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Community Member

D Channel Out Of Service

Hi,

can any1 tell me how to troubleshoot "D Channel Out Of Service" error reported in cuom, i  have mgcp controlled gw, with cucm 7.0.2. Ireceive this error ocassionally.

Detailed error is

D Channel Out Of Service::Component=x.x.x.x-System-[Id#1270357456318];Device IP address=x.x.x.x;Device Name.=S1/DS1-0#PRIGW;Unique channel Id=S1/DS1-0#PRIGW:16 Reason.:0;Channel Id.=16;

any help is appreciated...

13 REPLIES

Re: D Channel Out Of Service

I am assuming that you see the B-channels go out of service for the E1 as well. As the error indicates, a loss in service was encountered on the D-channel. This could have been a physical layer issue, the carrier's network, or an issue with the network path between the CUCM and voice gateway (up to and including a gateway reset).

Some things to check:

1. Physical Layer- ISDN: "show controller e1 1/1". See if you are taking any hits on the line. You may also want to enable SNMP traps for link change events on the controller using the "snmp trap link-status". You may want to do this on your Ethernet interfaces on the gateway device and the attached switch (if possible). If it is a recurring problem you may be able to use traps from the interfaces to narrow down the suspect area.

2. Check Uptime: "show version". Check the gateway to ensure it hasn't been reset (normally or abnormally) at times that correspond with your last D_channel OOS message.

3. Check your CUCM syslogs to see if you see any devices failing over/failing back between your call processing nodes (just to see if you have any network path issues to/from the CUCM primary call processor).

4. If your gateway is assigned directly to route patterns (i.e. no route groups/route lists used) then any change to a route pattern will cause the D- and B- channels to cycle on the gateway. Worth checking.

In general you should try to trend the issue to see if it is always one gateway (if you have more than one). You should also try to see if there is a trend with time, day of week, etc.

You may be able to correlate data with your carrier. Some of them are a pain to deal with when trying to troubleshoot issues like this. But, in my experience it isn't uncommon to see a D-channel flap at 02:00 hours because the carrier did a switch upgrade or some other change in the "magical" cloud.

HTH.

Regards,

Bill

HTH -Bill (b) http://ucguerrilla.com (t) @ucguerrilla

Please remember to rate helpful responses and identify

Community Member

Re: D Channel Out Of Service

hi bell,

link status logging is already enabled, so as ucm syslog option thats y m getting alert in my cuom 2.x server. but reason is still hidden. below is my e1 output which clearly shows that network side (telco) is ok. Also i onlt get d channel down message nothing about b channels.

mgcpGW#sh version
Cisco IOS Software, 2800 Software (C2800NM-IPVOICE-M), Version 12.4(15)T7, RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2008 by Cisco Systems, Inc.
Compiled Wed 13-Aug-08 17:09 by prod_rel_team

ROM: System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)

mgcpGW uptime is 24 weeks, 3 days, 1 hour, 2 minutes

mgcpGW#sh controller E1
E1 1/0 is up.
  Applique type is Channelized E1 - balanced
  No alarms detected.
  alarm-trigger is not set
  Version info Firmware: 20071011, FPGA: 255, spm_count = 0
  Framing is NO-CRC4, Line Code is HDB3, Clock Source is Line.
  Current port master clock:recovered from backplane
  Data in current interval (36 seconds elapsed):
     0 Line Code Violations, 0 Path Code Violations
     0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
  Total Data (last 10 15 minute intervals):
     0 Line Code Violations, 0 Path Code Violations,
     0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
E1 1/1 is administratively down. (not required)

Re: D Channel Out Of Service

Some times it is something simply in the serial interface commands.   Check to make sure the ccm commands are located in the serial interface.  THey like to disappear randomly when you are doing work on the router i have noticed.  

Also do a no mgcp.  wait for it to tear down.  then do a mgcp statement. 

Do show ccm-manager

It will give what state the registration is in.

Also, if its the only MGCP gateway having issues, possibly restart the media services on CUCM.

Community Member

Re: D Channel Out Of Service

Regardless of doing no mgcp & mgcp, this issue happens once a week,

further please find show output below

mgcpGW#sh ccm
MGCP Domain Name: mgcpGW
Priority        Status                   Host
============================================================
Primary         Registered               1.1.1.2
First Backup    Backup Ready             1.1.1.3
Second Backup   Backup Ready             1.1.1.1

Current active Call Manager:    10.1.1.2
Backhaul/Redundant link port:   2428
Failover Interval:              30 seconds
Keepalive Interval:             15 seconds
Last keepalive sent:            00:50:25 GMT Apr 6 2010 (elapsed time: 00:00:05)
Last MGCP traffic time:         00:50:25 GMT Apr 6 2010 (elapsed time: 00:00:05)
Last failover time:             20:42:22 GMT Oct 23 2009 from (10.103.1.12)
Last switchback time:           20:55:22 GMT Oct 23 2009 from (10.103.1.13)
Switchback mode:                Graceful
MGCP Fallback mode:             Not Selected
Last MGCP Fallback start time:  None
Last MGCP Fallback end time:    None
MGCP Download Tones:            Disabled
TFTP retry count to shut Ports: 2

Backhaul Link info:
    Link Protocol:      TCP
    Remote Port Number: 2428
    Remote IP Address:  10.1.1.2
    Current Link State: OPEN
    Statistics:
        Packets recvd:   791030
        Recv failures:   0
        Packets xmitted: 1018207
        Xmit failures:   0
    PRI Ports being backhauled:
        Slot 1, port 0
Configuration Auto-Download Information
=======================================
Current version-id: 1255435240-7186f77e-28c0-4cf2-a5ca-e8ede3e92b5c
Last config-downloaded:00:00:00
Current state: Waiting for commands
Configuration Download statistics:
        Download Attempted             : 12
          Download Successful          : 12
          Download Failed              : 0
          TFTP Download Failed         : 26
        Configuration Attempted        : 2
          Configuration Successful     : 2
          Configuration Failed(Parsing): 0
          Configuration Failed(config) : 0
Last config download command: New Registration
FAX mode: cisco
Configuration Error History:

************************************

mgcpGW#sh run int s1/0:15

Current configuration : 191 bytes
!
interface Serial1/0:15
no ip address
encapsulation hdlc
logging event nfas-status
isdn switch-type primary-net5
isdn incoming-voice voice
isdn bind-l3 ccm-manager
no cdp enable
end

Re: D Channel Out Of Service

Do you have this trunk configured for nfas? I don't think nfas is supported in MGCP mode. I am offline presently and can't double check. I am basing my question on the logging event nfas-status config on your serial interface.

HTH -Bill (b) http://ucguerrilla.com (t) @ucguerrilla

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Re: D Channel Out Of Service

Back online.  Double checked and NFAS isn't supported in MGCP mode.  Now, I am not certain how "unsupported" it is myself as I have never tried to turn it on in MGCP mode to see in what manner it affects things.  I also don't know if you have NFAS enabled as I was just guessing based on one of your posts.

If you are doing NFAS on the PRI configured for MGCP, then it isn't supported.

If you are not, then we are back to square one.

If you are and you need NFAS support, then you will need to switch to H323 or SIP.

HTH.

Regards,
Bill

HTH -Bill (b) http://ucguerrilla.com (t) @ucguerrilla

Please remember to rate helpful responses and identify

Community Member

Re: D Channel Out Of Service

if m not wring then nfas is for "If more than 01 pri uses same d channel for signaling". but i have separate pri that is using its own d channel.

Re: D Channel Out Of Service

Your description of NFAS is correct. You can disregard my line of questioning.

Regards,

Bill

HTH -Bill (b) http://ucguerrilla.com (t) @ucguerrilla

Please remember to rate helpful responses and identify

Community Member

Re: D Channel Out Of Service

Hi Guys,

Is there any solution for this problem, please lemme know....

Cisco Employee

Re: D Channel Out Of Service

The D channel will go down in any of the following circumstances:

* There is a L2 (q921) issue on the PRI between the gateway and the provider.

* MGCP messages are dropped between the gateway and CM.  This could be either UDP/2427 or TCP/2428.  Make sure signaling traffic is not placed in a priority queue anywhere, as it can burst and starve the flow.  If you have MPLS, if your provider has a separate non-realtime queue, put it there.  Otherwise, use the default queue and strip DSCP.

* Someone clicks 'reset gateway' on CM, or does an action on another device in CM which also resets the route group/device.

If you can get the followind during an event, it would shed more light:

debug mgcp pack

debug ip tcp trans

debug isdn q921

debug isdn q931

Also get detailed CM traces during the time of the issue.  Note the time the issue occurs.  Collect 'sh policy-map int' if any WAN routers are involved.

Community Member

Re: D Channel Out Of Service

thx for detailing me the steps, i will check this & let you know the outcomes. Could you please tell me which CM traces i have to enable????

Cisco Employee

Re: D Channel Out Of Service

Turning on the default parameters for the 'detailed' level of CM traces should be fine.

Community Member

Re: D Channel Out Of Service

wot exact ""default parameters''??

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