1)Consider a token-ring passing system with M stations and a single-frame operation. Assume

that interface delays are b bits per station, total propagation delay around the ring is and

transmission rate is R bps. Each station has a message to transmit during a cycle with probability

q and no message with probability 1-q. Message lengths are n bits and each bit of a message

may be received in error with probability p by a destination. A source will keep retransmitting a

frame until it has been received error free by the destination. Following a successful reception of

a frame a source station will generate a new free token.

i ) Determine the average duration of a cycle.

ii) Determine the throughput of this system.(15 points)

2) Assume that a primary station uses a broadcast channel to transmit messages to N secondary

stations and message lengths are n bits. Assume that each secondary station may receive each bit

of a message in error with probability p independent of other secondary stations. For example,

during a transmission several secondary stations may receive the message error free while other

stations may receive it in error. Primary station keeps retransmitting a message until all the

secondary stations receive the message error free (Note that it is not required that all the

secondary stations receive a message error free during a single transmission). After a station

receives a message error free, then, it ignores any subsequent retransmissions of that message.

Assume that each secondary station has its own return channel to the primary station to send an

ACK. The propagation delays, processing times and ACK frame transmission times are

negligible. (20 marks)

Determine the average number of times that the primary station has to transmit a message until it

is received by all the secondary stations.

(See next page for question no. 3)

3)Consider the PPP byte stuffing method. What are the contents of the following received

sequence of bytes after byte destuffing? (10 marks)

0x7D 0x5E 0xFE 0x24 0x7D 0x5D 0x7D 0x5D 0x62 0x7D 0x5E

4) Suppose a packet is arrive at router and is to be forwarded to another network having MTU of

576 bytes packet has an IP address of 20 bytes and data is 1534 bytes from fragmentation and

include the pertinent value of adder draw table (15 marks)

5) Telecommunication network has many types like wide area network, metropolitan area

network, local area network, campus area network, personal area network, virtual private

networks, client server network, peer to peer network, network computing. The network which is

spread over a large geographic area is known as wide area network. This network has helped

businesses which are dispersed over different regions to communicate to the head office.

Metropolitan area network covers the area of nearly one city or county. Its area and coverage is

more than the local area network and less than the wide area network. The communication of

computers in a very small geographical area is known as local area network. Campus area

network is a network which is restricted to the small geographical area which is limited to the

university campus or a building. Personal area network is a network which is limited to an

individual. Virtual private network is built on the principle of secure encrypted network in order

to provide complete security to the users. The client server network is network which is

connected to the LAN at one end and the back up server at the other end. Explain the whole

process with architecture .(20 marks)

6) The network traffic is forwarded along the desired paths during the process of routing.

However this process of routing is governed by crucial routing protocols. Explain the whole

process. (15 marks)