There are six questions; answer at least five of them.  You have one hour,
from 1 to 2.
Up to the first 75 words appearing after a question are taken to be the
answer to the question.  Words following the 75th word are not part of the
answer and will be ignored.
- 
Two systems S and R are connected by a 100 Mbyte/sec link.  S,
which can send 8,000 frames/sec, sends a continuous stream of 1.5 kbyte frames
to R, which can accept frames at a rate of 7,000 frames/sec.  S is
using a sliding window to for flow control.  What is the smallest window S
can use to make sure the link operates at 100% capacity?  (Keep in mind that
"not possible" could be an answer.)  Show your work.
  
- 
Assuming route cost is measured in hops and the objective is to have minimum
route costs, how would an infinite cost (hop count) be used in a routing
algorithm?  Make sure you indicate the routing algorithm used in your
explanation.
  
- 
Describe a CRC generating polynomial that provides error detection equivalent
to a single parity bit.  Justify your answer.
  
- 
True or false: any LAN in a network of bridges and LANs will be attached to at
most two active bridges.  Assume the network is fully operational (any host in
the network can send a packet to any other host in the network) and stable
(bridges and LANs are not being added to or removed from the network).  Justify
your answer.
  
- 
What would be the effect on overall throughput at the data-link level if a
WiFi-like system used collision avoidance (CA) without using carrier-sense
multiple access (CSMA)?  Justify your answer.
  
- 
Assume each router in a network uses a list of packet ids to suppress duplicate
broadcast packets.  Describe two ways a router can manage the size of packet-id
list.  Assume the network is stable (no hardware is added to or removed from
the network) and error free.
  
This page last modified on 2013 April 3.