Thanks Alex.

So just to be clear, are you saying this:

1) When ser receives an INVITE it does not need to reply with "100 Trying"

2) When the SER tm module sends back the 100 Trying, the SIP UA should not be changing the Cseq header?

Regards,
Paul

On 4/15/05, Alex Vishnev <avishnev@optonline.net> wrote:

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@lists.iptel.org [mailto: serusers-bounces@lists.iptel.org] On Behalf Of Java Rockx
Sent: Friday, April 15, 2005 10:46 AM
To: serusers@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@sipdev.mycompany.net SIP/2.0.
Via: SIP/2.0/UDP 192.168.1.102:5060;branch=z9hG4bK3915905414.
From: Test User <sip:3215591439@sipdev.mycompany.net>;tag=1465261089.
To: <sip:8187768080@sipdev.mycompany.net>.
Call-ID: 2671219156@192.168.1.102.
CSeq: 101 INVITE.
Contact: <sip:3215591439@192.168.1.102:5060>.
Proxy-Authorization: Digest username="3215591439", realm="sipdev.mycompany.net", nonce="425f5e0de25efdb3f5a6125dcf2147bf30fe9177", uri="sip:8187768080@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@sipdev.mycompany.net>;tag=1465261089.
To: <sip:8187768080@sipdev.myvox.net>.
Call-ID: 2671219156@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@sipdev.mycompany.net SIP/2.0.
Via: SIP/2.0/UDP 192.168.1.102:5060;branch=z9hG4bK3499714875.
From: Test User <sip:3215591439@sipdev.mycompany.net>;tag=1465261089.
To: <sip:8187768080@sipdev.mycompany.net>;tag=cdbfe46960d7566fcbe09f199f2b328d.c2bb.
Call-ID: 2671219156@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@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@sipdev.mycompany.net>;tag=1465261089.
To: <sip:8187768080@sipdev.mycompany.net>;tag=cdbfe46960d7566fcbe09f199f2b328d.c2bb.
Call-ID: 2671219156@192.168.1.102.
CSeq: 100 ACK.
Content-Length: 0.
P-hint: Local Destination.


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