Subject: [Sip] Sent 18x with 'require:100rel' but no PRACK recieved

From: "etherchen" <[email-masked]>
Date: Fri, 19 Aug 2011 11:17:39 +0800

Hi:
  
   I'm facing a ISUP - SIP interworking issue recently.  
  
  I receive INVITE from remote SIP server and send IAM to ISUP side, ISUP reply ACM/CPG and then I send 18x with 100rel out, but I did not receive any PRACK from remote SIP server, and I re-send 18x to them. During this period, ISUP side send ANM to me. 
  
  If connect the call, but my end haven't receive PRACK yet, it become a unreliable call.
  If disconnect the call, I should not base on ANM to release a call.
  If continue 18x re-transmission untill time-out, it will have charging issue. Because ISUP side start billing base on ANM already, but my SIP side haven't start charging because not answer.
  
  Thanks.

---

From: <[email-masked]>
Date: Fri, 19 Aug 2011 15:42:42 +0530

Hi ,

First of all , please use "sip-implementers
([email-masked])" forum for the answer of this query. 

As per SIP RFC3262, you must reject the call in SIP side with 5xx (
provided you had SDP in reliable 18x ). You can reject ISUP side with a
RELEASE message.

But if you want to relax your software compliance a bit here , you can
do that,  but remember your early media negotiation may be in trouble.
If you are sure that on ISUP side the call is answered ( ANM is received
) you can proceed for sending 200 to SIP side.

Regards

Honsha 

From: [email-masked] [mailto:[email-masked]] On Behalf Of
etherchen
Sent: Friday, August 19, 2011 8:48 AM
To: sip
Subject: [Sip] Sent 18x with 'require:100rel' but no PRACK recieved

Hi:

 I receive INVITE from remote SIP server and send IAM to ISUP side, ISUP
reply ACM/CPG and then I send 18x with 100rel out, but I did not receive
any PRACK from remote SIP server, and I re-send 18x to them. During this
period, ISUP side send ANM to me. 

 If connect the call, but my end haven't receive PRACK yet, it become a
unreliable call.

 If continue 18x re-transmission untill time-out, it will have charging
issue. Because ISUP side start billing base on ANM already, but my SIP
side haven't start charging because not answer.

 Thanks.