[Serusers] Another Looping Question

[Alex Vishnev]

Paul,
 
It looks like UA ACK 100 Trying. First of all I don't believe this is
needed. Second of all, it changes CSEQ from 101 INVITE to 100. I think
that's not valid at all. 
HTH
 
Alex
 
  _____  

From: serusers-bounces at iptel.org [mailto:serusers-bounces at lists.iptel.org] On
Behalf Of Java Rockx
Sent: Friday, April 15, 2005 10:46 AM
To: serusers at lists.iptel.org
Subject: [Serusers] Another Looping Question
 
Hi All.

Below is a snippet of an INVITE and you can see the usual "trying - your
call is important to us" in the dialog. Anyhow, for some reason SER
occasionally attempts to sent the ACK to itself, which causes a looping
condition. The last ACK shown is the start of the looping condition.

It only happens on occasion. SER should have consumed the ACK rather than
attempted to forward it.

Can anyone explain this?

Regards,
Paul

IP Legend
-------------------
10.3.0.221 - SER (behind a Cisco 3600 so ALG rewrote the IPs)
69.36.46.178 - NATed SIP UA

U 2005/04/15 02:19:16.252614 69.35.46.178:5060 -> 10.3.0.221:5060
INVITE sip:8187768080 at sipdev.mycompany.net SIP/2.0.
Via: SIP/2.0/UDP 192.168.1.102:5060;branch=z9hG4bK3915905414.
From: Test User <sip:3215591439 at sipdev.mycompany.net>;tag=1465261089.
To: <sip:8187768080 at sipdev.mycompany.net>.
Call-ID: 2671219156 at 192.168.1.102.
CSeq: 101 INVITE.
Contact: <sip:3215591439 at 192.168.1.102:5060>.
Proxy-Authorization: Digest username="3215591439",
realm="sipdev.mycompany.net",
nonce="425f5e0de25efdb3f5a6125dcf2147bf30fe9177",
uri="sip:8187768080 at sipdev.mycompany.net",
response="61996c3bdc10990fec7e245751777516", algorithm=MD5,
cnonce="ae02e47a3355bada49ce344c92f48587", qop=auth, nc=00000002.
max-forwards: 70.
Allow: INVITE, ACK, CANCEL, BYE, REFER, NOTIFY.
Content-Type: application/sdp.
Content-Length:   180.
.
v=0.
o=- 32014 3005 IN IP4 192.168.1.102.
s=-.
c=IN IP4 192.168.1.102.
t=0 0.
m=audio 13456 RTP/AVP 18 0 8 2 4 101.
a=rtpmap:101 telephone-event/8000.
a=fmtp:101 0-15.
a=ptime:20.
.

#
U 2005/04/15 02:19:16.276216 10.3.0.221:5060 -> 69.35.46.178:5060
SIP/2.0 100 trying -- your call is important to us.
Via: SIP/2.0/UDP
192.168.1.102:5060;branch=z9hG4bK3915905414;rport=5060;received=69.35.46.178
.
From: Test User <sip:3215591439 at sipdev.mycompany.net>;tag=1465261089.
To: <sip:8187768080 at sipdev.myvox.net>.
Call-ID: 2671219156 at 192.168.1.102.
CSeq: 101 INVITE.
Content-Length: 0.
.
 

#
U 2005/04/15 02:19:16.792795 69.35.46.178:5060 -> 10.3.0.221:5060
ACK sip:8187768080 at sipdev.mycompany.net SIP/2.0.
Via: SIP/2.0/UDP 192.168.1.102:5060;branch=z9hG4bK3499714875.
From: Test User <sip:3215591439 at sipdev.mycompany.net>;tag=1465261089.
To:
<sip:8187768080 at sipdev.mycompany.net>;tag=cdbfe46960d7566fcbe09f199f2b328d.c
2bb.
Call-ID: 2671219156 at 192.168.1.102.
CSeq: 100 ACK.
Content-Length: 0.
.
 

#
U 2005/04/15 02:19:16.912146 10.3.0.221:5060 -> 10.3.0.221:5060
ACK sip:8187768080 at sipdev.mycompany.net SIP/2.0.
Max-Forwards: 10.
Record-Route: <sip:10.3.0.221;ftag=1465261089;lr>.
Via: SIP/2.0/UDP 10.3.0.221;branch=0.
Via: SIP/2.0/UDP
192.168.1.102:5060;received=69.35.46.178;branch=z9hG4bK3499714875.
From: Test User <sip:3215591439 at sipdev.mycompany.net>;tag=1465261089.
To:
<sip:8187768080 at sipdev.mycompany.net>;tag=cdbfe46960d7566fcbe09f199f2b328d.c
2bb.
Call-ID: 2671219156 at 192.168.1.102.
CSeq: 100 ACK.
Content-Length: 0.
P-hint: Local Destination.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.sip-router.org/pipermail/sr-users/attachments/20050415/aae135a9/attachment.htm>