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NET6.PPT

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NET6.PPT

  1. 1. T3: Wide-Area LAN Interconnection TUTORIAL
  2. 2.  Network design considerations  Building blocks of a LAN/WAN network  Intelligent hub  Bridge  LAN Switch  Router  Telephone Company Service Options Leased Lines Switched 56 ISDN Frame Relay ATM Sequence
  3. 3. TCP/IP SNA IPX DECnet WAN Novell LAN Server NETBIOS IBM LAN Server IBM Mainframe UNIX Workstation Digital Host SNA IBM Controller AppleTalk Apple LAN ? ? ? ? LAN/WAN Integration
  4. 4.  "Routable" vs. "Non-routable"  TCP/IP  IPX  APPN  Connectionless vs. connection-oriented transport  TCP/IP  IPX  Broadcasts/route updates  NetBIOS - Name Query  TCP/IP - ARP, RIP, OSPF  NetWare - Service Advertising Protocol (SAP), RIP  Appletalk - Zone Information Protocol (ZIP) & AARP  NetBIOS  DECNET  SNA  SNA  NetBIOS Protocol Implications
  5. 5. Broadcast Frame Netware Get Nearest Server Query Netware Server IPX Broadcast Example
  6. 6.  Network design considerations  Building blocks of a LAN/WAN network  Intelligent hub  Bridge  LAN Switch  Router  Telco WAN Options  Leased Lines  Switched 56  ISDN  Frame Relay  ATM Agenda
  7. 7. application gateways Presentation Session Transport Network Data Link Physical Application OSI reference model hubs/multiplexors bridges/switches routers tunneling/encapsulation Positioning the Technologies
  8. 8. Source Routing Bridges  At layer 1, isolates LAN segments to increase performance, availability  At layer 2, connects LANs into a single logical network Functions independently of higher layer protocols Operates as plug and play device B B B B B B B B B B B B Transparent Bridges Bridge
  9. 9. Bridge Bridge Bridge Bridge Bridge Broadcast Frame Bridge Bridge Netware Server Netware Get Nearest Server Query Broadcast Example
  10. 10. Token Ring Bandwidth 0 1,000,000 2,000,000 3,000,000 4,000,000 4,000,000 1,544,000 528,000 256,000 128,000 64,000 19,200 9,600 T1 512K 256K 128K 64K 19.2K 9.6K Relative Bandwidth of various media
  11. 11. Net A Net C Net D Net E Net 2  Isolates logical subnetworks for more efficient network utilization over WAN  End station sends traffic to router; router forwards toward ultimate destination  Routing protocols allow router to understand network topology DSU/CSU DSU/CSU DSU/CSU Router Router Router Net B Net 3 Net 1 Router
  12. 12. Router Router Router Router Router Broadcast Frame Bridge Bridge Netware Server Netware Get Nearest Server Query Broadcast Example
  13. 13. Router WAN Considerations  Port Density  Port Cost  Multiprotocol  Primary Role  Provide Managed Bandwidth for Slower WAN Lines Switch Router Router WAN 9.6K 19.2K 64K 128K 512K 1.544 MB LAN 4MB 10MB 16MB 100MB 155MB
  14. 14. WAN Challenge  Enterprise spans multiple locations  Requirement to share information or applications between the locations  Must balance performance against cost Raleigh, NC Richmond, VA
  15. 15. Components of a Wide-Area Network Raleigh, NC LEC e.g. BellSouth LEC e.g. Bell Atlantic IXC e.g. AT&T, Sprint, MCI,... LEC = "Local Exchange Carrier" IXC = "Inter-Exchange Carrier" "Local Loop" "Local Loop" Richmond, VA
  16. 16. "Leased Line" Network Raleigh, NC LEC LEC IXC LEC = "Local Exchange Carrier" IXC = "Inter-Exchange Carrier" = carrier multiplexing Richmond, VA  Carrier-provided facility – "owned" bandwidth – idle facility unused  Low latency – data simply relayed from one set of wires to the next  High cost – especially for LAN applications
  17. 17. "Switched" Network Services Raleigh, NC LEC LEC IXC  Analog dial  Integrated Services Digital Network (ISDN) Narrowband/Wideband/Broadband  Switched 56 Richmond, VA  Lowers Line Cost  Charged for usage time  Requires Call Setup & Call Take Down
  18. 18. WAN Technologies Fast Packet Switching Frame Relay Cell Relay ATM SMDS – Efficient handling of variable- sized frames – data only (today) – up to 1.5Mbps (today) – Scalability (up to Gbps) – QoS – Voice/Vide o/ Data/MM  Cost-effective shared facilities – with some built-in bandwidth management  Low latency – connection-oriented packet forwarding – no hop-by-hop error checking ATM: Asynchronous Transfer Mode SMDS: Switched Multimegabit Data Services
  19. 19. Local Carrier Frame Relay Networking Raleigh, NC LEC Frame Relay Service LEC = "Local Exchange Carrier" = switch Chapel Hill, NC
  20. 20. Inter-Exchange Frame Relay Networking Raleigh, NC LEC LEC Frame Relay Network LEC = "Local Exchange Carrier" IXC = "Inter-Exchange Carrier" = carrier multiplexing = switch Richmond, VA
  21. 21. Frame Relay Network ROUTER  Multiple virtual circuits over a Single Physical Link  Pricing is usually lower and distance-insensitive  however tariffs vary widely  Can be a cost-effective alternative to private lines  Bandwidth specified via Committed Information Rate & Burst Size Router Router Router Router
  22. 22. Cell Relay: Asynchronous Transfer Mode (ATM)  Digital service starting at 45Mbps  Fixed length "cells" of data  Voice, video, data, multimedia  Bandwidth Management  ITU-T Q.2931  Quality of Service
  23. 23. Quality of Service: A Key Concept... – Quality of Service (QoS): – A set of parameters that specify the required characteristics of a network path – Include characteristics such as throughput, acceptable delay, tolerance for cell loss,... – Specified in the ATM User to Network Interface (UNI) standards  Gives users the ability to specify what is required  Gives the "network" responsibility to: – allocate and free the required network resources – guarantee that committed network characteristics are met "QoS"
  24. 24. Removing the WAN Bottleneck Switch Router Router LAN 4MB 10MB 16MB 100MB 155MB WAN 9.6K 19.2K 64K 128K 512K 1.544 MB
  25. 25. ATM Extended Campus Switch  Extended LAN Environment  Multiprotocol  Campus Network "Business as Usual" LAN 4MB 10MB 16MB 100MB 155MB WAN 45MB 100MB 155MB Switch
  26. 26. WAN Technologies Fast Packet Switching  Exploits new technologies to achieve better performance characteristics  Some built-in bandwidth management Leased Lines  Carrier-provided facility – "owned" bandwidth – idle facility unused  Low latency – data simply relayed from one set of wires to the next  High cost – especially for LAN applications Switched (Switched 56, ISDN)  Lowers the cost of leased lines by charging for usage time  Requires effort to set up and tear down call at appropriate times
  27. 27. Evolution: Initial Network OKReset OKReset OK Reset OK Reset
  28. 28. Saving Costs With Frame Relay OKReset OKReset OK Reset OK Reset Frame Relay WAN
  29. 29. Evolution: Exploiting an ATM Backbone OK Reset OKReset OKReset Frame Relay ATM Backbone OK Reset
  30. 30. Evolution: Supporting Time-Sensitive Applications OK Reset OK Reset OK Reset Frame Relay ATM Backbone MM Server MM Client Multi-Service Access Switch Multi-Service Access Switch Video Conferencing Video Conferencing OK Reset
  31. 31. How do you choose the right technology? Data Center Infrequent use Frequent use Dedicated Access Switched Access High Bandwidth
  32. 32. Choosing the Right Services Switched Access - Occasional Use Dedicated Access - Frequent Use High-Bandwidth - Specialized Applications Leased Line - low delay, simple, reliable Frame Relay - potentially lower cost, cost effective support of bursty traffic Analog Dial - simple, low-bandwidth, inexpensive Switched 56 - equipment inexpensive, future??? ISDN - expensive equipment (depending on features), service pricing??? ATM - Voice, Video, Multimedia SMDS - future???

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