Plantronics + Polycom. Now together as Poly Logo

limitation on vbp bandwidth

Occasional Advisor

limitation on vbp bandwidth



i'm looking for a way to limit the bandwidth on our vbp 4555


In the VOIP ALG we have :


Maximum total bandwidth (kbps):0

Maximum per-call bandwidth (kbps):0

Default audio stream bandwidth (kbps):64

Default video stream bandwidth (kbps):1024


The bandwidth we have licensed is 3 Mbps


In practice this means if we have two clients communicating at 1472 kbps it's over.


So i believe i need to set the maximum bandwidths.  But then this will refuse connections if a requested bandwidth is higher then the maximum allowed?


There is no way to transcode a connection to a lower bandwidth?

Message 1 of 3
Valued Contributor

Re: limitation on vbp bandwidth

Once you will set maximum bandwidth so external party can connect VC call below or to that bandwidth only


Let say if you will set 768KBPS so no one can call beyond 768KBPS if they tried to inisiate call over 768KBPS they get packet losses at their end




Message 2 of 3
Polycom Employee

Re: limitation on vbp bandwidth

All correct, as the desgin of the feature(tte) in the VBP is just that: to prevent calls above the BW limit.


The VBP does not support transcoding bwA to bwB.


In order to support downspeeding, the VBP would need to be in the GK-RAS path in order to see BRQ messages, which is how it works in the Polycom environment. Although there are some setups where this does work, it is only in implmenetations where there is a full gatekeeper involved, and when calling and called parties are registered to that GK.


Your example is a B2B call, one autonomous system calilng another autonomous system, in which there is no GK-RAS messaging. The end result is no downspeeding support possible. With the 43xx series and 3MB, your only recourse is to set the limit as you stated.








Message 3 of 3