Computer Networks Project-2 (20%) – DiffServ and TCP Congestion Control

Use OPNET Simulator (PC version) to setup five TCP flows (A to A, B to B, etc.) in Use OPNET Simulator (PC version) to setup five TCP flows (A to A, B to B, etc.) in the above parking-lot configuration. Each physical link is assumed to have a bandwidtthe above parking-lot configuration. Each physical link is assumed to have a bandwidth of 100 Mbps, and each link propagation delay is assumed to be 100 us.h of 100 Mbps, and each link propagation delay is assumed to be 100 us.

Assume A, B, C, D, and E generate Poisson traffic, respectively. Each TCP flow hasAssume A, B, C, D, and E generate Poisson traffic, respectively. Each TCP flow has (1) Mean packet generation rate = 25 Mbps. (1) Mean packet generation rate = 25 Mbps. (2) IP packet length = 1500 bytes.(2) IP packet length = 1500 bytes. (3) Queuing discipline in routers: FIFO with Drop Tail. (3) Queuing discipline in routers: FIFO with Drop Tail. (4) Buffer size = adjustable between 1 to 5 packets. (4) Buffer size = adjustable between 1 to 5 packets. ECN: Once congestion occurs in a router, the ECN field in IP header is set. The ECE ECN: Once congestion occurs in a router, the ECN field in IP header is set. The ECE

(ECN Echo) bit in TCP header is set by the receiver on every ACK packet until the C(ECN Echo) bit in TCP header is set by the receiver on every ACK packet until the CWR flag is received.WR flag is received.

A

A

A

B

B

C EE

D

D

CR1 R5R4R3

R2

TCP Parameters: TCP Parameters: (1) Assume TCP-Reno is used.(1) Assume TCP-Reno is used. (2) Max. TCP Segment Size = 1480 bytes.(2) Max. TCP Segment Size = 1480 bytes. (3) Segment Processing Time = 1 msec. (3) Segment Processing Time = 1 msec. (4) Receiver’s Window Size = 20 Segments. (4) Receiver’s Window Size = 20 Segments. (5) Enable Slow Start, i.e., Initial cwnd = 1 Segment.(5) Enable Slow Start, i.e., Initial cwnd = 1 Segment. In the Simulation:In the Simulation: (1) Show the buffer occupancy (queue length) for every router vs simulation time.(1) Show the buffer occupancy (queue length) for every router vs simulation time. (2) Show the throughput (Mbps) for every TCP flow vs router buffer size.(2) Show the throughput (Mbps) for every TCP flow vs router buffer size. (3) Show the variations of cwnd for every TCP flow vs simulation time.(3) Show the variations of cwnd for every TCP flow vs simulation time. (4) Count packet loss rate in every router by assuming router’s buffer size = 2 packets.(4) Count packet loss rate in every router by assuming router’s buffer size = 2 packets. (5) Repeat (1) to (4), assume RED is enabled. Discuss on the improvements with and (5) Repeat (1) to (4), assume RED is enabled. Discuss on the improvements with and without enabling RED. Assume buffer size = 5 packets. Set up THmin = 2 without enabling RED. Assume buffer size = 5 packets. Set up THmin = 2 packet and TH max = 4 packets.packet and TH max = 4 packets. Due Day:Due Day: Demo on May 26, 27, 28, 2008. Demo on May 26, 27, 28, 2008. Report due on May 30, 2008.Report due on May 30, 2008. Deliverable Results:Deliverable Results: (1) Demo at F8010 Lab.(1) Demo at F8010 Lab. (2) A 15-page report including discussions and all the figures.(2) A 15-page report including discussions and all the figures. Where to download the OPNET Simulator (PC version):Where to download the OPNET Simulator (PC version): 140.117.164.20/pub/CN/proj2 (User ID: anonymous) 140.117.164.20/pub/CN/proj2 (User ID: anonymous)