Ch18
- 1. 18.1 Chapter 18 Virtual-Circuit Networks: Frame Relay and ATM Copyright ? The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 2. 18.2 18-1 FRAME RELAY18-1 FRAME RELAY Frame Relay is a virtual-circuit wide-area networkFrame Relay is a virtual-circuit wide-area network that was designed in response to demands for a newthat was designed in response to demands for a new type of WAN in the late 1980s and early 1990s.type of WAN in the late 1980s and early 1990s. Architecture Frame Relay Layers Extended Address FRADs VOFR LMI Topics discussed in this section:Topics discussed in this section:
- 3. 18.3 Figure 18.1 Frame Relay network
- 4. 18.4 VCIs in Frame Relay are called DLCIs. Note
- 5. 18.5 Figure 18.2 Frame Relay layers
- 6. 18.6 Frame Relay operates only at the physical and data link layers. Note
- 7. 18.7 Figure 18.3 Frame Relay frame
- 8. 18.8 Frame Relay does not provide flow or error control; they must be provided by the upper-layer protocols. Note
- 9. 18.9 Figure 18.4 Three address formats
- 11. 18.11 18-2 ATM18-2 ATM Asynchronous Transfer Mode (ATM) is theAsynchronous Transfer Mode (ATM) is the cell relaycell relay protocol designed by the ATM Forum and adopted byprotocol designed by the ATM Forum and adopted by the ITU-T.the ITU-T. Design Goals Problems Architecture Switching ATM Layers Topics discussed in this section:Topics discussed in this section:
- 12. 18.12 Figure 18.6 Multiplexing using different frame sizes
- 13. 18.13 A cell network uses the cell as the basic unit of data exchange. A cell is defined as a small, fixed-size block of information. Note
- 14. 18.14 Figure 18.7 Multiplexing using cells
- 15. 18.15 Figure 18.8 ATM multiplexing
- 16. 18.16 Figure 18.9 Architecture of an ATM network
- 17. 18.17 Figure 18.10 TP, VPs, and VCs
- 18. 18.18 Figure 18.11 Example of VPs and VCs
- 19. 18.19 Note that a virtual connection is defined by a pair of numbers: the VPI and the VCI. Note
- 20. 18.20 Figure 18.12 Connection identifiers
- 21. 18.21 Figure 18.13 Virtual connection identifiers in UNIs and NNIs
- 22. 18.22 Figure 18.14 An ATM cell
- 23. 18.23 Figure 18.15 Routing with a switch
- 24. 18.24 Figure 18.16 ATM layers
- 25. 18.25 Figure 18.17 ATM layers in endpoint devices and switches
- 26. 18.26 Figure 18.18 ATM layer
- 27. 18.27 Figure 18.19 ATM headers
- 32. 18.32 18-3 ATM LANs18-3 ATM LANs ATM is mainly a wide-area network (WAN ATM);ATM is mainly a wide-area network (WAN ATM); however, the technology can be adapted to local-areahowever, the technology can be adapted to local-area networks (ATM LANs). The high data rate of thenetworks (ATM LANs). The high data rate of the technology has attracted the attention of designerstechnology has attracted the attention of designers who are looking for greater and greater speeds inwho are looking for greater and greater speeds in LANs.LANs. ATM LAN Architecture LAN Emulation (LANE) Client/Server Model Mixed Architecture with Client/Server Topics discussed in this section:Topics discussed in this section:
- 33. 18.33 Figure 18.24 ATM LANs
- 34. 18.34 Figure 18.25 Pure ATM LAN
- 35. 18.35 Figure 18.26 Legacy ATM LAN
- 36. 18.36 Figure 18.27 Mixed architecture ATM LAN
- 37. 18.37 Figure 18.28 Client and servers in a LANE
- 38. 18.38 Figure 18.29 Client and servers in a LANE