Re: 回复: osmo-pcu always "T3193 timeout expired, freeing TBF" when osmo-sgsn send GPRS ATTACH ACCEPT

Pau Espin Pedrol pespin at
Tue May 11 16:54:34 UTC 2021


I would say the RLCMAC side looks fine. It looks like the SGSN is 
rejecting the ATTACH REQUEST. You may have a misconfiguration in the 
encryption config of osmo-sgsn?

Unfortuantely, your pcap doesn't contain the contents of the Gb 
interface ("gprs-ns" filter in wireshark), so it's difficult to say 
what's going on.

Please share a pcap containing gprs-ns (PCU<->SGSN) and gtp 
(SGSN<->GGSN) packets in order to find out what's going on. Share also a 
log file of osmo-sgsn (or use gsmtap log) with debug enabled to find out 
why is the SGSN rejecting it.

- Pau Espin Pedrol <pespin at>
* sysmocom - systems for mobile communications GmbH
* Alt-Moabit 93
* 10559 Berlin, Germany
* Sitz / Registered office: Berlin, HRB 134158 B
* Geschaeftsfuehrer / Managing Director: Harald Welte

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