DOEACC Society 2006 DOEACC C Level C7 Advanced Computer Networks ( ) - Question Paper

C7-R3: ADVANCED COMPUTER NETWORKS
NOTE:
Time: three Hours Total Marks: 100
1. ans the subsequent ques..
a) discuss what trade-offs are there ranging from circuit-switched and packet-switched
networks. provide an example for every kind of network.
b) Why does 1-persistent CSMA perform badly with increasing number of contending
stations? How does p-persistent CSMA solve this problem?
c) discuss briefly how flow control is performed in TCP and why it is necessary.
d) Both UDP and TCP use port numbers to identify the destination entity when delivering a
message. provide 2 reasons for why these protocols invented a new abstract ID (port
numbers), instead of using process IDs, which already existed when these protocols
were designed.
e) Why does ATM use small fixed length cells?
f) Which would be more suitable to carry high-speed communication traffic ranging from a
category five twisted pair and a category seven twisted pair and why?
g) Differentiate ranging from PSTN (Public Switched Telephone Network) and ISDN (Integrated
Service Digital Network).
(7x4)
2.
a) elaborate the reasons for using the layered protocols?
b) 2 networks every providing reliable connection oriented service. 1 of them offers
reliable byte stream and the other offers a reliable message stream. Are these identical?
If so, what is the distinction made? If not, provide an example how they differ.
(6+12)
3.
a) How many frames per 2nd can gigabit Ethernet handle? ans should take all
relevant cases into account.
b) A switch designed for fast Ethernet has a backplane that can move 10 Gbps. How many
frames/sec can it handle in the worst case?
(9+9)
4.
a) Consider the delay of pure ALOHA versus slotted ALOHA at low load. Which 1 is
less? discuss your ans.
b) Consider building a CSMA/CD network running at one Gbps over a 1-km cable with no
repeaters. The signal speed in the cable is 200,000 km/sec. What is the minimum frame
size?
(9+9)
C7-R3 Page one of two January, 2006
1. ans ques. one and any 4 ques. from two to 7.
2. Parts of the identical ques. should be answered together and in the identical
sequence.
5.
a) An ATM network uses a token bucket scheme for traffic shaping. A new token is put into
the bucket every 5micro second. every token is good for 1 cell, which contains 48
bytes of data. What is the maximum sustainable data rate?
b) What would happen if an IP packet is received with a checksum error? Does it return an
fault or drop the packet? discuss.
(9+9)
6.
a) discuss how collision detection could fail if it was possible to send packets shorter than
the allowed minimum.
b) In IPv4, fragmentation reassembly is done at the endpoints, rather than at intermediary
routers. Does IPv4 permit routers to reassemble packets? What is an important cause
why reassembly be done at the end points?
(9+9)
7. Write notes on any 2 of the following:
a) TCP variations for performance enhancement
b) ISDN amalgamation with mobile and data services
c) Features of IPv6 in the situation of advanced communication networks.
(2x9)
C7-R3 Page two of two January, 2006

Earning:   Approval pending.