[h323plus] Dynamic Bandwidth Management!!

Paul E. Jones paulej at packetizer.com
Mon Jan 21 08:59:33 EST 2008


Ah, OK.  That makes sense.

>From an H.323 perspective, this kind of thing is almost doable, but no remote device would be obliged to make adjustments.  One could send a Request Mode message and the receiver could politely refuse.  (Likewise, a SIP device could refuse an offer to propose changes to established media flows.)  The other issue is knowing whether or not bandwidth needs to be adjusted or can be adjusted.  One might say that bandwidth could increase, because there is no observed packet loss.  But, perhaps an increase in bandwidth might then disrupt some other service (e.g., other voice calls in progress).  So, then perhaps the bandwidth might be decreased to compensate.  This then leads one in a vicious cycle of bandwidth adjustments up and down.

And, as you rightfully point out, available bandwidth is constantly rising and it will continue, since people want to utilize services that require more bandwidth and want to use even more services simultaneously.  The 80Kbps voice call is really very little compared to the Gbps of bandwidth most broadband customers have today.  Still, there are bandwidth-constrained locations, but the best recommendation I could make is to simply select a lower bit-rate codec and use that.  Skype, for example, always uses G.729 for calls to PSTN gateways and the sound quality seems very good to me.

  ----- Original Message ----- 
  From: Frank Fischer 
  To: h323plus at lists.packetizer.com 
  Sent: Monday, January 21, 2008 8:42 AM
  Subject: Re: [h323plus] Dynamic Bandwidth Management!!


  i think he means the abillity to dynamically change the codec during transmission to follow any changes in available bandwith. I.e. when starting with g.711 and the available bandwith drops to 80kbits then i.e. g.729  could be negotiated on the fly. 

  Actually a very nice feature but probably not very easy to implement and more important, getting less and lesser important since bandwiths are constently increasing almost all over the world....


    From: h323plus-bounces at lists.packetizer.com [mailto:h323plus-bounces at lists.packetizer.com] On Behalf Of Paul E. Jones
    Sent: Monday, January 21, 2008 2:33 PM
    To: Abhishek Rohilla; h323plus at lists.packetizer.com
    Subject: Re: [h323plus] Dynamic Bandwidth Management!!


    H.323 Plus aside, what do you mean by "dynamic bandwidth management"?


      ----- Original Message ----- 
      From: Abhishek Rohilla 
      To: h323plus at lists.packetizer.com 
      Sent: Monday, January 21, 2008 4:44 AM
      Subject: [h323plus] Dynamic Bandwidth Management!!


      Someone please help me with this.
      I wanted to know does H323+ does dynamic bandwidth management and mange the codec bit rate accordingly?

      How is it  done.?? Where can I find the code in RTP files in H323+ where bandwidth info is calculated? 


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