Bug #3908

"PS Activation" takes long time - missing Iu-Release Command after Attach Complete

Added by efistokl over 2 years ago. Updated over 2 years ago.

Iu interface
Target version:
Start date:
Due date:
% Done:


Spec Reference:


I've noticed that it takes around 10 seconds for PS to work after a phone becomes registered on the network. Basically, the phone waited for 10 seconds after Attach Complete message and then sent Iu-ReleaseRequest and only then Service Request. (after Iu-Release completion)

If I send the Iu-ReleaseCommand (diff file sgsn-iu-release-after-attach-complete.diff, applied to 1.4.0) upon receiving Attach Complete message then the phone sends Service Request right away after Iu-Release completion.

RANAP trace without the fix - without-fix.pcap (Attach Complete - packet # 73 - there you see around 10s delay betweenand the phone sending Iu-ReleaseRequest)
RANAP trace with the fix - with-fix.pcap (Attach Complete - packet # 43)

sgsn-iu-release-after-attach-complete.diff sgsn-iu-release-after-attach-complete.diff 546 Bytes efistokl, 04/07/2019 01:29 PM
without-fix.pcap without-fix.pcap 18.2 KB efistokl, 04/07/2019 01:36 PM
with-fix.pcap with-fix.pcap 19.3 KB efistokl, 04/07/2019 01:36 PM

Related issues

Related to OsmoSGSN - Bug #1818: IuPS: CN should Iu Release in certain situationsNew10/12/2016

Associated revisions

Revision 609cdbe3
Added by efistokl over 2 years ago

gsm0408_rcv_gmm: send Iu-ReleaseCommand upon receiving Attach Complete.

UE expects to receive Iu-ReleaseCommand after Attach Complete. If it
doesn't receive it, then it sends Iu-ReleaseRequest after a timeout
which makes the "PS Activation" process long.

Change-Id: Ib5053e3cd655d08ff3fd0fefa48325fabb1797c8
Related: OS#3908


#1 Updated by laforge over 2 years ago

  • Status changed from New to Resolved
  • Assignee set to laforge
  • % Done changed from 0 to 100

See for a patch that was just merged. MAybe not the most elegant solution, but works for now.

#2 Updated by laforge over 2 years ago

  • Related to Bug #1818: IuPS: CN should Iu Release in certain situations added

#3 Updated by laforge over 2 years ago

FYI: This is incomplete because it
  1. doesn't wait for an Iu-ReleaseComplete from the RNC
  2. doesn't actually close the SCCP connection

See #1818#note-14 for some more details and spec references

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