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New Member

VoIP Bandwidth Issue

I had a user today report that she had two users on he line and when she attempted to transfer the calls she received the following error "not enough bandwidth" She was trying to transfer the call within her location not across the WAN.

She is located in a remote branch with a DS-1 and a Cisco 2811 router. I could see where CCM would not transfer the call if all the bandwidth is being used on the WAN but not on the local segment. Am I missing something here? Thanks!

New Member

Re: VoIP Bandwidth Issue

There would seem to be a location setting missing from one or more devices at this remote site. Check the location setting on the PSTN connection, the phone the user was transferring to, any CTI route points that may have been used, hunt pilots, etc.

If you can reproduce the error, try resyncing the bandwidth on the remote location as well.

New Member

Re: VoIP Bandwidth Issue

I experienced the same problem except my user was dialing an extension within the same location. Call Admission Control is not used when dialing to and from the same location. CAC is only used if the call crosses the WAN.


Calls between devices at the same location do not need call admission control because those devices reside on the same LAN, which has unlimited available bandwidth. However, calls between devices at different locations must travel over an IP WAN link, which has limited available bandwidth.


Does anyone have any thoughts?


Re: VoIP Bandwidth Issue


One reason the message may have been displayed is the transfer process. If you are not providing MOH from the local router the RTP stream will be sent from the MOH server when the transfer process is invoked by the user. MOH is g.711 by default and may have put the bandwidth in use over the limit for the site.

The RTP stream is interrupted when transfer or hold is used, and the stream is rerouted to the MOH provider until the call is resumed.

As Jeff stated, the locations portion of CCM (System -> Locations) is where the bandwidth allocation is set for the cluster. If you are using a g.711 codec across the WAN you can also change to g.729 if the call volume is high and cost for another DS1 facility to the site is an issue. The codec is managed in CCM admin under System -> Region.

Hope that helps.


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