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Bug #5773

open

OsmoGGSN sends Direct Tunnel packets to the wrong IP address

Added by manatails 12 days ago. Updated 11 days ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
-
Target version:
-
Start date:
11/16/2022
Due date:
% Done:

0%

Spec Reference:

Description

When GTP-U Direct Tunnel is used, GGSN shall send all data packets to the RNC.

But sometimes when data packets are queued right after the Echo Request message from the SGSN, data packets are sent to the SGSN instead of RNC, causing SGSN to crash.

Attached is a pcap of the bug.

Packet no. 1-6 are correctly sent to the RNC at 10.27.30.100
But after packet no. 18 Echo response subsequent GTP-U packets are wrongly sent to the SGSN at 10.27.30.99 and SGSN reports Error indication.


Files

ggsn.pcap ggsn.pcap 5.22 KB manatails, 11/16/2022 01:36 PM
Actions #1

Updated by manatails 11 days ago

I found that st_pmm_idle_on_enter() from osmo-sgsn is resetting the GTP-U address.
Is it necessary when the RNC is in Direct Tunnel mode? I am not sure what the correct behavior is. Disabling st_pmm_idle_on_enter seems to fix the problem for me.

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