Constant noise in background in voip network

[mohammed asif suleman]

Hi,

we have 3 branches and 20 small home offices setup.

we installed CUCM 8.6 running and serving all the branches and home offices.

All branch voip network is good, but we hear background noise while calling home office ip phones, the background noise is heard at headoffice only, at home office side it is good.

i couldn't figure out where it is going wrong.

the setup is like

IP Phone------> call manager------> gateway(cisco 1940)------->internet----------> homeoffice router(cisco881)--------->ip phone.

the home offices are connected over DMVPN tunnels. and the bandwidth is 1 MB for the tunnels.

attaching router config for head office gateway and home office router

[Abhijit Bhowmick]

HI Mohammed,

Can you please let know what kinf od sound are you hearing. Is it a crackling sound or a hissing sound. What type of IP phones are used at both locations and the firmware used.

Regards,

Abhijit

[mohammed asif suleman]

Hi Abhijit,

thank you for the reply,

its some kind of crakling sound.

we are using 6921 at home office side and 8941 and 6921 at headoffice side, but i found no issue with phones,these are working fine in internal network, when i did .mute the phone at home office side, there is no sound on head office side..

is there any problem with the encryption used on tunnel, i applied qos for the voip but found no difference..

please can you help me...

[Abhijit Bhowmick]

Is your packetization greater than 80 bytes on the router. If yes try setting codec packetization to 80 bytes on dial-peer or voice-class  codec.

[mohammed asif suleman]

Hi,

It is not a voice gateway, there are no dial-peers on this gateway, its just a vpn router , gateway for home offices..