TCL script to transfer without hairpin

Version 1
    This document was generated from CDN thread

    Created by: Raymond Maslanka on 19-08-2011 01:36:13 PM
    I have a CUCM and 2911 ISR gateway.  The gateway has a T1 connected to an IVR system and the T1 controller is configured as "ds0-group 1 timeslots 1-24 type fxs-loop-start".  I can use the app-h450-transfer.2.0.0.10.tcl to handle hookflashes and transfers by the IVR system successfully, but do not want to have the calls hair-pin from the gateway.  As it is now, once the call is transfered, the T1 port goes idle but the H.323 or SIP call legs and media streams stay up on the gateway.
     
    Is there a way to implement this script so that the gateway is not participating in the call after the transfer?
     
    Is there a alternate script developed / available somewhere that can do the same?
     
    I suspect this may be possible through some implementation of SIP / REFER method, and I am hoping you can confirm whether it is possible and proven anywhere.

    Subject: RE: TCL script to transfer without hairpin
    Replied by: Raymond Maslanka on 19-08-2011 02:57:41 PM
    I believe the script is designed to use mode REDIRECT_ROTARY when the local-hairpin parameter is not set to 1.

    My current router config looks like this:

    service transfer flash:app-h450-transfer.2.0.0.10.tcl
      paramspace english language en
      paramspace english index 0
      paramspace english location flash:/PROMPTS/EN/
      paramspace english prefix en
      paramspace english delay-time 1

    While testing, I still see call-legs established after the transfer.

    Telephony call-legs: 0
    SIP call-legs: 0
    H323 call-legs: 2
    Call agent controlled call-legs: 0
    SCCP call-legs: 0
    Multicast call-legs: 0
    Total call-legs: 2

    Is there something else I may be missing?

    Subject: RE: TCL script to transfer without hairpin
    Replied by: Raymond Maslanka on 19-08-2011 03:23:34 PM
    After the transfer, I see connections between the gateway at 192.168.1.45, the caller at 10.199.2.187 and the transferee at 10.199.1.188...

    Router#sh voip rtp con
    VoIP RTP active connections :
    No. CallId     dstCallId  LocalRTP RmtRTP LocalIP                                RemoteIP
    1   451        455        18362    30636  192.168.1.45                           10.199.2.187
    2   455        451        18032    19786  192.168.1.45                           10.199.2.188
    Found 2 active RTP connections

    Subject: RE: TCL script to transfer without hairpin
    Replied by: Raymond Maslanka on 19-08-2011 03:33:49 PM
    The voip dial peer on the gateway is H.323.  The devices at 10.199.2.187 and 10.199.2.188 are 7900 series phones using SCCP.

    dial-peer voice 101 voip
    preference 1
    service transfer
    destination-pattern [1-8]...
    voice-class h323 1
    session target ipv4:10.199.2.1
    incoming called-number .
    dtmf-relay h245-alphanumeric
    codec g711ulaw
    no vad

    dial-peer voice 11 pots
    service transfer
    destination-pattern 1300
    incoming called-number .
    port 0/1/1
    forward-digits 0

    Subject: RE: TCL script to transfer without hairpin
    Replied by: Raymond Maslanka on 19-08-2011 03:58:43 PM
    I am testing with an analog FXS card in my lab at this time, not with the T1 controller.

    "service transfer" refers to the TCL script on the inbound dial peer.

    1. Caller A on 7941 phone with DN 2015 at 10.199.2.187 dials 1300.
    2. CUCM sends call to 1300 to H.323 gateway at 192.168.1.45.
    3. Incoming voip dial peer 101 is matched.
    4. Outgoing pots dial peer 11 is matched.
    5. Call rings analog phone B on port 0/1/1.
    6. Analog phone user hookflashes, dials 2115 and hangs up and port 0/1/1 goes idle.
    7. Caller C on 7941 phone with DN 2115 at 10.199.2.188 rings, answers and call is established between A and C.
    8. Gateway at 192.168.1.45 still shows active call legs and RTP streams.

    Basically, I want to eliminate relying on the gateway at 192.168.1.45 to maintain the calls between the A and C.

    Subject: RE: TCL script to transfer without hairpin
    Replied by: Raymond Maslanka on 19-08-2011 04:18:02 PM
    Correct.  A and C are registered to CUCM.  The router at 192.168.1.45 is defined as a H.323 gateway on CUCM.  B is an FXS port / analog phone connected to gateway.

    Thank you for your prompt attention.

    Subject: RE: TCL script to transfer without hairpin
    Replied by: Yaw-Ming Chen on 19-08-2011 01:53:54 PM
    if you don't want to hair-pin using the following mode when doing leg setup

    set callInfo(mode)  REDIRECT_ROTARY

    Subject: RE: TCL script to transfer without hairpin
    Replied by: Yaw-Ming Chen on 19-08-2011 03:06:31 PM
    when did you see in "sh voip rtp con" ?

    Subject: RE: TCL script to transfer without hairpin
    Replied by: Yaw-Ming Chen on 19-08-2011 03:28:07 PM
    to 10.199.2.187
    to 10.199.2.188

    What protocol is using in this two legs ?

    Subject: RE: TCL script to transfer without hairpin
    Replied by: Yaw-Ming Chen on 19-08-2011 03:44:16 PM
    It loos something like call coming into dial-peer voice 11 pots (A caller) to B caller (10.199.2.187)

    and someone (A or initiates the transfer to C (10.199.2.188)  ? Is something like that ?

    What is the "service transfer" on dial-peer voice 101 voip for ?

    Can you please describe complete call flow ?

    Subject: RE: TCL script to transfer without hairpin
    Replied by: Yaw-Ming Chen on 19-08-2011 04:14:04 PM
    Got it, A and C are registered on CUCM right ? Will look into it.

    Subject: RE: TCL script to transfer without hairpin
    Replied by: Madhu Gindi on 23-08-2011 01:21:25 PM
    Hairpinning of call occur because of many different reasons. One of the possibility is that the GW is configured to suppress H450.
    Check your configuration under "voice service voip" and see of H450 forwards/transfer have been suppressed.