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Dec 30 / Greg

Inbound Calls Forwarded to External Numbers Won’t Pass CallerID(or Fail to Dial Out)

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This Cisco article describes the problem exactly!

The scenario:
I set my desk phone’s call forward all to forward to my cell phone. Someone from the outside calls my desk and it forwards to my cell. The number ringing on my cell phone looks like the generic PRI, and not the caller or my desk phone. For some people, the call won’t forward at all. My first step is to do a debug isdn q931 on my gateway to see what I’m presenting to the PSTN.

  • My desk line is 9793939444.
  • The outside caller is 254663555.
  • My cell phone the number is forwarded to is 9793939444.

    Debug isdn q931 with “Calling Party Selection” set to Originator:

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    ZZZ-XXX-Phone-R1#
Dec  4 08:08:50.656: ISDN Se0/1/0:23 Q931: RX <- SETUP pd = 8  callref = 0x0D93
        Bearer Capability i = 0x8090A2
                Standard = CCITT
                Transfer Capability = Speech
                Transfer Mode = Circuit
                Transfer Rate = 64 kbit/s
        Channel ID i = 0xA98381
                Exclusive, Channel 1
        Calling Party Number i = 0x2183, '2543663555'
                Plan:ISDN, Type:National
        Called Party Number i = 0xC1, '9793939444'
                Plan:ISDN, Type:Subscriber(local)
Dec  4 08:08:50.692: ISDN Se0/1/0:23 Q931: TX -> CALL_PROC pd = 8  callref = 0x8
D93
        Channel ID i = 0xA98381
                Exclusive, Channel 1
Dec  4 08:08:50.708: ISDN Se0/1/0:23 Q931: TX -> SETUP pd = 8  callref = 0x0001
        Bearer Capability i = 0x8090A2
                Standard = CCITT
                Transfer Capability = Speech
                Transfer Mode = Circuit
                Transfer Rate = 64 kbit/s
        Channel ID i = 0xA98382
                Exclusive, Channel 2
        Net Specific Fac i = 0x00E6
        Calling Party Number i = 0x2183, '2543663555'
                Plan:ISDN, Type:National
        Called Party Number i = 0x80, '9795956333'
                Plan:Unknown, Type:Unknown
        Redirecting Number i = 0x00008F, '4444'
                Plan:Unknown, Type:Unknown
ZZZ-XXX-Phone-R1#
Dec  4 08:08:50.796: ISDN Se0/1/0:23 Q931: RX <- STATUS pd = 8  callref = 0x8001
 
        Cause i = 0x82E46C74 - Invalid information element contents
        Cause i = 0x82AB6C74 - Access information discarded
        Call State i = 0x01
Dec  4 08:08:50.800: ISDN Se0/1/0:23 Q931: RX <- CALL_PROC pd = 8  callref = 0x8
001
        Channel ID i = 0xA98382
                Exclusive, Channel 2
ZZZ-XXX-Phone-R1#debug isdn q931
Dec  4 08:08:51.950: ISDN Se0/1/0:23 Q931: RX <- PROGRESS pd = 8  callref = 0x80
01
        Progress Ind i = 0x8488 - In-band info or appropriate now available
Dec  4 08:08:51.954: ISDN Se0/1/0:23 Q931: TX -> PROGRESS pd = 8  callref = 0x8D
93
        Progress Ind i = 0x8488 - In-band info or appropriate now available

    As you can see in the debug above, the call heading back out the gateway is set to the outside caller’s phone number. Generally the Calling Party Selection(CPS) is set to Originator. What this means is that when a call is forwarded, it will appear to be coming from the calling party’s number. This is where our problem lies. When someone calls my desk from outside and the call is then forwarded back out the PSTN, the phone number will appear to come from a number that shouldn’t be sourced from my PRI. What I can do is set the CPS so that it will change the source number to be the first forwarded device.
    Device -> Gateway -> Outbound section -> "Calling Party Selection"

    Now, have a look at our debug.

    Debug isdn q931 with “Calling Party Selection” set to First Redirect Number (External):

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    ZZZ-XXX-Phone-R1#
Dec  4 08:10:47.143: ISDN Se0/1/0:23 Q931: RX <- SETUP pd = 8  callref = 0x0D94
        Bearer Capability i = 0x8090A2
                Standard = CCITT
                Transfer Capability = Speech
                Transfer Mode = Circuit
                Transfer Rate = 64 kbit/s
        Channel ID i = 0xA98381
                Exclusive, Channel 1
        Calling Party Number i = 0x2183, '2543663555'
                Plan:ISDN, Type:National
        Called Party Number i = 0xC1, '9793939444'
                Plan:ISDN, Type:Subscriber(local)
Dec  4 08:10:47.179: ISDN Se0/1/0:23 Q931: TX -> CALL_PROC pd = 8  callref = 0x8
D94
        Channel ID i = 0xA98381
                Exclusive, Channel 1
Dec  4 08:10:47.195: ISDN Se0/1/0:23 Q931: TX -> SETUP pd = 8  callref = 0x0001
        Bearer Capability i = 0x8090A2
                Standard = CCITT
                Transfer Capability = Speech
                Transfer Mode = Circuit
                Transfer Rate = 64 kbit/s
        Channel ID i = 0xA98382
ZZZ-XXX-Phone-R1#
                Exclusive, Channel 2
        Net Specific Fac i = 0x00E6
        Calling Party Number i = 0x2180, '9793939444'
                Plan:ISDN, Type:National
        Called Party Number i = 0x80, '9795956333'
                Plan:Unknown, Type:Unknown
        Redirecting Number i = 0x00008F, '4444'
                Plan:Unknown, Type:Unknown
Dec  4 08:10:47.279: ISDN Se0/1/0:23 Q931: RX <- STATUS pd = 8  callref = 0x8001
 
        Cause i = 0x82E474 - Invalid information element contents
        Cause i = 0x82AB74 - Access information discarded
        Call State i = 0x01
Dec  4 08:10:47.287: ISDN Se0/1/0:23 Q931: RX <- CALL_PROC pd = 8  callref = 0x8
001
        Channel ID i = 0xA98382
                Exclusive, Channel 2
Dec  4 08:10:48.140: ISDN Se0/1/0:23 Q931: RX <- PROGRESS pd = 8  callref = 0x80
01
        Progress Ind i = 0x8488 - In-band info or appropriate now available
Dec  4 08:10:48.148: ISDN Se0/1/0:23 Q931: TX -> PROGRESS pd = 8  callref = 0x8D
94
        Progress Ind i = 0x8488 - In-band info or appropriate now available

    When the call heads out to the PSTN now, it looks like it is sourced from my desk phone. Now the call will go through and I will be able to see that it is coming from my desk.

    • Filed under CallManager, Cisco, VOIP
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