One Way Audio issue over WAN ( VPN Tunnel) with CUCM 7.1(5)

[murthy2005]

Hi,

We are facing one way audio issues from branch to HQ over WAN.

CUCM 7.1 is located in HQ and is connecting to the PSTN and WAN locations.

All branch phones ( 8 Phones ) are getting registered in HQ .

DMVPN  is being configured between HQ and branch .

QOS is configured in branch  router and swicthes, no packet drop was seen anywhere in branch router.

The call flow is like this ,

HQ ip Phone--> HQ CUCM7.1 --> Cisco ASA--->Cisco3800 HQWAN Rtr-->( 10 Mbps)--> MPLS-->(512 Kbps)-- Cisco 2811 WAN Rtr ---> IP Phone.

When Branch IP Phone Calls HQ  IP Phone , --HQ cannot hear anything  but branch is able to hear .  ( intermittently)

NOTE :

One strange thing noticed was when HOLD button is pressed & relased in the branch ip phone ,the call works TWO Way and both are able to hear.

HQ can make calls to branch and works perfectly...

Attached is the toplogy diagram...

Please revert ...

Regards,

[mopauly]

Has anything recently changed in the network topology?  Has this worked prior?  Have the routes been verified from the branch to the HQ office?  We recently had a similar issue.

[murthy2005]

Hi,

Thanks for the reply.

This is a new setup  & intermittent one way audio issues are there.

Say out of 5 calls from Branch to HQ  ,  3 Calls have this issue &  2 calls works normally .

The end to end  routes has been verified and are ok.

Regards,

[mopauly]

How is the MPLS routing configured? protocols?  Is QOS configured?

[murthy2005]

Hi,

  QOS is configured in the Branch Edge Router of MPLS  then it gets connected to the Telco-MPLS- CPE Router, which we dont have control on it.

The Sh policy map interface  in branch ,  doesnt show any packet drops or delays and everything looks normal...

Have checked the Firewall in HQ - Cisco ASA  , have enabled policy " IP ANY ANY  "on the Cisco ASA  , but still the issue continues...

regards,

[Bhunt 410]

Have you checked the routing to make sure the voice subnets are in the routing table.  Also the reason MOH maybe working is due to multicast instead of the VOIP IP.  The Voice will go across a certain IP range and Multicast MOH uses the multicast range.

[murthy2005]

hi ,

The voice subnets are able to ping each other , not sure why this is happening  intermittently .

Multicast is not enabled on MOH  .

Regards,

[mopauly]

When you mention intermittent, were these calls placed from the same phone at the branch office?

[murthy2005]

The calls were placed from different phone  in branch( cisco 7942)     to Cisco 7975 and 7942 Ph .ones in HQ

All calls have the same issue ..

Regards,

[murthy2005]

When i Call from branch  to HQ., may be the first time there will be a one way audio,

but when the second time the call goes through and everything is ok from the same ip phone .

[lcuevas1]

Please check the ASA logs and lookup for any deny UDP or Multicast packets coming from the CUCM or IP Phones over the test.

[murthy2005]

In the Cisco ASA in HQ  ,  i have enabled a IP Any Any  , to trouble shoot this issue ..

did not find a  packet drops in ASA .  Anything else to be checked from the ASA , apart from normal policies ?

regards

[gagarinjs]

Hi,

Where you able to isolate the issue and resolve it ?

I am facing a similar issue with one of a user, Who has a home office setup (IP Phone, Cisco 871 router), which passes over the internet to the Data Center and then over the MPLS network to the remote office.

Much appreciated if anyone could help.

Regards,

Gagarin

[Cristian Iconaru]

Hi,

we have exactly the same issue. have you managed to solve it?

Thanks.

Best regards

Cristian