Unit 4

Unit Contents


History of LANs
Transmission Methods and Media
LAN Protocols Introduction
Token Ring
Token Bus
Fiber Distributed Data Interface (FDDI)
Wireless LANs
LAN Protocols



This unit will introduce you to the lowest level in the protocol stack: local area networks (LANs), the most popular type of network used today. You will also learn about two important types of LANs: Ethernet, and Token Ring.


At the completion of this unit, you will be able to:

1. Identify important characteristics of baseband and broadband transmission and give the important characteristics of the baseband standards.

2. Contrast the characteristics of bus, pure ring, and star ring topologies.

3. Identify the components of the OSI 8802 (IEEE 802) protocol suite, showing their relationship to one another.

4. Explain why collisions occur in a CSMA/CD network.

5. Explain CSMA/CD message transmission logic.

6. Give the types and number of tokens that circulate on a Token Ring.

7. Explain how tokens are inserted onto and removed from a Token Ring and Token Bus.

8. Explain why Token Ring and Token Bus exhibit better performance characteristics than CSMA/CD under conditions of heavy load.

9. Give the rationale for FDDI's dual rings.

10. State the maximum throughput of the Ethernet, Token Ring, Token Bus, and FDDI LAN Standards.

11. Given a user's requirements for a LAN, identify the LAN architecture that best addresses those needs.

12. Understand the frame formats used for the LAN topics discussed.

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