Required Bandwidth for VOIP phones

[kam72]

Hi everybody

I recently established VPN tunnel between two countries.
Location 1 and Location 2 has got cisco IP phones.

When i use IP phones across wan the internet is disconnecting. I cannot speak more than two minutes, After two minutes my internet is disconecting and then i have to reboot my PIX firewall to get internet up and running.

When i use IP phones locally its not disconnecting. Can anyone tell me whats the actual reason.

My current ADSl plan is 512/128. Shall i upgrade the plan if yes how much will be the required bandwidth.

Thanks

 

[lui3]

do a simultaneous ping across the wan/vpn while on the phones. packet loss maybe your problem. are the phones losing association with the call manager when this happens.

Lui3
CCNP,CCDA,A+/Net+
Cisco Wireless Specialization

 

[pndscm]

If you have the phones set up for G729 codec, CallManager requires 24kb per call PLUS VPN header. If you are using G711, CCM requires 80kb per call PLUS VPN headers. The header size depends on the type of VPN tunnel and if you're using encryption. VPN headers can double the BW requirements.
If your WAN doesn't disconnect without an IP call, make sure your QoS settings are allowing enough bandwidth to send keepalives to the DSL provider. You only want to reserve a maximum of 75% of your available BW. The other 25% is for router to router 'housekeeping' traffic. At 128kb, you'll only be able to make 1 G729 phone call at a time maximum and have maybe 25kb left for data.

 

[kam72]

Thanks my problem is solved. What basically i did i followed the instruction which is provided by you.

I have created the two device pool Location A and Location B
and changed the codec from G 729 to G711 vice versa on both location.

Hence my problem is solved i am very happy.

Thanks for the support
Have a good weekend.