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New Member

G.711 Signaling Bandwidth consuption!

Would anyone know how much b/w is consumed by G.711 signaling?

I know that G.729 signaling uses 0.5kbps od bandwidth, but I can not seem to figure out thet for G.711.

Any ideas?


Cisco Employee

Re: G.711 Signaling Bandwidth consuption!

Not sure if this is what you are asking. g.711 is 64k a sec. With no header compression the header is 16k so that would give you 80k a call. If you use header compression you should be able to get it down to 66-68k.

Hope this helps,


New Member

Re: G.711 Signaling Bandwidth consuption!

Thanks for the reply, but that's not what I need. I know the b/w consumption of G.711. What I'm concerned about is the signaling control protocol b/w consumption. I need to set up LLQ and reseve the b/w for 30 voice channels, so I need to know what b/w to reserve for signaling.

New Member

Re: G.711 Signaling Bandwidth consuption!

Dear asapun,

Need some clarification on the question - G.711 and G.729 do not include any signaling as such, and the 0.5 kbps does not ring a bell. You should only need to reserve BW for the bearer packets, which would in any case be RTP - the RTP packets will carry the G.711 samples or G.729 frames. Are your referring to the overhead added by RTP? For this some other factors come into play, such as packetisation period, which determines how often the packets are sent, which will determine the overhead for the RTP headers. RTP is UDP-based and the uncompressed RTP header is typically 12 octets in length (could vary, usually does not). You may also be dealing with RTCP as well, which is sent on the next higher port number than the RTP stream, for a given stream. RTCP bandwidth requirements for non-multicast sessions are very very low (1 packet about every 10 seconds, implementation-dependent period). Hope this helps.

New Member

Re: G.711 Signaling Bandwidth consuption!

What I mean by signaling, is skinny signaling b/w consumption as well as keep alives btw CM and IP phones.

When LLQ is implemented I reserve b/w for RTP and skinny as well:

policy-map VoIP

class VoIP-RTP

priority 1440

class skinny

bandwidth 30

The bandwidths are based on 60 simultaneous G.729 calls (RTP: 60 x 24 kbps = 1440 kbps and Signaling: 60 x 0.5 kbps = 30 kbps).

New Member

Re: G.711 Signaling Bandwidth consuption!

Typically I use 8k per 100 phones as a base for call setup bandwidth.

Hope that helps,


New Member

Re: G.711 Signaling Bandwidth consuption!

I have some question with regards to Pri-Qsig and the way Process indicators work can anyone help

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