Capture LLDP packets in SDN using Wireshark

Question

I created a simple SDN network in Mininet using this command:

sudo mn --topo single,3 --mac --switch ovsk --controller remote

َActually, this is a network with three hosts an one vSwitch. Then I added two flows:

add-flow tcp:127.0.0.1:6634 in_port=2,actions=output:1
add-flow tcp:127.0.0.1:6634 in_port=1,actions=output:2

Which 127.0.0.1 is my vSwitch. Now, h1 and h2 can ping each other correctly. My objective is making some changes in Topology Discovery of the OpenFlow and reducing LLDP packets in my network, is the objective function. I think I know how to do it, but I don't know how can I count and see LLDP packets? I have usedWire shark for it, but after applying LLDP filter, I can not see any thing. Where is the problem?

Answer 1

If you are using the latest version of wireshark you can just filter lldp and the total count writes down in displayed packets. But if you can not see this, maybe you can send your capture in zip format so that I can examine. However my guesses are:

1) Wireshark version is old.

2) Your controller and mininet network connection is problematic.Chack if it says connected to controller when running mininet.

3) Since you have a topology with just one switch, the controller that you are using does not send a lldp packet it discovers that single switch by HELLO and FEATURE_REQUEST/REPLY messsages and does not send any LLDP.

In any case a more comprehensive summary of your network and a capture is needed. I hope it works if not you can extend the problem. I am also working on same staff.