Bug #4886: UE does not connect data when moving from 2G->3G - OsmoSGSN - Open Source Mobile Communications

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Bug #4886

open

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

Added by manatails about 3 years ago. Updated almost 3 years ago.

Status:

New

Priority:

Normal

Assignee:

Category:

Target version:

Start date:

12/02/2020

Due date:

% Done:

Spec Reference:

Description

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

Files

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

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Updated by laforge about 3 years 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.

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Updated by manatails almost 3 years 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 § 4.7.13.4 and osmo-sgsn seems to be doing its job but I am unsure why the UE doesn't want to send another service request.

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