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- Marsol Daman 3/27/17
- 1. What is the primary responsibility of the link layer? How does it differ from the network layer?
- Answer: Link Layer's responsible for transferring datagrams from one node to physically adjacent node over a link.
- 2. What is the overall purpose of parity checking or CRC?
- Answer: Main purpose is for error detection and correction bits.
- 3. What is a multiple access protocol?
- 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.
- 4. What is an advantage of channel partitioning schemes? What is a disadvantage?
- 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.
- 5. Briefly describe the operation of a CSMA (Carrier Sense Multiple Access) protocol.
- 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.
- 6. How does CSMA/CD differ from normal CSMA?
- 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.
- 7. There are two major types of turn-taking algorithm. Name and briefly describe one of them.
- Answer: Polling is when the master node invites slave nodes to transmit in turns. Some concerns would be latency or polling overhead.
- 8. What does the ARP protocol do?
- Answer: It determines the interface's MAC address.
- 9. Briefly describe the purpose of an Ethernet switch table, how the table is populated, and what happens
- if the switch needs to forward a packet to a host not in its switch table.
- 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.
- The table is populated because the switch learns which host can be reached through which interfaces.
- 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
- If an entry is found, and if the destination on the segment is on the frame, drop it, else foward it.
- 10. Broadly speaking, what is the purpose of a VLAN?
- Answer: It's a single broadcast domain. All 2 layer broadcast traffic must cross the entire LAN.
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