[cisco-voip] deploying qos on my edge router

[Ted Nugent]

I provided an example last night that would be ideal
based on Cisco recommendations (pasted below). However
there are other considerations that you need to think
about as well if you don’t have the luxury of
designing the link for a site.

If the circuit is already in place then the question
should not be, how many calls traverse the link. It
should be how many calls should I allow to traverse
the link. In a perfect world you configure your QOS
based off of X number of calls and use CAC/AAR to
prevent additional calls. If you engineer your link
for X number of calls then you've drawn a line in the
sand and said this in the only number of calls that I
will allow over the link. If you don’t take this
approach then call X+1 will not only be subject to
voice quality issue but the quality for ALL calls on
the link are now subject to degradation (aka LLQ only
protects X calls). 
So if you can’t engineer the link to suite your need
then you need to engineer QOS to suite your link.
Cisco typically recommends using about 33% of the link
speed for real time traffic and around 5% for control.
This is not set in stone it’s simply a recommendation.
I’ve seen circuits with 50%+ carved out for voice
traffic with no noticeable voice quality issues. And
as I stated the best LLQ configuration in the world
will not help you if you over subscribe the number of
calls on the link. Your best bet is to configure a
safe LLQ policy and use it in conjunction with CAC
(location or GK) and AAR. If you have more detailed
info on what you’re trying accomplish (link speed,
link type, amount of data on the circuit etc) then we
might be better armed to help you out. Thanks

HTHs
Ted
======================
My response from last night

A good place to start is the QOS SRND

http://www.cisco.com/univercd/cc/td/doc/solution/esm/qossrnd.pdf

Check out the WAN Aggregator section for
Classification/Marking and on Link type/speeds.

Here's a very simple LLQ config and remember if you're
using FR you need to shape so that you don't burst
over your CIR. There are some good examples of this in
the SRND.

class-map match-any control
 match protocol skinny
 Match protocol mgcp
class-map match-all rtp
 Match protocol rtp
!
!
policy-map LLQ
 class rtp
  priority percent 33
 class control
  bandwidth percent 5
 class class-default
  fair-queue
!

HTH Ted




--- James Grace <jgrace at digitel.net> wrote:

>  
> 
> What would be the best way to apply MQC  on our edge
> routers  for voice.  If
> I want to priorities the traffic and allocate the
> bandwith.  But I have no
> ideal how much bandwith to allocate for voice.  Most
> of our voice traffic
> will be from incoming calls with no answer and them
> going over the wan to
> geto unity VM.  Unity is set for g729  and my remote
> site are set to 729 for
> site to site and 711 for local 
> 
> Using MQC
> 
>  
> 
>  
> 
> James D. Grace 
> 
> CCNP CCNA MCSE MCSA 
> 
> Digitel Corporation
> 
> System Engineer / Professional Svc.
> 
> MSN messenger ID:  jgrace29 at hotmail.com
> 
> Mac IChat ID:  jgrace29 at mac.com
> 
>  
> 
>  
> 
> > _______________________________________________
> cisco-voip mailing list
> cisco-voip at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-voip
> 


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