This is an example of how to start looking at the relationship between ping RTT (Round Trip Time) and Data Rate. (A start only! you have more work to do! You certainly must make a plot of RTT vs Packet size). lafite-47 ott>: traceroute mouton traceroute to mouton.njit.edu (128.235.35.53), 30 hops max, 38 byte packets 1 mouton (128.235.35.53) 0.481 ms !<10> 0.482 ms !<10> 0.457 ms !<10> lafite-48 ott>: traceroute afs13 traceroute to feinberg.njit.edu (128.235.204.112), 30 hops max, 38 byte packets 1 vlan12-gw7 (128.235.32.7) 0.413 ms 0.330 ms 0.326 ms 2 feinberg (128.235.204.112) 0.396 ms 0.326 ms 0.328 ms So, lafite and mouton are on the same network. lafite and afs13 (feinberg) ``have the router vlan12-gw7 (128.235.32.7) in-between them''. (This is not quite true, will be discussed in class). ------ lafite-49 ott>: ping -s 10008 -c 3 mouton PING mouton.njit.edu (128.235.35.53) 10008(10036) bytes of data. 10016 bytes from mouton.njit.edu (128.235.35.53): icmp_seq=0 ttl=64 time=17.7 ms 10016 bytes from mouton.njit.edu (128.235.35.53): icmp_seq=1 ttl=64 time=17.7 ms 10016 bytes from mouton.njit.edu (128.235.35.53): icmp_seq=2 ttl=64 time=17.7 ms --- mouton.njit.edu ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2025ms rtt min/avg/max/mdev = 17.715/17.738/17.751/0.016 ms, pipe 2 Minimal RTT is 17.715 msec. ------ lafite-50 ott>: ping -s 10008 -c 3 afs13 PING feinberg.njit.edu (128.235.204.112) 10008(10036) bytes of data. 10016 bytes from feinberg.njit.edu (128.235.204.112): icmp_seq=0 ttl=254 time= 2.82 ms 10016 bytes from feinberg.njit.edu (128.235.204.112): icmp_seq=1 ttl=254 time= 2.79 ms 10016 bytes from feinberg.njit.edu (128.235.204.112): icmp_seq=2 ttl=254 time= 3.64 ms --- feinberg.njit.edu ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2022ms rtt min/avg/max/mdev = 2.795/3.088/3.644/0.393 ms, pipe 2 Minimal RTT is 2.795 msec. ------ lafite-51 ott>: ping -s 8 -c 3 mouton PING mouton.njit.edu (128.235.35.53) 8(36) bytes of data. 16 bytes from mouton.njit.edu (128.235.35.53): icmp_seq=0 ttl=64 time=0.772 ms 16 bytes from mouton.njit.edu (128.235.35.53): icmp_seq=1 ttl=64 time=0.396 ms 16 bytes from mouton.njit.edu (128.235.35.53): icmp_seq=2 ttl=64 time=0.352 ms --- mouton.njit.edu ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2003ms rtt min/avg/max/mdev = 0.352/0.506/0.772/0.190 ms, pipe 2 Minimal RTT is .352 msec. ------ lafite-52 ott>: ping -s 8 -c 3 afs13 PING feinberg.njit.edu (128.235.204.112) 8(36) bytes of data. 16 bytes from feinberg.njit.edu (128.235.204.112): icmp_seq=0 ttl=254 time= 0.262 ms 16 bytes from feinberg.njit.edu (128.235.204.112): icmp_seq=1 ttl=254 time= 0.69 ms 16 bytes from feinberg.njit.edu (128.235.204.112): icmp_seq=2 ttl=254 time= 0.264 ms --- feinberg.njit.edu ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2003ms rtt min/avg/max/mdev = 0.262/0.265/0.269/0.003 ms, pipe 2 Minimal RTT is .262 msec. ------ If i had added a few more datapoints, this might (hopefully would) have shown a linear relationship between packetsize and RTT. It shows lafite and feinberg almost certainly are set at at 100 Mb/s, and that mouton is set at at 10 Mb/s. Feinberg: 8*10,000/(2.795 - .262) = 80,000/2.533 bits/msec = 31,583,103 bits/sec. Multiply by 2 (back and forth): ~ 63 Mb/s. Must be set at 100Mb/s. There seems to be ``some'' delay in vlan12-gw7 (128.235.32.7) . However, this is misleading. Look at the whole picture. A ``naive'' approach would not multiply by 2 but by 4: the packet must be sent 4 times: from lafite, from router, from feinberg, from router again. This gives a speed of 126 Mb/s: impossible. This problem will be discussed in class. Mouton: 8*10,000/(17.715 - .352) = ... , 4.607Mb/s. Multiply by 2: 9.215 Mb/s Mouton must be set at 10 Mb/s. One of the problems is that lafite and mouton are connected to the rest of NJIT through Cat 3 cable, and still try to run at 100 Mb/s. Sometimes that works, often they get stuck at 10 Mb/s.