IM JUST LOST ON THIS ONE (GURUS HELP Please)

Unanswered Question
Feb 19th, 2008

Hi everyone,

CCM4.1

2811 GW using MGCP (newly migrated from H323 to MGCP).

All Inbound and Outbound Calls works fine. The Problem we are facing is that our user are experiencing a one-way-voice when calling Hotlines that belongs to ONE Specific Partner Company. They have more than 100 Hotlines. We only have this problem with this ONE company.

All Calls goes through through our E1 PRIs to the PSTN then to an IVR (with voice recognition) of that company, after a User choose the option he wants (speak to an Agent), they get transfered to the Agent, when the Agents picks up the phone, we can hear him but he can't hear us. The Problem is very SPROADIC, say 30% of calls to those hotlines experience this problem the rest 70% went fine.

I mostly checked everything related to one way voice. I still don't have a clue what this might be.

Our Partner Company says everything is fine on their side and that we should digg deeper for the problem on our side.

1- When on Phone i double click "?" and see that Packets are increasing both RX and TX.

2- the debug isdn q931 showed me nothing.

3- i tried debug voice rtp, but the Debugging made the Call completly inaudible, so when the IVR tell me to say something, it can't recognise what im saying while im in Debugging mode (only one call at that time was made on that gateway).

4- Callmanager traces: Nothing!!!.

5- show controller e1 show no slip errors or whatever,

Im really lost here guys and need some Guru advice. Thanks.

Here is the GW config:

hostname XXXXXXXXXXXXXX

!

network-clock-participate wic 0

no network-clock-participate aim 0

no network-clock-participate aim 1

network-clock-select 1 E1 0/0/0

no aaa new-model

ip subnet-zero

ip cef

!

!

no ftp-server write-enable

isdn switch-type primary-net5

isdn voice-call-failure 0

!

voice-card 0

dspfarm

dsp services dspfarm

!

voice call convert-discpi-to-prog

voice rtp send-recv

!

voice service voip

fax protocol pass-through g711alaw

modem passthrough nse codec g711alaw

!

voice class codec 1

codec preference 1 g711ulaw

codec preference 2 g711alaw

codec preference 3 g729r8

codec preference 4 g729br8

!

ccm-manager redundant-host (Pub IP)

ccm-manager mgcp

no ccm-manager fax protocol cisco

ccm-manager music-on-hold

ccm-manager config server (PUB IP)

ccm-manager config

!

!

controller E1 0/0/0

pri-group timeslots 1-31 service mgcp

!

controller E1 0/0/1

pri-group timeslots 1-31 service mgcp

!

interface FastEthernet0/0

ip address X.X.X.X

ip directed-broadcast

duplex full

speed 100

no keepalive

h323-gateway voip interface

h323-gateway voip bind srcaddr X.X.X.X

!

interface Serial0/0/0:15

no ip address

isdn switch-type primary-net5

isdn overlap-receiving

isdn incoming-voice voice

isdn bind-l3 ccm-manager

isdn sending-complete

no cdp enable

!

interface Serial0/0/1:15

no ip address

isdn switch-type primary-net5

isdn overlap-receiving

isdn incoming-voice voice

isdn bind-l3 ccm-manager

isdn sending-complete

no cdp enable

!

ip classless

ip route xxxxxxx

!

!

voice-port 0/0/0:15

cptone DE

!

voice-port 0/0/1:15

cptone DE

!

mgcp

mgcp call-agent (IP Subscriber) 2427 service-type mgcp version 0.1

mgcp dtmf-relay voip codec all mode out-of-band

mgcp rtp unreachable timeout 1000 action notify

mgcp modem passthrough voip mode nse

mgcp modem passthrough voip codec g711alaw

mgcp package-capability rtp-package

no mgcp package-capability res-package

mgcp package-capability sst-package

no mgcp package-capability fxr-package

no mgcp timer receive-rtcp

mgcp sdp simple

mgcp fax t38 inhibit

mgcp rtp payload-type g726r16 static

mgcp bind control source-interface FastEthernet0/0

mgcp bind media source-interface FastEthernet0/0

!

mgcp profile default

!

!

dial-peer voice 1 pots

application mgcpapp

direct-inward-dial

port 0/0/0:15

!

!

dial-peer voice 2 pots

application mgcpapp

port 0/0/1:15

I have this problem too.
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banetirado Tue, 02/19/2008 - 13:58

I have experienced a lot of one way audio loss and the problem (in our case) is the way the traffic is being handled by the firewall. Have you had your security engineer on both ends look at the traffic?

pcameron Tue, 02/19/2008 - 14:14

If these problem calls are only with one particular number on the PSTN, there is likely a difference in the Q931 messages that come in. The most common reason is some kind of progress IE that indicates in band audio - it's hard to be more specific than this without some Q931 traces. I would suggest you get two logs - one for a call to a good number and the other log for the number that has the problem. If it takes a while to have a failing call, make sure you also include a trace that shows the WORKING call to the number as well. Edit the debugs so you only show the good/bad logs ... No one likes wading through excessive trace files.

Secondly, I notice in your config you have 'application mgcpapp' under your POTS dial peers. This is not needed and can cause many 'weird' issues - the MGCP is already enabled by the command 'pri-group timeslots 1-31 service mgcp' and 'isdn bind-l3 ccm-manager' , so configuring the service under the dial peer causes a second ISDN stack to start up and it can cause problems interacting with the rest of the software. Remove 'application mgcpapp' off the dial peers !!!!!

The other thing is that since you are using the CLI syntax of 'application mgcpapp', this is an older release of code. Without any scientific basis for this recommendation , I would suggest you try loading the latest 12.4 mainline (non T) release of IOS onto the router and see if that helps as well. For voice, latest is generally the best.

Jayd000007 Wed, 02/20/2008 - 03:08

Thank you Cameron, i will try that with disabling the "application mgcpapp" and maybe then do an IOS upgrade, hopefully this will fix it. I will post again in a few Days.

cogginrl Fri, 02/22/2008 - 01:03

Had a similar problem the other day! Try altering the Mgcp bind statement to the voice vlan sub interface. It worked for me.

Jayd000007 Fri, 02/22/2008 - 01:26

@COGGIN

you mean this two commands:

mgcp bind control source-interface FastEthernet0/0

mgcp bind media source-interface FastEthernet0/0

what do you mean with altering them to the Voice VLAN interface???

Jayd000007 Fri, 02/22/2008 - 01:27

@pcameron

I did remove the application mgcpapp, but it didn't work. I will Upgrade the IOS to 13.4 next week.

dandrools Wed, 04/09/2008 - 09:29

I think what he was getting at is to make sure the mgcp bind commands point to an interface with an address in a voice vlan for which QoS has been configured.

A lot of people like to use Loopback interfaces for the bind commands, given that they are always in an *up* state.

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