X.25, and ATM

  5. WAN Connections • Dedicated • Point-to-point connection • Leased for 24 hr X 7day/week service • T-1, E-1, E-3, Fractional T-1/E-1 • Switched • Packet-switched vs. circuit-switched • Any-to-any connection • “Pay as you use” • ISDN, SMDS, Frame Relay, X.25, and ATM

  6. WAN Connections - Illustration End Station Point-to-Point Connections Dial-up or Leased Line Hub T1/T3 Fractional T1 X.25 Frame Relay ATM SMDS ISDN “Cloud” Technologies Multiport Router

  7. IXC POP CSU/DSU TDM Channel Banks Local Address Tandem IXC POP CSU/DSU TDM Customer Premises LEC Facilities IXC Facilities T-1 Services • Most widely used telecommunications service • Reliable and cost-effective WAN service • Applications include voice, data, and/or video

  8. Transmission Rate Hierarchical Comparison • North American Digital Transmission: Committee of European Postal Telegraph (CEPT): • DS-0 = 1 VF Channel 64 Kb/s N/A = 1 VF Channel 64 Kb/s • DS-1 (T-1) = 24 VF Channels 1.544 Mb/s (E-1) = 30 VF Channels 2.048 Mb/s • DS-2 (T-2) = 96 VF Channels 6.312 Mb/s (E-2) = 120 VF Channels 8.448 Mb/s • DS-3 (T-3) = 672 VF Channels 44.736 Mb/s (E-3) = 480 VF Channels 34.368 Mb/s

  9. ApplicationRates 320K T-1/E-1 Circuit to WAN Ch 1 Ch 2 Ch 3 Ch 4 Ch 5 NTU TDM 64K Voice Data -----> Video --------------------> 128K Time Division Multiplexers (TDMs) • Performs circuit-switching • Built-in analog-to-digital converter • Supports T-1/E-1, Fractional T-1/E-1, multiple T-1s/E-1s • Integration of video, voice, and data

  10. Channel Service Unit/Data Service Unit (CSU/DSU) • Adapts physical interface on DTE to interface of DCE in a switched-carrier network. • Provides signal timing for communication between these devices. Switch DCE CSU/DSU DTE

  11. Line Interface Devices Modems and NTUs Analog Signals 56 K Analog Digital Signals Digital Signals RS232 RS232 SPEED SPEED PC Host 56 K 56 K MODEM MODEM Digital Signals 64K Kilostream Digital Signals Digital Signals RS449 RS449 Router SPEED SPEED Router 56K 56K NTU NTU Digital Signals E-1 Megastream Digital Signals Digital Signals X.21 or G.703 X.21 or G.703 Router SPEED SPEED Router 2.048M 2.048M NTU NTU

  12. Point-to-Point Protocol (PPP) • Allows a point-to-point connection between two internetworking devices • Designed primarily for use in TCP/IP internetworks • Destination of frame—communications adapter at other end of data link • Multiple protocols can be run over PPP link • Multiple vendors’ hardware linked over serial lines • True interoperability in bridging and routing WAN environments

  13. User Datagram Protocol ICMP IP - Internet Protocol Adapter Cards Internet Protocol Suite • Suite of internetworking communications protocols OSI Layers IP Layers IP Protocols Application Applications TFTP TELNET FTP SNMP Layer Presentation Session TCP - Transmission Transport Layer Control Protocol Transport Internet Layer Network ARP Data Link Network Interface Layer Physical

  14. Wide Area Networking Public Services Frame Relay Packet Switched Circuit Switched Cell Switched X.25 ISDN BRI ISDN PRI SMDS ATM 622 Mbps 2488 Mbps 45 Mbps 56/64 Kbps 1.544 Mbps 2.048 Mbps 155 Mbps

  15. Virtual Circuits • Switched (SVCs) or Permanent (PVCs) • Established among end stations • Data is routed based upon identifier information • Circuit identifiers provide the device with next hop information Virtual Circuit (PVC or SVC) Circuit Identifiers Circuit Identifiers Switch Station Station

  16. X.25 Public Service • Interface to a packet-switched WAN • ITU Standards • Connection-oriented • Supports up to E3 data rates • More popular in Europe than U.S. • Subscribers’ charges based on usage • Applications include: • Bank ATM machines • Credit card approval systems ATMterminal Backup Host VCs Host ATM terminal

  17. Frame Relay Public Service • Based on packet-switching technology • ITU Standards • Minimal error handling • Connection-oriented • Uses Permanent Virtual Circuits • Supports up to T3/E3 data rates • More popular in U.S. than Europe • Frame Relay is ideal for large corporate networks Router Router PVCs FRAD Router

  18. Integrated Services Digital Network (ISDN) Public Service • Based on circuit switching technology • ITU, ANSI standards • Carries voice, video, and data • Works over existing phone lines • Two ISDN types: BRI and PRI • Applications include: • Remote access/telecommuting • Suitable for some LAN-to-LAN connections • Long-distance video-conferencing • High-speed access to the Internet • Local access link to X.25 and FR networks

  19. ISDN Sample Network Private Network Primary E-1 Link NTU LAN NTU LAN ISDN Public Network Backup ISDN Link Router Terminal Adapter Terminal Adapter Router

  20. Switched Multi-megabit Data Service (SMDS) Public Service • A Metropolitan Area Service (MAN) • Based on cell-switching technology • Connectionless data service • Full-duplex • Supports line rates from 1.544 Mbps (T1) to 45 Mbps (T3) • Easy to add or drop connections Router SMDS Switch SMDS Switch Router

  21. Asynchronous Transfer Mode (ATM) Public Service • Based on cell-switching technology • Connection-oriented service • Full-duplex transmission • Handles all types of network traffic • Available in data rates from 1.544 Mbps (T1) to 45 Mbps (T3) • Adapts to both LAN andWAN environments Router (VNR) ATM Switch Router (VNR) ATM Switch

  22. Synchronous Optical NETwork (SONET) Optical Carrier Rates OC-1 51.840 Mbps OC-12 622.080 Mbps OC-36 1866.240 Mbps OC-3 155.520 Mbps OC-18 933.120 Mbps OC-48 2488.320 Mbps OC-9 466.560 Mbps OC-24 1244.160 Mbps

  23. Summary • Private Vs. Public WANs • Company control vs. cost • WAN Connections • Dedicated vs. switched • Key protocols • Point-to-Point Protocol and IP • WAN public services • FR, ISDN, X.25, SMDS, ATM

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