1 Consider a half-duplex point to point link using a stop
and wait scheme.
(i) What is the effect on line utilization of increasing
the message size so that fewer messages will be required?
Other factors remain constant. [2]
(ii) What is the effect on line utilization of increasing
the number of frames for a constant message size? [2]
(iii) What is the effect on line utilization of increasing
frame size? [2]
(iv) In the following figure, frames are generated
at node A and sent to node C through B. Determine the
minimum transmission rate required between B and C so
that the buffers of node B are not flooded, base don
the following: [10]
· The data rate between A and B is 100 Kbps.
· The propagation delay is 10 m sec/mile for
both sides.
· Full duplex lines between nodes.
· All data frames are 1000 bits long; track frames
are separate frames of negligible length.
· Between A and B, a sliding-window protocol
with a window size of 3 is used.
· Between B and C, stop and wait is used.
· No errors.
(v) Using Dijkstra’s algorithm, generate a least-cost
route to all other nodes for nodes A to K. Do the same
for Bellman-Ford algorithm.
(vi) Could HDLC be used as a data link control proto
col for a LAN? If not, what is missing? [5]
2 Discuss in detail about the physical description,
applications and transmission characteristics of the
following:
(i) Coaxial Cable [4]
( ii) Microwave [4]
(iii) Satellite [4]
(iv) Broadcast Radio [3]
3 (a) How does digital transmission work? How does
DM (deta modulation) improve the performance of PCM
(Pulse Code modulation)? [7]
(b) Discuss the characteristics of T1 carrier. [4]
(c) Why should PCM be preferable to DM for encoding
analog signals that represent digital data. [4]
4 Discuss the following in context of FDDI MAC protocol:
(a) List two key differences between FDDI and IEEE 802.5
[3]
(b) Illustrate graphically the operation of FDDI token
ring. [4]
(c) FDDI frame formats description [6]
(d) Priority scheme [2]
5 Answer the following questions related to IP (Internet
Protocol):
· Describe a way to do reassembly of IP fragments
at the destination. [6]
· The protocol field used in the IPV4 header
is not present in the fixed IPV6 header. Why not? [3]
· Describe IP address formats. [6]
6 Compare the following through examples.
· Transparent bridge and source routing bridge.
[6]
· Two-way handshake and three-way handshake.
[3]
· Credit allocation flow control and sliding
window flow control mechanism. [3]
· Upward multiplexing and downward multiplexing.
[3]
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