Homework #4
  Homework #4.
Due 11:45PM, May. 4, 2016 Wednesday.
please answer the following problems for the chapter 4 of the textbook:
  1. Draw a protocol stack to show what place of MAC sublayer is.
  2. For this problem, use a formula from Chapter 4, but first state the formula, Frames arrive randomly at a 100-Mbps channel for transmission. If the channel is busy when a frame arrives, it waits its turn in a queue. Frame length is exponentially distributed with a mean of 10,000 bits/frame. For each of the following frame arrival rates, give the delay experienced by the average frame, including both queueing time and transmission time.
    (a) 90 frames/sec
    (b) 900 frames/sec
    (c) 9000 frames/sec
  3. compare and contrast Static Channel Allocation and Dynamic Channel Allocation
  4. explain terms: Carrier Sense, Collision Detection, 1-persistent CSMA
  5. In CSMA/CD algorithm, how to determine the worst time for a station to detect collision ?
  6. Consider building a CSMA/CD network running at 1 Gbps over a 1-km cable with no repeaters. The signal speed in the cable is 2000,000 km/sec. What is the minimum frame size?
  7. Does MAC sublayer provide reliable service? why?
  8. Explain the differences between 10Base-T and 10Base2 cabling
  9. Ethernet supports a protocol known as Carrier Sense Multiple Access with Collision Detection (CSMA/CD). Explain how CSMA/CD works, giving an example of how it ensures a low probability of collision when two nodes attempt to transmit at the same time.
  10. Please read RFC 894, explain how to encapsulate an IP packet into a Ethernet II frame, draw necessary diagrams to show the frame format.
  11. An IP packet to be transmitted by Ethernet is 60 bytes long, including all its headers. If LLC is not in use, is padding needed in the Ethernet frame, and if so, how many bytes?
  12. Ethernet frames must be at least 64 bytes long to ensure that the transmitter is still going in the event of a collision at the far end of the cable. Fast Ethernet has the same 64-byte minimum frame size but can get the bits out ten times faster. How is it possible to maintain the same minimum frame size?
  13. Some books quote the maximum size of an Ethernet  frame as 1518 bytes instead of 1500 bytes. Are they wrong? Explain your answer.
  14. explain the operation of a switch, and describe how it performs learning.
  15. consider the extended LAN connected using bridges B1 and B2 in the figure.

    Suppose the hash tables in the two bridges are empty. List all ports on which a packet will be forwarded for the following sequence of data transmissions:
    (a) A sends a packet to C.
    (b) E sends a packet to F.
    (c) F sends a packet to E.
    (d) G sends a packet to E.
    (e) D sends a packet to A.
    (f) B sends a packet to F.
  16. Store-and-forward switches have an advantage over cut-through switches with respect to damaged frames. Explain what it is.
  17. Provide a description of the key differences between a 10Base-T hub, an Ethernet Bridge, and an IP Router. Your answer should include appropriate diagrams and may include a table comparing the features provided by each equipment.
  18. Ethernet supports Broadcast, Unicast and Multicast transmission modes, explain in detail what is meant by each term.
  19. Explain the term of collision domain. How many collision domains are created when you segment a network with a 12-port switch?
  20. What is the purpose of Spanning Tree Protocol in a switched LAN?
  21. What is the purpose of VLAN technology? explain frame tagging of 802.1q.
  Notes for Submission  
  You must follow the Electronic Submission Guidelines to submit HW4.
You can create your submission by doing the following for e-submission:
  • 1. Create a file containing your answers
  • 2. mail this file to class mailbox, name the mail subject according to the Guidelines