[OpenSIPS-Users] codec manipulation feature

[Raúl Alexis Betancor Santana]

On Tuesday 16 June 2009 12:48:20 Jeff Pyle wrote:
> Exactly.  This would be so incredibly useful.
>
> Imagine a customer with a SIP-based PRI and a T1¹s worth of bandwidth
> behind it.  This is a common scenario for my customers.  We try to avoid
> running all G.729 wherever possible because of the obvious and ugly audio
> quality hit.  At G.711 I can only let them use 17 channels on their 23
> channel PRI. That¹s fine for many customers but a fraction think they need
> or actually need all 23 channels.  Some can afford second T1 to allow them
> access to the remaining 6 channels.  How about <drum roll please> dynamic
> codec selection by the proxy.
>
> We¹ve already worked out the math and routing logic in Opensips, provided
> we have the following items in the customer¹s profile:
> * Total bandwidth available to customer (pick a circuit type, or input raw
> kbps)
> * Minimum percentage bandwidth reserved for data
> * Total number of calls required
>
> Given this information, Opensips can compute how many calls we can leave at
> G.711 and after what point we have to start compressing them into G.729 (by
> verifying G.729 in the SDP, and removing G.711).  Thank you dialog module.
> For example, on a 1.5 meg T1 with 15% reserved for data, the formula says I
> can allow 12 channels at G.711, but have to compress the remaining 11. 
> With a 5% data margin I can get away with 15 uncompressed and 8 compressed.
> Everything¹s just about ready except for the ability to work on the SDP to
> make it happen.
>
>
> - Jeff

Just as a comment ... if you have very bad quality with G.729, maybe your 
problem is on other place.

Having T1 line's for data, just for putting VoIP traffic ast SIP+G.711 is a 
waste of bandwidth, but that just my opinion.

Our customers uses ADSL lines ranging from 3Mb/320Kb to 10Mb/1Mb, and using 
the same line for Inet navitation + VoIP, over a 3M/320Kb line you could 
drive 5 G729 calls without any problem, and over a 10Mb/1Mb line, more than 
12 ... so I don't undestand where you have problems with a 1.5Mb/1.5Mb line.

-- 
Raúl Alexis Betancor Santana
Dimensión Virtual