eaves just 30 ports for equipment connections. 8 ATM is covered in Chapter 18. ENTERPRISE NETWORKS I: LOCAL AREA NETWORKS on that backplane. Traffic between ports on a single card does not even appear on the backplane (Refs. 9-11). REVIEW EXERCISES 1. Contrast a LAN with a WAN. 2. What are the two basic underlying transmission techniques for a LAN? 3. Name the three basic LAN topologies. Identify a fourth that is a subset of one of the three. 4. What range of BER can we expect on LANs? How are such good BERs achieved? If a LAN has 50 accesses, how many connectivities must be theoretically analyzed for sufficient S/N? 6. What two basic transmission problems must a designer face with a baseband LAN? 7. LLC derives from what familiar link-layer protocol? 8. Relate the IEEE 802 LAN standard model with the ISO seven-layer OSI model. 9. What is a LAN access protocol? 10. Name at least three responsibilities of the LLC. 11. What are the two services the LLC provides its users? 12. How are collisions detected with CSMA/CD? What is the purpose of the jam signal on CSMA/CD? 14. What is the function of a frame check sequence (FCS)? 15. Give three reasons why a MAC frame may be invalid? 16. How does a LAN know that a traffic frame is destined to it? 17. What is frame stripping? 18. How are collisions avoided using a token-passing scheme? 19. What is the function of a LAN repeater? 20. What are the four types of bridges covered in the text? 21. On what OSI layer do routers operate? REFERENCES 1. IEEE Standard Dictionary of Electrical and Electronic Terms, 6th ed., IEEE Std. 100-1996, IEEE, New York, 1996. 2. Information Technology-Pa 2, Logical Link Control, ANSI/IEEE 802.2, 1994 ed., with Amd. 3, IEEE, New York, 1994. Information Technology-Part 3: Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method, ANSI/IEEE Std. 802.3, 1996 ed., IEEE, New York, 1996. 4. Supplement to Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method-100 Mbps Operation, Type 100BaseT, IEEE Std. 802.3u