ec2356 cn lab set1

ANNA UNIVERSITY: CHENNAI 600 025

B.E. / B.Tech. DEGREE EXAMINATIONS APRIL/MAY 2014

REGULATIONS 2008

Sixth Semester

EC2356 Computer Networks Laboratory

Time: 3 Hrs Maximum Marks: 100

1. a. Design and Implement IEEE 802.3 Protocol to operate at 10Mbps over max distance of 2500m with 4 repeaters and with minimum frame size of 512 bits and maximum

frame size of 1518 bits. (50)

b. The number 95 in Hexadecimal is to be transmitted in an 8-bit asynchronous format with odd Parity between DTE and DCE. Implement and Sketch the output. (50)

2. a. Analyze the performance of an access protocol that is operational on 10/100 Mbit/s

Ethernet, in terms of available throughput and access delay by exploring how packet

size and overload affect the link. Also show that under varying combinations of packet

lengths, network lengths and number of hosts, Ethernet is capable of good

performance for high-bandwidth applications, especially when response time is not

closely constrained. (50)

b. With a neat diagram implement the communication using Enhanced Parallel Port

(EPP) (50)

3. a. Assume that n stations attach to the Ethernet link as in Figure. A station senses the medium before sending a packet and sends the packet immediately after the medium is

idle. If a collision is detected while sending a packet, the station sends out a jam signal

and exponential back off scheme is employed. Upon a collision, the station waits for a

random time chosen from the interval [0, 2 _ max propagation delay] before

retransmitting the collided packet. Multiple collisions may happen at different places on

the Ethernet Link simultaneously, from which multiple jam signals are sent out.

Analyze the performance of the protocol by exploring how packet size and number of

nodes affect the link. (50)

b . With proper setup implement the data communication using IEEE 1284 standard (50)

www.Vidyarthiplus.com


4 . a. It is possible to make use of the broadcast mechanism in token bus systems to distribute

nearly up-to-date information about the state of individual stations to the entire system.

One such scheme involves the determination of a randomly varying set of more active

stations. These stations are given a chance to form a second logical ring above the standard

logical ring that characterizes the token bus. The transmission cycles of the system can thus

be made to alternate between standard token-passing and transmission cycles, and the

cycles of token-passing and transmission within the logical ring of more active stations. We

assume that each station makes at most one transmission when given the chance to transmit.

Analyze the performance of the protocol by assuming number of stations. (50)


5. a. Create a relevant scenario to analyze the Throughput, Average Delay and Utility of WLAN

with lower probability of packet collision for the parameters shown in table and

compare it with CSMA/CD protocols. (50)

Parameter DSSS

Slot time 20 s

SIFS 10 s

DIFS 50 s

ACCAtime 15 s

MSDU max size 2312 b

RxTxArTime 10 s

Phy preamble 192 b

b. With a neat diagram implement the communication using Extended Capabilities Port

(ECP) (50)

6. a. Create a relevant scenario to analyze the Throughput, Average Delay and Utility of WLAN

with lower probability of packet collision for the parameters shown in table and

compare it with CSMA/CD protocols. (50)

Parameter IR

Slot time 6 s

SIFS 7 s

DIFS 19 s

ACCAtime 5 s

MSDU max size 2312 b

RxTxArTime 0 s

Phy preamble 92-112 b




(ECP) (50)

7. a. Write client and server programs that communicate using your library. The server will

listen for messages and send back acknowledgements. The client will send messages and

listen for acknowledgements. The client will consider a message delivered once it receives

an acknowledgment and resend an unacknowledged message after a timeout. After a finite

number of resent messages, the client will give up and report an error. The packet size of

the data is defined by the user. If the acknowledgement message is not received in a user

defined amount of milliseconds, the message is resent in a user defined number of times

until the program moves on to the next packet of data. The server program outputs the

received data to a file. Measure the reliability of the network as a function of timeout and

throughput. Use timeouts ranging from 0ms to 200ms, and datagram sizes of 512 bytes and

8 kbytes. Show your measurements on graphs of packet loss as a function of timeout with

one line for each datagram size. (50)

b. With proper setup implement the data communication using IEEE 1284 standard (50)

8. a. If the channel capacity is b bits/sec, the frame size l bits, and the round-trip propagation

time R sec, the time required to transmit a single frame is l/b sec. After the last bit of a data

frame has been sent, there is a delay of R /2 before that bit arrives at the receiver and

another delay of at least R /2 for the acknowledgement to come back, for a total delay of R.

implement a protocol that transmits frames in such a way that the above mentioned line

utilization = l /(l + bR) can be improved. Implement the protocol and prove. (50)


9. a. If the channel capacity is b bits/sec, the frame size l bits, and the round-trip propagation

time R sec, the time required to transmit a single frame is l/b sec. After the last bit of a data

frame has been sent, there is a delay of R /2 before that bit arrives at the receiver and

another delay of at least R /2 for the acknowledgement to come back, for a total delay of R.

implement a protocol that transmits frames in such a way that the receiver can

accommodate a selected few out-of-order frames and saves bandwidth. (50)

b. With a neat diagram implement the communication using Enhanced Parallel Port

(EPP) (50)

10. a. Bellman,1 L. R. Ford Routes are advertised as vectors of (distance, direction), where distance

is defined in terms of a metric and direction is defined in terms of the next-hop router. As

that statement implies, each router learns routes from its neighboring routers perspectives

and then advertises the routes from its own perspective. Design and implement the routing



algorithm by constructing proper routing table for a network shown below. (50)


11. a. Design and implement the routing protocol for the network shown below where each

router originates information about itself, its directly connected links, and the state of those

links. This information is passed around from router to router, each router making a copy

of it and independently calculate its own best paths. (50)


(ECP) (50)

12. a. Design and implement the routing protocol for the intra-autonomous system shown

below. (50)

b. With a neat diagram implement the communication using Enhanced Parallel

Port (EPP) (50)

13. a. Internet traffic, which passes information through intermediate computers, can be

intercepted by a third party. Design and implement a system with necessary mechanisms

that allow two communicating parties to disguise information they send to each other. (50)



b. The number 65 in Hexadecimal is to be transmitted in an 8-bit asynchronous format with Even Parity between DTE and DCE. Implement and Sketch the output. (50)

14. a. Implement the Transfer of files from PC to PC using UNIX socket processing. (50)




ec2356 cn lab set1

Documents