Understanding MGCP Gateway Fallback Process

Fatty · ‎06-13-2018

I'm hoping some of you smart folks can help me understand what I'm seeing here.

This is what I have configured.

CM 11.5 >>>> SIP Trunk >>>> Cisco 4331 ( QSIG T1 From Avaya)

What I'm seeing is...

1. Layer 1 is UP

2. Layer 2 ( Q.921 Sig shows no RX from remote Avaya)

3. SIP trunk to 4331 is UP

4. D Channel on Avaya is down

I guess I'm lacking something basic here, since this is not an MGCP gateway, I don't have the option to bind l-3 and really not sure how this circuit is supposed to look from a "sh isdn st" command. I can provide all the necessary config etc, but did not want to post a novel here if I'm trying to do something fundamentally wrong.

I have done plenty of MGCP installations with T1 / E1 etc..very simple. I think what is confusing me is the QSIG over SIP.

R0g22 · ‎06-14-2018

There is no dependability of call manager in this case, no l3 binds required.
ISDN status should show layer 1 as active and layer 2 as multiple frame established to be able
to receive calls on isdn layer 3.

Post an output for show isdn status here. Also enable “debug isdn q921” and shut/no shut the controller and add the output here. We should be able to see why is the d-channel down.

In addition to the above, have you made sure line coding, framing and switch type are correct on both avaya and ios gw ?

Fatty · ‎06-14-2018

Hi, Thanks for taking the time to look at this. As requested, the attached
word doc contains the following output

1. sh inv
2. sh isdn st 0/1/1
3. sh controller t1
4. debug isdn q921

I assume all the routing for these channels is done in dial-peers...yes?

Again, thanks for taking the time here.

Fatty · ‎06-14-2018

It looks as though the doc was stripped...here is the txt

sh inventory – 4331 ISR

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

AME: "Chassis", DESCR: "Cisco ISR4331 Chassis"

PID: ISR4331/K9 , VID: V04 , SN: FLM2209V1N6

NAME: "Power Supply Module 0", DESCR: "250W AC Power Supply for Cisco ISR 4330"

PID: PWR-4330-AC , VID: V02 , SN: PST2147N2KT

NAME: "module 0", DESCR: "Cisco ISR4331 Built-In NIM controller"

PID: ISR4331/K9 , VID: , SN:

NAME: "NIM subslot 0/1", DESCR: "NIM-2MFT-T1/E1 - T1/E1 Serial Module"

PID: NIM-2MFT-T1/E1 , VID: V05 , SN: FOC21502UPK

NAME: "subslot 0/1 db module 0", DESCR: "PVDM4-64 Voice DSP Module"

PID: PVDM4-64 , VID: V02 , SN: FOC22051AC3

NAME: "NIM subslot 0/0", DESCR: "Front Panel 3 ports Gigabitethernet Module"

PID: ISR4331-3x1GE , VID: V01 , SN:

NAME: "module 1", DESCR: "Cisco ISR4331 Built-In SM controller"

PID: ISR4331/K9 , VID: , SN:

NAME: "module R0", DESCR: "Cisco ISR4331 Route Processor"

PID: ISR4331/K9 , VID: V04 , SN: FDO22033JVW

NAME: "module F0", DESCR: "Cisco ISR4331 Forwarding Processor"

PID: ISR4331/K9 , VID: , SN:

sh isdn st - 0/1/1

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

Global ISDN Switchtype = primary-ni

ISDN Serial0/1/1:23 interface

******* Network side configuration *******

dsl 1, interface ISDN Switchtype = primary-qsig

**** Master side configuration ****

Layer 1 Status:

ACTIVE

Layer 2 Status:

TEI = 0, Ces = 1, SAPI = 0, State = AWAITING_ESTABLISHMENT

Layer 3 Status:

0 Active Layer 3 Call(s)

Active dsl 1 CCBs = 0

The Free Channel Mask: 0x807FFFFF

Number of L2 Discards = 0, L2 Session ID = 221

Total Allocated ISDN CCBs = 0

sh controller t1

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

T1 0/1/1 is up

Applique type is Channelized T1

Cablelength is long gain36 0db

Description: - QSIG Circuit to Avaya G450

No alarms detected.

alarm-trigger is not set

Soaking time: 3, Clearance time: 10

AIS State:Clear LOS State:Clear LOF State:Clear

Framing is SF, Line Code is B8ZS, Clock Source is Line.

BER thresholds: SF = 10e-3 SD = 10e-6

Data in current interval (681 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 24 hours)

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

Q921 debug

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

Jun 14 15:08:38.728: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:08:39.729: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:08:40.729: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:08:41.729: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:08:47.730: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:08:48.731: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:08:49.730: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:08:50.731: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:08:56.733: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:08:57.733: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:08:58.733: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:08:59.734: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:09:05.736: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:09:06.735: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:09:07.736: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

Jun 14 15:09:08.735: ISDN Se0/1/1:23 Q921: Net TX -> SABMEp sapi=0 tei=0

R0g22 · ‎06-15-2018

I don’t see a “Uaf” coming back from Avaya to bring up the d-channel.
On the controller the framing you have is SF rather than ESF, is that supposed to be like that ?

Check the cable. You should be using a PRI crossover utilising 1,2,4,5 pins only. And check in Avaya.