[cisco-voip] 7.1(2) voice quality issues, IP phone to IP phone

[Dennis J. Hartmann]

	What are the SAA (Service Assurance Agent) voice probes reporting
during this time?  I'm assuming that SAA probes are being sent in the first
place.  If they're not, this would be an easy way of completely ruling out
the network.  

	What are the call volumes during this time?  

	What CAC mechanism are you using?  Locations does not account for
IPSEC/SRTP and Layer 2 overhead.  H.323 CAC does not align with the priority
queues.  

	I think the most important parameter would be the delay incurred by
the ATM provider.  Even though your not receiving lost packets, you may want
to take a look at the jitter on the phone during this time.  Enable the QRT
(Quality Reporting Tool) and train the users to click this soft key during
bad calls so you have something to go from.

	Also, enable CMR (call management records) that will tag your CDRs
with QoS information so you can see what's going on in the network side.

	Service providers have a very bad habit of maxing out memory in the
TX and RX buffers so they delay ATM cells rather than drop them.  

Dennis Hartmann
CCVP/CCIP/CCNP/CCSI/MCSE

-----Original Message-----
From: cisco-voip-bounces at puck.nether.net
[mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Erick Bergquist
Sent: Saturday, October 01, 2005 1:40 AM
To: cisco-voip at puck.nether.net
Subject: [cisco-voip] 7.1(2) voice quality issues, IP phone to IP phone

Hi,

Just want to bounce this off list. Working on issue on a 4.1(2)sr1 system
with 7960s on 7.1(2) currently.
They have 3 remote sites, ATM between sites. QoS/LLQ is set and no drops but
users reporting issues with IP phone to IP Phone calls, where the call will
be fine for a few minutes then after a few minutes it starts to cut in and
out and progressively gets worse. The call doesn't drop. No WAN/LAN
interface errors along path calls travel. 

They have regions set, and are doing G729 between sites and have 200k
bandwidth allocated under locations/CAC. No out of resources (checked the
servers location performance counters). No drops on QoS policies and LAN
appears to be ok with no visible issues.

They are also experincing echo on IP to IP phone calls now and then between
sites, and between 2 IP Phones on same LAN in same device pool (G711 in this
case).

I am aware of bug CSCeh01099 which may be playing a factor here maybe, but
looking to see if anyone else has ran into this or not. I'm pushing for a
phoneload update to 7.2(2) or 7.2(3) to start with and have set up QRT
softkey on phone also. this bug id also mentions CCM version for fix so do
also have to upgrade CCM to 4.1(3)sr1 to get complete fix?


		
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