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

[Leetun, Rob]

Quick question for you Eric on a different subject.  How do you make a
phone to not reboot all the time?  We get blocks of phones that reboot
all the time.  Thanks for your opinion.

Rob 

-----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 1:11 PM
To: dh8 at pobox.com; cisco-voip at puck.nether.net
Subject: RE: [cisco-voip] 7.1(2) voice quality issues, IP phone to IP
phone

I'm just getting involved in this issue, but they and others have been
focusing on the ATM side and carrier for past 6 months. It is vbr-nrt
right now but discussion of moving to -rt. I'm trying to rule out any
issues on the whole network end-to-end and any potential phoneload/CCM
issues since it is IP phone to IP phone and occurs now and then on the
same LAN locally. 

I don't believe SAA probes have been setup. 
I added QRT softkey yesterday when I got involved and awaiting results.
Will have a few monday to look at.

Theres no encryption set up on phones, or on the network, and since it's
IP phone to IP phone in same CCM cluster that would be CAC/location
setting. The phones aren't rebooting, etc so signalling and keepalives
are good and not getting lost. They also do have external call quality
issues for calls coming across same WAN to a PRI but I'm focusing on the
Internal call issues for now, because the issues causing that are going
to magnify issues on external calls.

Locations is set to 200k, and the router llq policy has 256k for
priority. No drops there. It's set for match-any ip rtp clause and dscp
ef (was before I got involved). I'm still investigating the end-to-end
QoS settings amongst all devices the calls travel through to make sure
nothing is resetting dscp/etc. 

I've done some 1000 packet size ping tests between the CCM server and
PCs at the remote site and its 40-45ms response time. I know not a good
test, but just getting an idea.

--- "Dennis J. Hartmann" <dhartma5 at optonline.net>
wrote:

> 	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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> 
> 



		
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