[Serusers] Processing REFER Messages

[Zeus Ng]

Proxy does not response directly to REFER request. It should relay the
request to the callee UA. The callee UA than decide whether to accept the
Refer-To header and initiate another INVITE with RURI set to the Refer-To
header.

I haven't look into detail your SIP message but I would say it should be
handled by the loose route routine. If not, check if the headers are
generated correctly on your Grandstream phone.

> -----Original Message-----
> From: serusers-bounces at lists.iptel.org 
> [mailto:serusers-bounces at lists.iptel.org] On Behalf Of Java Rockx
> Sent: Thursday, 2 June 2005 5:00 AM
> To: marian.dumitru at voice-sistem.ro
> Cc: serusers
> Subject: Re: [Serusers] Processing REFER Messages
> 
> 
> Great. Thanks for the info.
> 
> One more question. Since a call can be forwarded to another 
> SIP phone or to a PSTN phone, I need to determine how to 
> route the REFER message.
> 
> So would I basically do something like this:
> 
> route {
> 
>     if (method=='REFER') {
> 
>          if (!regeristered("location")) {
>                  rewritehostport("xxx.xxx.xxx.xxx"); # IP of 
> the PSTN gateway
>          }
> 
>          t_relay();
>     }
> }
> 
> 
> Regards,
> Paul
> 
> 
> On 6/1/05, Marian Dumitru <marian.dumitru at voice-sistem.ro> wrote:
> 
> 	Hi Paul,
> 	
> 	Just two comments:
> 	
> 	1) the message shouldn't be RURI driven, but ROUTE driven, so it
> 	shouldn't hit location.
> 	
> 	2) Refer-to URI shouldn't be used for routing the REFER 
> - this header
> 	will tell to the destination user which user to contact/refer. 
> 	
> 	Regards,
> 	Marian
> 	
> 	Java Rockx wrote:
> 	> Hi All.
> 	>
> 	> I've got a question about handling REFER messages. 
> Below is a REFER
> 	> message that my Grandstream GXP2000 phone generated 
> when I transferred a 
> 	> call to another SIP phone on the same SER proxy.
> 	>
> 	> The problem is that SER did a lookup('location') and 
> couldn't find the
> 	> phone number in the subscriber table, so it routed 
> the message to the 
> 	> PSTN gateway.
> 	>
> 	> SER should have looked at the Refer-To header to get 
> the actual
> 	> destination of the message.
> 	>
> 	> How can I get SER to handle this message correctly? 
> Should REFER
> 	> messages hit the lookup('location') function in my 
> ser.cfg script?
> 	>
> 	> NOTE: my SER proxy sits behind a Cisco 3600 so the 
> ALG functionality has
> 	> altered the IP. The message shows my SER server as IP 
> address 10.3.0.221
> 	> <http://10.3.0.221>
> 	>
> 	> Regards,
> 	> Paul
> 	>
> 	> U 2005/06/01 14:22:24.073518 66.90.46.29:5060 
> <http://66.90.46.29:5060>  <http://66.90.46.29:5060>
> 	> -> 10.3.0.221:5060 <http://10.3.0.221:5060 >
> 	> REFER sip:4075552279 at 66.243.109.99:5060 SIP/2.0.
> 	> Via: SIP/2.0/UDP 172.31.130.139
> 	> <http://172.31.130.139>;branch=z9hG4bK09ff837994d9e898. 
> 	> Route: 
> <sip:4075552279 at 10.3.0.221:5060;nat=yes;ftag=204ed7cd9666ebba;lr>.
> 	> Route: <sip:216.229.127.60:5060 
> <http://216.229.127.60:5060 >;lr>.
> 	> From: 3212514238 
> <sip:3212514238 at 66.243.109.99:5060>;tag=204ed7cd9666ebba.
> 	> To: sip:4075552279 at 66.236.245.100
> 	> <mailto: sip <mailto:sip> 
> :4075552279 at 66.236.245.100>;tag=EB25EC-B85.
> 	> Contact: <sip:3212514238 at 172.31.130.139
> 	> <mailto: sip:3212514238 at 172.31.130.139>>.
> 	> Supported: replaces.
> 	> Refer-To: <sip:3212814820 at sip.mycompany.com 
> 	> <mailto:sip:3212814820 at sip.mycompany.com>>.
> 	> Referred-By: <sip:3212514238 at 172.31.130.139 
> 	> <mailto:sip:3212514238 at 172.31.130.139>>.
> 	> Call-ID: 13195134-3326638548-685571 at 66.243.109.99 
> 	> <mailto:13195134-3326638548-685571 at 66.243.109.99>.
> 	> CSeq: 51906 REFER.
> 	> User-Agent: Grandstream GXP2000 1.0.1.8 
> <http://1.0.1.8>  <http://1.0.1.8>.
> 	> Max-Forwards: 70.
> 	> Allow:
> 	> 
> INVITE,ACK,CANCEL,BYE,NOTIFY,REFER,OPTIONS,INFO,SUBSCRIBE,UPDA
> TE,PRACK.
> 	> Content-Length: 0.
> 	
> 	-- 
> 	Voice System
> 	http://www.voice-system.ro
> 	
> 
> 
>