BRI MGCP backhaul

[caiacamina]

Hi everyone,

We have a solution of CUCMA Business ver6.1.2 wih a Voice Gateway 2851, integrated by MGCP. We have one PRI for public telephony and 4 FXO for GSM; so while everthing is working, but the analogue lines sometimes have an unxpected behaviour.We decided to migrate from FXO modems to BRI for the GSM connection. The card is VIC2-2BRI-NT/TE; the BRI is registered with the call manager, I have the translation pattern defined to terminate the calls inside, but the inbound calls are dropped between the modem and the gateway; I listen 2 to ring tones and than the call is dropped;

Here the partial configuration:

!

interface BRI0/3/0
no ip address
isdn switch-type basic-net3
isdn point-to-point-setup
isdn incoming-voice voice
isdn bind-l3 ccm-manager service mgcp
isdn static-tei 0
!

voice-port 0/3/0
compand-type a-law
cptone PT
!        
dial-peer voice 4000 pots
service mgcpapp
port 0/3/0
forward-digits all
!   

-----------------------------------------------------------------------------------------------

ISDN STATUS

    
   VGW_SEDE#sh isdn status brI 0/3/0
Global ISDN Switchtype = primary-net5

%Q.931 is backhauled to CCM MANAGER 0x0003 on DSL 6. Layer 3 output may not apply

ISDN BRI0/3/0 interface
    dsl 6, interface ISDN Switchtype = basic-net3
    L2 Protocol = Q.921 0x0000  L3 Protocol(s) = CCM MANAGER 0x0003
    Layer 1 Status:
    ACTIVE
    Layer 2 Status:
    TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED
    Layer 3 Status:
    0 Active Layer 3 Call(s)
    Active dsl 6 CCBs = 0
    The Free Channel Mask:  0x80000003
    Total Allocated ISDN CCBs = 0
VGW_SEDE#

-----------------------------------------------------------------------------------------------------------

Q931 deb

VGW_SEDE#
*Feb 10 10:22:24.513: ISDN BR0/3/0 Q931: RX <- SETUP pd = 8  callref = 0x01
    Bearer Capability i = 0x8090A3
        Standard = CCITT
        Transfer Capability = Speech 
        Transfer Mode = Circuit
        Transfer Rate = 64 kbit/s
    Channel ID i = 0x89
    Calling Party Number i = 0xA1, '820889311'
        Plan:ISDN, Type:National
*Feb 10 10:22:28.485: ISDN BR0/3/0 Q931: RX <- SETUP pd = 8  callref = 0x01
    Bearer Capability i = 0x8090A3
        Standard = CCITT
        Transfer Capability = Speech 
        Transfer Mode = Circuit
        Transfer Rate = 64 kbit/s
    Channel ID i = 0x89
    Calling Party Number i = 0xA1, '820889311'
        Plan:ISDN, Type:National
*Feb 10 10:22:32.457: ISDN BR0/3/0 Q931: RX <- DISCONNECT pd = 8  callref = 0x01
    Cause i = 0x8092 - No user responding
*Feb 10 10:22:32.461: ISDN BR0/3/0 Q931: TX -> RELEASE_COMP pd = 8  callref = 0x81
    Cause i = 0x80D1 - Invalid call reference value
----------------------------------------------------------------------------------------------------------------------

Q921 deb

VGW_SEDE#
*Feb 10 10:28:31.077: ISDN BR0/3/0 Q921: User RX <- RRp sapi=0 tei=0 nr=4
*Feb 10 10:28:31.081: ISDN BR0/3/0 Q921: User TX -> RRf sapi=0 tei=0 nr=12
*Feb 10 10:28:41.041: ISDN BR0/3/0 Q921: User RX <- RRp sapi=0 tei=0 nr=4
*Feb 10 10:28:41.041: ISDN BR0/3/0 Q921: User TX -> RRf sapi=0 tei=0 nr=12
*Feb 10 10:28:51.001: ISDN BR0/3/0 Q921: User RX <- RRp sapi=0 tei=0 nr=4
*Feb 10 10:28:51.001: ISDN BR0/3/0 Q921: User TX -> RRf sapi=0 tei=0 nr=12
*Feb 10 10:28:55.469: ISDN BR0/3/0 Q921: User RX <- INFO sapi=0 tei=0, ns=12 nr=4
*Feb 10 10:28:55.469: ISDN BR0/3/0 Q921: User TX -> RR sapi=0 tei=0 nr=13
*Feb 10 10:28:59.437: ISDN BR0/3/0 Q921: User RX <- INFO sapi=0 tei=0, ns=13 nr=4
*Feb 10 10:28:59.441: ISDN BR0/3/0 Q921: User TX -> RR sapi=0 tei=0 nr=14
*Feb 10 10:29:03.409: ISDN BR0/3/0 Q921: User RX <- INFO sapi=0 tei=0, ns=14 nr=4
*Feb 10 10:29:03.413: ISDN BR0/3/0 Q921: User TX -> RR sapi=0 tei=0 nr=15
*Feb 10 10:29:03.413: ISDN BR0/3/0 Q921: User TX -> INFO sapi=0 tei=0, ns=4 nr=15
*Feb 10 10:29:03.441: ISDN BR0/3/0 Q921: User RX <- RR sapi=0 tei=0 nr=5

---------------------------------------------------------------------------------------------------------------------------

I'm very thanks in advance for any idea to solve this problem.

[Thomas Dominic · Accepted solution]

*Feb 10 10:22:32.457: ISDN BR0/3/0 Q931: RX <- DISCONNECT pd = 8  callref = 0x01 
    Cause i = 0x8092 - No user responding
*Feb 10 10:22:32.461: ISDN BR0/3/0 Q931: TX -> RELEASE_COMP pd = 8  callref = 0x81 
----------------------------------------------------------------------------------------------------------------------

From the isdn q931 debug it is very clear that the telco is sending the disconnect;

The reason shown is that No user responds; if this is after 2 rings, you need to speak to them about this to increase the wait time before they disconnect this call(just show them this debug ).

Regards

Thomas

P.S. Please rate helpful posts

[caiacamina]

Thanks Thomas,

I agree with you, but when the modem disconnect the call because no user responding, the gateway returns the following error:

*Feb 10 12:31:28.436: ISDN BR0/3/0 Q931: TX -> RELEASE_COMP pd = 8  callref = 0x81
    Cause i = 0x80D1 - Invalid call reference value

What does this mean?

According to the configuration posted, is there any parameter that must be changed/added/removed on the gateway?

Regards

Caiacamina

[Thomas Dominic]

This means that the G/W has  received a message with a call reference which is not currently in use  on the user-network interface.

http://www.cisco.com/en/US/docs/ios/12_3/vvf_c/voice_troubleshooting/old/vts_appa.html

this is a document of common disconnect codes. This explains the same

[vasank]

what do you mean by terminates between modem and gateway how exactly the call is flowing and what is the endpoint here analog phone GSM mobile phone or an IP phone..?

[caiacamina]

Hi,

Thanks a lot,

The modem is connected to a BRI interface (VIC2-2BRI-NT/TE) on a cisco gateway; the gateway is conneted to a Call Manager; the protocol is MGCP. I think the problem is with the modem or with the voice card, I got the configurtion interface of the modem and I'm checking what can be causing the issue, because when I call to the SIM card number on the GSM modem, it tries to stablish the call (when rings 2 times) and then drops the call (with the message 'no user responding'). I have a translation patern on the Call Manager that redirect the call for one internal number and it also rings 2 times inside, but drops after.

[caiacamina]

Hi,

The problem is solved. It was related to Cisco IOS. Using the version c2800nm-spservicesk9-mz.124-22.T5.bin the calls are normal placed (in and out)

For MGCP BRI backhaul with the model 2851 the IOS shoul start from 12.4(2)T and I was using another IOS without the proper voice features for this funcionality.

Thanks for your attention