I came across an interesting issue for a Swiss customer where they were having problem with Call-forward to an internal extension on their CME systems.
Call-forward to an internal extension seems quite straight-forward so I checked how telephony-service is configured and found both call-forward patterns as well as transfer-pattern were configured as .T .. so no real issue there. Customer added that it use to work fine before but not working anymore. After asking few questions I found that they recently migrated from ISDN to a SIP provider so all incoming calls are coming on SIP while I was thinking it’s all ISDN.
Ran our usual ccsip all, dial-peer all, ccapi inout debugs and found that when call is getting forwarded from 608 to 612, we are getting “SIP/2.0 302 Moved Temporarily” and then the call was getting disconnected.
SIP/2.0 302 Moved Temporarily
Via: SIP/2.0/UDP 62.2.x.x:5060;branch=z9hG4bKtjjtl830982hmqr9f6u0.1
Date: Mon, 24 Feb 2014 12:06:50 GMT
CSeq: 1 INVITE
When a call comes in on an SIP trunk and gets forwarded (CFNA / CFB / CFA), then the default behavior is for the CME to send the 302 “Moved Temporarily” SIP message to the Service Provider (SP) proxy. Sometimes provider may not support this and that was the case in this problem. Same issue is for Transfer as by default CME sends a SIP REFER message to Service Provider (SP) proxy and in this case SP was not able to handle it well.
I decided to configure the following commands before going to carrier as I was trying to disable this default behavior of CME.
voice service voip
no supplementary-service sip refer
no supplementary-service sip moved-temporarily
This fixed the issue without logging any ticket with carrier as I changed the behavior of CME.
Now when call is forwarded to 612 I was getting this instead of 302 Moved Temp.
SIP/2.0 180 Ringing
Via: SIP/2.0/UDP 62.2.X.X:5060;branch=z9hG4bKsn1fs200c8g1qq3af7f1.1
From: 072XXXXXX <sip:072XXXXXX@CableXXX:5060;user=phone>;tag=1247061884
To: 608 <sip:608@vbcOTF005.cablecom.net:5060;user=phone>;tag=12BA304-1D1B
Date: Mon, 24 Feb 2014 14:10:38 GMT
CSeq: 1 INVITE
Allow: INVITE, OPTIONS, BYE, CANCEL, ACK, PRACK, UPDATE, REFER, SUBSCRIBE, NOTIFY, INFO, REGISTER
Remote-Party-ID: “Michele 612” <sip:email@example.com.X.X>;party=called;screen=no;privacy=off