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New Member

simple qos config on cisco router for voice traffic

Hi all, can anyone give me a simple config for qos for my voice traffic, I need to prioritize the signalling for af21 and payload for ef46

please help

cheers

Carl

12 REPLIES

Re: simple qos config on cisco router for voice traffic

Super Bronze

Re: simple qos config on cisco router for voice traffic

(For many routers.)

class-map match-any payload

match dscp ef46

class-map match-any signalling

match dscp af21

policy-map simple

class payload

priority . . .

class signalling

bandwidth . . .

interface ?

service-policy output simple

New Member

Re: simple qos config on cisco router for voice traffic

can you tell me what config you would out in these ?

class payload

priority . . .

class signalling

bandwidth . . .

?

Super Bronze

Re: simple qos config on cisco router for voice traffic

Unsure what you're asking. If you're wondering about the " . . . ", that's where you specify the bandwidth allocations. Syntax depends on IOS version and how you desire to specify bandwidth; value depends on what your VoIP traffic needs.

New Member

Re: simple qos config on cisco router for voice traffic

hi

thanks for the reply

so, would this be the minimum bandwidth allowed ,what would you normally put for this?

Re: simple qos config on cisco router for voice traffic

Carl,

That would highly depend on your VoIP requirements.

1) VoIP Codec

2) Number of Calls

3) Concurrent Calls

4) Call Signaling

5) VoIP Keepalives

If you do not know the above - you need to, otherwise your VoIP and QoS will not meet your requirements.

New Member

Re: simple qos config on cisco router for voice traffic

ok,

voip codec, g729

max calls say 20

concurrent 10

call signalling h323

dont know about voip keepalives

Re: simple qos config on cisco router for voice traffic

OK - so:-

(G729 Codec)x(# of concurrent calls) = Bandwidth required for LLQ

Super Bronze

Re: simple qos config on cisco router for voice traffic

According to the following, http://www.cisco.com/en/US/products/ps10030/products_qanda_item09186a0080a36a8e.shtml#qa3, G729 uses 24 Kbps per call.

Somewhere on Cisco's site, I recall there's better documentation for bandwidth requirements, but unable to find it at the moment. Hopefully such documentation would also provide bandwidth needed for signalling, although generall that's not too much (10% to 20% of the bearer bandwidth?)

New Member

Re: simple qos config on cisco router for voice traffic

what kind of qos would this be called, just priotising, or is it policing ?

Super Bronze

Re: simple qos config on cisco router for voice traffic

For the voice bearer traffic, both. (The sample config I provide uses CBWFQ and places the voice bearer traffic into LLQ, which sends its traffic first, but also polices the maximum bandwidth when there's congestion.)

For the signally traffic, bandwidth reservation. (Normal CBWFQ classes, should guarantee a minimum defined bandwith when there's congestion, although more might be used.)

Re: simple qos config on cisco router for voice traffic

This is what you were refering to:-

http://tools.cisco.com/Support/VBC/do/CodecCalc1.do

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