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Community Member

VoIP ISDN layer 2 bounces

I am new to VoIP.

We have a voice system and on of our branches will periodically loose their system.

I can see on the router that layer 2 is bouncing.

The branches have a seperate PRI for voice.

Would this be a carrier issue?

Below is what I am seeing on the interface, it will go 20 minutes with no problem, then a few days, then it will happen again.

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

y

ISDN Serial0/0/0:23 interface

dsl 0, interface ISDN Switchtype = primary-ni

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: 0x807FFFFF

Number of L2 Discards = 0, L2 Session ID = 167

Total Allocated ISDN CCBs = 0

2811-01#sh isdn stat

Global ISDN Switchtype = primary-ni

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

y

ISDN Serial0/0/0:23 interface

dsl 0, interface ISDN Switchtype = primary-ni

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 = TIMER_RECOVERY

Layer 3 Status:

0 Active Layer 3 Call(s)

Active dsl 0 CCBs = 0

The Free Channel Mask: 0x807FFFFF

Number of L2 Discards = 0, L2 Session ID = 227

--More--

001772: Aug 23 09:26:53 EDT: %ISDN-6-LAYER2DOWN: Layer 2 for Interface Se0/0/0:2

3, TEI 0 changed to down

001773: Aug 23 09:26:54 EDT: %ISDN-6-LAYER2UP: Layer 2 for Interface Se0/0/0:23,

TEI 0 cha Total Allocated ISDN CCBs = 0

2811-01#sh isdn stat

Global ISDN Switchtype = primary-ni

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

y

ISDN Serial0/0/0:23 interface

dsl 0, interface ISDN Switchtype = primary-ni

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 = AWAITING_ESTABLISHMENT

Layer 3 Status:

0 Active Layer 3 Call(s)

Active dsl 0 CCBs = 0

The Free Channel Mask: 0x807FFFFF

Number of L2 Discards = 0, L2 Session ID = 232

Total Allocated ISDN CCBs = 0

2811-01#sh isdn stat

Global ISDN Switchtype = primary-ni

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

y

ISDN Serial0/0/0:23 interface

dsl 0, interface ISDN Switchtype = primary-ni

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 = TIMER_RECOVERY

Layer 3 Status:

0 Active Layer 3 Call(s)

Active dsl 0 CCBs = 0

The Free Channel Mask: 0x807FFFFF

Number of L2 Discards = 0, L2 Session ID = 236

Total Allocated ISDN CCBs = 0

2811-01#sh isdn stat

Global ISDN Switchtype = primary-ni

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

y

3 REPLIES
Community Member

Re: VoIP ISDN layer 2 bounces

run "debub isdn q921" and upload the messages when layer-2 is down.

Community Member

Re: VoIP ISDN layer 2 bounces

Any ideas what could have been going on?

Here is what fixed the problem:

"We pushed the config from the GW to the Call manager and also told the GW to pull it?s config from the CM.

Then reset the gateway within Call manager.

We entered these commands on the gateway, reseting the gateway by itself didn?t work.:

ccm-manager config

ccm-manager config server 10.250.10.1"

Community Member

Re: VoIP ISDN layer 2 bounces

hello dear ,

run "deb isdn q921",

"sh isdn timer " when l-2is down and post it .

can u attch the running config aswell.

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