Computer Networks
1 like418 views
This document discusses virtual circuit switching technologies Frame Relay and ATM. It describes how Frame Relay uses virtual circuits to transfer data across WANs more efficiently than X.25. Frame Relay operates at the data link and physical layers and transmits data in frames. ATM was developed to handle diverse data types including voice, video, and data. It uses fixed-size cells and defines connections with virtual paths and circuits identified by VPI/VCI numbers. ATM operates across multiple layers and provides quality of service guarantees.
Computer Networks
- 1. Chapter 18 Virtual Circuit Switching: Frame Relay and ATM McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 2. 18.1 Virtual Circuit Switching Global Addressing Virtual Circuit Identifier Three Phases Data Transfer Phase Setup Phase Teardown Phase McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 3. Figure 18.1 Virtual circuit wide area network McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 4. Figure 18.2 VCI McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 5. Figure 18.3 VCI phases McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 6. Figure 18.4 Switch and table McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 7. Figure 18.5 Source-to-destination data transfer McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 8. Figure 18.6 SVC setup request McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 9. Figure 18.7 SVC setup acknowledgment McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 10. Frame Relay(FR) Frame relay is a virtual circuit wide-area-network that was designed in response to demands for a new type of WAN. • Prior to FR, X.25 was being used. But it is being replaced by other WANs. • X.25 has several drawbacks: •It has a low 64-kbps data rate. •X.25 has extensive flow and error control at both data link and network layer. Flow and error control at both layers create a large overhead and slow down transmission. •Originally X.25 was designed for private use, not for the Internet. •Disappointed with X.25, some organization started their own private WAN by leasing T-1 0r T-3 lines from public service providers. This approach has also some limitations: •If an organization has n branches spread over an area, it needs n(n-1)/2 lines. •This type of service is not suitable for bursty data. Because T-1 or T-3 provides fixed data rate and bursty data require bandwidth-on-demand. McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 11. McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 12. Figure 18.8 Frame Relay network McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 13. Note: VCIs in Frame Relay are called DLCIs.(data link connection identifier) McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 14. Figure 18.9 Frame Relay layers McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 15. Note: Frame Relay operates only at the physical and data link layers. McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 16. Figure 18.10 Frame Relay frame McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 17. Frame Relay frame McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 18. Frame Relay frame McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 19. Note: Frame Relay does not provide flow or error control; they must be provided by the upper-layer protocols. McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 20. Figure 18.12 FRAD McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 21. 18.3 ATM(Asynchronous Transfer Mode) Design Goals Problems Architecture Switching Layers McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 22. Design Goals McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 23. Problems McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 24. Problems contd.. McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 25. Note: A cell network uses the cell as the basic unit of data exchange. A cell is defined as a small, fixed-sized block of information. McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 26. ATM multiplexing McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 27. Figure 18.16 Architecture of an ATM network McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 28. Figure 18.17 TP, VPs, and VCs McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 29. Figure 18.18 Example of VPs and VCs McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 30. Note: Note that a virtual connection is defined by a pair of numbers: the VPI and the VCI. McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 31. Figure 18.19 Connection identifiers McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 32. Figure 18.20 Virtual connection identifiers in UNIs and NNIs McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 33. Figure 18.21 An ATM cell McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 34. Figure 18.22 Routing with a switch McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 35. Figure 18.23 ATM layers McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 36. Figure 18.24 ATM layers in endpoint devices and switches McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 37. Figure 18.25 ATM layer McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 38. Figure 18.26 ATM headers McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 39. Figure 18.27 AAL1 McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 40. Figure 18.28 AAL2 McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 41. Figure 18.29 AAL3/4 McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004
- 42. Figure 18.30 AAL5 McGraw-Hill ©The McGraw-Hill Companies, Inc., 2004