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  1. Marsol Daman 3/27/17
  2.  
  3. 1. What is the primary responsibility of the link layer? How does it differ from the network layer?
  4. Answer: Link Layer's responsible for transferring datagrams from one node to physically adjacent node over a link.
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  6. 2. What is the overall purpose of parity checking or CRC?
  7. Answer: Main purpose is for error detection and correction bits.
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  9. 3. What is a multiple access protocol?
  10. Answer: It's a single shared broadcast channel. Moreover, it's an algorithm that determines how nodes share channels and determine when a node can transmit.
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  12. 4. What is an advantage of channel partitioning schemes? What is a disadvantage?
  13. Answer: An advantage would be allocating piece to the node for exclusive use. A disadvantage would be the nodes with more to send take longer.
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  15. 5. Briefly describe the operation of a CSMA (Carrier Sense Multiple Access) protocol.
  16. Answer: CSMA listens before it transmit. If the channel sensed is idle, it transmits he entire frame. If it is busy, it defers the transmission.
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  18. 6. How does CSMA/CD differ from normal CSMA?
  19. Answer: CSMA/CD has collision detection so it aborts transmissions hat will be colliding and reduce channel wastage. CSMA doesn't do this and it has propagation delay.
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  21. 7. There are two major types of turn-taking algorithm. Name and briefly describe one of them.
  22. Answer: Polling is when the master node invites slave nodes to transmit in turns. Some concerns would be latency or polling overhead.
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  24. 8. What does the ARP protocol do?
  25. Answer: It determines the interface's MAC address.
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  27. 9. Briefly describe the purpose of an Ethernet switch table, how the table is populated, and what happens
  28. if the switch needs to forward a packet to a host not in its switch table.
  29. Answer: The purpose is fore storing and fowarding Ethernet frames, selectively foward frame to one or more links and using CSMA/CD to access a segment.
  30. The table is populated because the switch learns which host can be reached through which interfaces.
  31. When a frame is received at the switch, it records the incoming link and MAC address of the sending host. Next, it indexes the switch table using the MAC Destination address
  32. If an entry is found, and if the destination on the segment is on the frame, drop it, else foward it.
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  34. 10. Broadly speaking, what is the purpose of a VLAN?
  35. Answer: It's a single broadcast domain. All 2 layer broadcast traffic must cross the entire LAN.
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