[cisco-voip] QoS in distributed cluster

[Philip Walenta]

I would highly recommend reading the CallManager 4.0/4.1 SRND here:
 
http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_implementation
_design_guide_book09186a008044714e.html
 
and the QoS SRND here:
 
http://www.cisco.com/univercd/cc/td/doc/solution/esm/qossrnd.pdf
 
They go over many of the questions you ask.
 
The base configuration for CallManager recommends 900k between CallManager
pub and sub per 10,000 bhca.
 
The one thing that concerns me about your setup listed below is that it is
all L2.  One spanning tree problem (or even simple reconvergence) could
seriously mess up your voice network.  I'd consider some readdressing and a
move to L3 between your "WAN" links to help prevent problems, and you
definitely have the hardware to handle this.
 
I don't recommend using policing for any voice traffic (particularly
CallManager).  Marking voice and CallManager traffic according to the SRND
has been enough for me in the past.  In your case with an all-switch
network, the recommended queue depths on the 100MB links should be
sufficient (assuming latency is currently good) .


  _____  

From: cisco-voip-bounces at puck.nether.net
[mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Ruben Montes
Sent: Tuesday, December 13, 2005 5:33 AM
To: cisco-voip at puck.nether.net
Subject: [cisco-voip] QoS in distributed cluster



Hello,

 

I have a distributed cluster. The publisher is located in one city and the
subscriber is in another one. The network is a LAN-to-LAN with all L2
interfaces.

In the best case, there are two 100MB hops between the CallManagers, and in
the worst case (redundant path) two 10MB hops. I'm a little bit worried
about that and I would like to configure QoS. We have a bunch of devices
between the CCMs:

-         C6500 with sup720

-         C4500 with 4232L3

-         C3548

-         C4506

 

My question is if it enough to mark the interesting traffic and map it to a
high priority egress queue in all the path, or if it is necessary to
agreggate policiers to limit the traffc.

 

If I had a WAN I would configure CWFQ, but in this case, which do you think
is the best option?

 

Regards,

 

Ruben

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