[cisco-voip] SIP phone jitter, how do I find the culprit?

[Jason Dance]

Thank you for the tips Roger.  I've found this article here which helps
me to decipher EF and LLQ:
http://www.cisco.com/en/US/tech/tk543/tk757/technologies_tech_note09186a
00800949f2.shtml
As I am rather green with QOS, it appears it is time for me to know more
so I can attempt to resolve this issue.

I will respond back with what I find for the benefit of the group.

Thanks again!
Jason

-----Original Message-----
From: Roger Wiklund [mailto:roger.wiklund at gmail.com] 
Sent: Sunday, February 26, 2012 2:49 PM
To: Jason Dance
Cc: cisco-voip at puck.nether.net
Subject: Re: [cisco-voip] SIP phone jitter, how do I find the culprit?

As SIP is only the signaling it's not super important what path it
takes, but it I would say yes to question 2.
RTP is what's important and I assume you use RTP flow-through in the
CUBE so your audio path should be:

Phone-----------------CUBE-----------------------ITSP

I would start by checking the routing/QoS from the phone to the CUBE.
That's most likely LAN so prob. no issues there.
Next step is to check CUBE----------------ITSP and I assume this is over
some sort of WAN, check routing/QoS there and ensure EF has the highest
prio with LLQ etc.

Look in your switches/routes for any drops in/problems in the EF queue
and see if you can find something strange.

/Roger
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