wiki:WikiImunesTracerouteExample

Traceroute

Open the topology Examples/Traceroute/traceroute.imn and you should see this:

Traceroute example - topology picture.

Execute the experiment, right click on the pc1 node and use Wireshark to listen to the eth0 interface.
Double click on the pc1 node to open the console shell and execute:

traceroute 10.0.8.10

to check the route to server node.

The output should be:

pc1# traceroute 10.0.8.10
traceroute to 10.0.8.10 (10.0.8.10), 64 hops max, 52 byte packets
 1  10.0.0.1 (10.0.0.1)  3.618 ms  3.929 ms  3.978 ms
 2  10.0.1.1 (10.0.1.1)  5.965 ms  5.536 ms  5.976 ms
 3  10.0.2.2 (10.0.2.2)  7.969 ms  7.530 ms  7.979 ms
 4  10.0.3.1 (10.0.3.1)  9.969 ms  9.524 ms  9.980 ms
 5  10.0.7.2 (10.0.7.2)  11.969 ms  11.524 ms  11.984 ms
 6  10.0.8.10 (10.0.8.10)  15.968 ms  15.502 ms  15.972 ms

Wireshark should show a lot of captured packages:

Traceroute example - Wireshark output.

First, pc1 sends UDP packets with TTL (time-to-live) of 1 so when the next node in the network recieves it, it lowers its
TTL for 1 and sends an ICMP error message Time-to-live exceeded back to pc1.
Because the ICMP header contains the nodes IP address, pc1 now knows the first destination. The next UDP packets
have TTL 2, so it will reach one node more than the previous. It keeps incrementing TTL and sending packets until it
reaches its final destination.

If you'd run traceroute from the server node, the output would be:

server# traceroute 10.0.0.21
traceroute to 10.0.0.21 (10.0.0.21), 64 hops max, 52 byte packets
 1  10.0.8.1 (10.0.8.1)  7.366 ms  3.788 ms  3.977 ms
 2  10.0.7.1 (10.0.7.1)  7.959 ms  5.501 ms  5.965 ms
 3  10.0.3.2 (10.0.3.2)  9.968 ms  7.462 ms  7.979 ms
 4  10.0.2.1 (10.0.2.1)  11.970 ms  9.509 ms  9.971 ms
 5  10.0.1.2 (10.0.1.2)  13.974 ms  11.475 ms  11.978 ms
 6  10.0.0.21 (10.0.0.21)  19.975 ms  15.478 ms  15.973 ms

Notice the different step values are actually the same routers but different interfaces, and the routes from pc1 and
server nodes are the same.

Last modified 4 years ago Last modified on Nov 19, 2013 9:25:21 AM

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