IP Telephony - NBX
cancel
Showing results for 
Search instead for 
Did you mean: 

NBX- bandwith. VTL vs SIP

DanCarroll
Frequent Advisor

NBX- bandwith. VTL vs SIP

Is there a bandwith usage difference between VTL and SIP calls?
9 REPLIES
merlin_1
Super Advisor

Re: NBX- bandwith. VTL vs SIP

No not at all . You can set the codecs to the particular bandwidth for the calls thru the NBX .

This message was edited by merlin on 10-29-09 @ 9:07 AM
DanCarroll
Frequent Advisor

Re: NBX- bandwith. VTL vs SIP

Is there much loss of quality  going to G729 for SIP calls?



What are the benifits of G711 vs G729



merlin_1
Super Advisor

Re: NBX- bandwith. VTL vs SIP

Quality is not an issue . Compression is . G729 uses more compression and less bandwidth . Should only be used if you measure your network traffic and find that bandwidth between sites ( size of the packets and amount of traffic )



This is a basic description but if you go out and review the codecs you will find some audio differences as well due to the compression .



a whole topic for discussion . Our docs state some clear info in re to codecs as well .



bosoxfan_1
Super Advisor

Re: NBX- bandwith. VTL vs SIP

Hi.



If you are asking about audio quality between g.711 and g.729, we all know that g.711 has better audio.. However, I am betting that if you put two phones side by side and made 1 call with g.711 and another with g.729, 1 out of 10 people could pick out which is which.. presuming no network bandwidth issues, etc... I know I have spoken to people and they could not tell the difference.



 



DanCarroll
Frequent Advisor

Re: NBX- bandwith. VTL vs SIP

I have to verify that the pcxsets i am running are using G729 as I had set under Bandwidth custom settings.



How would I determine that the calls are actually using G729. This is on a NON sip NBX.



 



bosoxfan_1
Super Advisor

Re: NBX- bandwith. VTL vs SIP

The best way is to take a network trace... then look at the size of the audio packets. g.729 is around 66 bytes (this is layer 2 frame,including headers), g.711 is around 228 bytes.



DanCarroll
Frequent Advisor

Re: NBX- bandwith. VTL vs SIP

what ports are used for audio that I can see on wire shark for non sip units?



DanCarroll
Frequent Advisor

Re: NBX- bandwith. VTL vs SIP

  I have the entire system now set for G729 compression.



When I call another phone. my pcxset is sending packets at 214 bytes data and a 14 byte header.



same conversation  -- my pxset is recieving  packets at 52 bytes data and 14 byte header.



Thesse are on the same system and network. Level 2 at this time.



Why is there a difference????



bosoxfan_1
Super Advisor

Re: NBX- bandwith. VTL vs SIP

for non-Sip mode, it is ports 2093-2096. I believe port 2094 is for the audio.