Re: PCU <---> SGSN protocol trace

Just to put an answer to this, the solution is to right click on the "data" part inside the UDP packet, and select "Decode as" and choose protocol "GPRS-NS", then click OK. I also used filtering to limit the messaging to the PCU <--> SGSN part: udp.srcport==23000 or udp.dstport==23000 Hope this will help others too. Regards, Csaba ----- Eredeti üzenet ----- Feladó: "Sipos Csaba" &lt;sipos.csaba(a)kvk.uni-obuda.hu&gt; Címzett: "OpenBSC Mailing List" &lt;openbsc(a)lists.osmocom.org&gt; Elküldött üzenetek: Szombat, 2015. December 5. 15:09:20 Tárgy: PCU <---> SGSN protocol trace Dear list, I just appear to have a strange UE behavior where the UE tries to Attach (both CS and PS), the Osmo-SGSN sends an Attach accept, but the UE never responds with an Attach complete, instead after 10 seconds it tries to re-attach. I had an issue quite similar like this earlies where the UE requests for some IEs or the SGSN sends soething the UE don't like. The point is, I would like to do protocol trace between the SGSN and the PCU, and I managed to see the traffic with Wireshark, but it was not able to dissect/recognise the protocols over the UDP layer. Can someone please help me how to configure Wireshark to be able to dissect the involved protocols? Thanks! Csaba