North American Network Operators Group

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Re: estimating VoIP data traffic size from VoIP signaling traffic size ?

  • From: Blaine Christian
  • Date: Sun Oct 23 21:29:03 2005

Use about 100k per call for 711u and it will help make the numbers

    actually around 88.2k.

I did say round you know! Lol... Things like VAD would drop the numbers even lower for G.711.

nice and round.

If you are trying to calculate busy hour search for
Erlang on your nearest web confabulator. There are also innumerable
spots on the web where you can find typical numbers for various codecs.

    I'd like to suggest to people looking at these things to
insure that your stats toolset includes both bps and pps in the
polls.  SYNs are low bps rate, but a high pps rate of them can mean
something bad.. it's useful to know how fast these counters are
Agree with you on that one... PPS is commonly overlooked. Folks are so interested in those bits per second they sometimes miss the obvious. From the VoIP perspective it would also be helpful to keep track of your signaling to RTP traffic ratio. If you find that your signaling demands have increased dramatically compared to your RTP traffic you may have "other" problems to worry about besides maintaining link capacity. If you find that your RTP traffic has suddenly increased it is certainly a potential worry factor as well.

I just finished dealing with a mysterious sudden growth in RTP traffic. The bad part was that it caused initial happiness (the money dance) followed by "oh crap we have a bug" a couple days later. Incomplete signaling can bite you pretty hard when DSPs don't know they are supposed to hang up.