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.
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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.
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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.
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Describe a CRC generating polynomial that provides error detection equivalent
to a single parity bit. Justify your answer.
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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.
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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.
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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.