Network Topology Graph

There is no feature in Wireshark to create a network topology graph.

The best you can do is to have a look at

Statistics -> Endpoints
Statistics -> Conversations

See also the answers to other, similar questions.

http://ask.wireshark.org/questions/20777/how-to-determine-the-network-topology-in-a-capture
http://ask.wireshark.org/questions/249/topology-map-gui-or-otherwise

Furthermore it (usually) does not make much sense to build a topology map from a single capture file, as in the vast majority of cases you will have only traffic of one network segment in a capture file, and with that data the map would be a flat picture of the nodes in that segment and possibly some communication endpoints outside that segment. This is basically what the both Statistics methods return (see above).

To be able to build a 'network topology map' of a larger network, you would need a lot of information (capture data) from every segment.

However, instead of using capture data it is probably much easier to use (commercial) tools that probe the network and try to create a map from that data. Google will list some of those tools: https://www.google.com/?q=automatic+network+topology+mapping+tools

One interesting free tool is nmap with its topology map in the GUI.

http://nmap.org/book/zenmap-topology.html

Regards
Kurt

I run EtherApe at the same time to see the topology, then compare its log to the concurrent wireshark log to see what data was sent. It could be made simpler, but its something. Just a quick thought.