CODEWITHSUNDEEP
socketsudpwireshark
Endrew Kim
Endrew Kim

Reputation: 11

Why UDP packet is recognized as LLC protocol?

I'm posting a question because there is a blockage in writing the server program using the Boost asio library.

First of all, we're creating a capability to Ethernet each of the three laptops to relay MavLink messages.

A's address is 192.168.137.16, and it sends 17 bytes of data (MavLink packets) through UDP port 10000 to the 192.168.137.3:10000 (UDP) address within the same LAN.

The address of B is 192.168.137.3, and port 10000 (UDP) and port 12001 (UDP) are open. Replay data received from A to C.

C's address is 192.168.137.33, and data from B is relayed and processed.

The problem is when B receives data from A normally and sends it to C.

A->B normally handles packets as UDP protocols, but B->C becomes protocol-aware as ISO or LLC. I don't know the cause yet, so I'm posting questions to senior developers.

Thank you for reading the insufficient questions.

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Upvotes: 1

Views: 1624

Answers (1)

graphite
graphite

Reputation: 2960

Wireshark recognize UDP traffic on 12000-12004 ports as LLC protocol. You can change it in Edit->Preferences->Protocols->LLC. You can disable LLC dissector from there.

I can't diagnose ISO packet problem from here, but very likely it happens because dissector runs agains non-LLC packets.

You can try to generate special MavLink dissector. Check https://github.com/ArduPilot/pymavlink/blob/master/generator/mavgen_wlua.py

Upvotes: 2

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