Bug #4886

UE does not connect data when moving from 2G->3G

Added by manatails 11 months ago. Updated 11 months ago.

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I am using separate MSC and SGSN for each RAN, osmo-sgsn handles UTRAN->GERAN switching just fine, sending not attached command and causing the phone to reattach.
But when phones move from GERAN to UTRAN only some phones connect to the data network properly, while some are stuck in Activate PDP Context requests

sgsn_notworking.pcap sgsn_notworking.pcap 13.6 KB manatails, 12/02/2020 12:43 PM
sgsn_working.pcap sgsn_working.pcap 10.8 KB manatails, 12/02/2020 12:43 PM


#1 Updated by laforge 11 months ago

On Wed, Dec 02, 2020 at 12:46:39PM +0000, manatails [REDMINE] wrote:

I am using separate MSC and SGSN for each RAN,

I think that's not really as supported configuration. We don't implement any
inter-SGSN signaling. So the assumption for now is that there is only one OmsoSGSN
in a network. Anything beyond that is moving outside "known territory" for now.

#2 Updated by manatails 11 months ago

I can see that, but even if inter-SGSN signalling is not implemented, it would still be nice to handle UEs from unknown SGSNs gracefully as it already does in GERAN.

I am looking at 3GPP TS 24.008 ยง and osmo-sgsn seems to be doing its job but I am unsure why the UE doesn't want to send another service request.

#3 Updated by laforge 5 months ago

  • Related to Feature #5153: support hnbgw co-located GTP-U proxy added

#4 Updated by laforge 5 months ago

  • Related to deleted (Feature #5153: support hnbgw co-located GTP-U proxy)

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