Q.931 is backhauled to CCM MANAGER

[Muhammad Jawwad Habib]

Dears,

I am having issue with the ISDN. I cannot see debug isdn q931.

S2811#show isdn status

Global ISDN Switchtype = primary-net5

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

ISDN Serial0/1/0:15 interface

        dsl 0, interface ISDN Switchtype = primary-net5

        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 0 CCBs = 0

    The Free Channel Mask:  0x80000007

    Number of L2 Discards = 0, L2 Session ID = 1

    Total Allocated ISDN CCBs = 0

[Chris Deren]

debug Q931 still works with MGCP backhauled D-channel.  What is not working for you?

Chris

[Muhammad Jawwad Habib]

I cannot see any debug output for q931

I can see for others like Q921

[Jaime Valencia]

Have you enabled term mon before enabling the debugs??

HTH

java

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[Muhammad Jawwad Habib]

For sure I have done it

[Gordon Ross]

Have you got any left-over "debug cond"s lurking ? That's caught me out once or twice before.

GTG

[neil.woolloff]

Hello,

But did you ever get to the bottom of this?

encountering same issue and cannot understand why.

term mon - def enabled

logging is at debug level - still nothing

u all - done prior to entering debug isdn q931 so knew nothing else would interfere

nothing shows when we do:

show isdn active

show isdn history

show isdn service

all these show no information at all, only the column heading information.

ios os 15.13t2 on a 2821

Thanks

[Gordon Ross]

Neil Wooloff wrote:
encountering same issue and cannot understand why.
term mon - def enabled
logging is at debug level - still nothing
u all - done prior to entering debug isdn q931 so knew nothing else would interfere

What about "sh debug cond" ?

nothing shows when we do:
show isdn active
show isdn history
show isdn service
all these show no information at all, only the column heading information.

That's all you'll get for MGCP back-hauled ISDN. The gateway doesn't know anything about calls as it never sets them up...

GTG

[Aaron Harrison]

Hi All

To clarify - debug isdn q931 does definately work on MGCP.

I've only seen it not work once, that was an IOS 15 release that decided to show me hex instead of the decoded output. I strongly suspect that the folks not seeing output (assuming you can see debug output from other commands, and therefore don't have a simple ssh/telnet session problem, and that you have followed Gordon's advice (+5) and checked someone hasn't filtered the debug with conditions) are hitting some sort of bug. That was my issue, and an update fixed it after a lot of 'is this a new IOS 15.0 feature?' head scratching  :-)

Aaron