[cisco-voip] Delayed audio-cutover with H.323 gateway

[Erick Bergquist]

FYI,

Got this fixed up by adjusting QoS policies on routers.  The core issue was the DNs involved were shared across a number of phones and the amount of control/signalling traffic exceeded the 64 packet queue-size (default). Increasing the queue-limit of the control class fixed the problem. 

----- Original Message ----
From: Erick Bergquist <erickbe at yahoo.com>
To: Wes Sisk <wsisk at cisco.com>
Cc: ciscovoip <cisco-voip at puck.nether.net>
Sent: Tuesday, September 12, 2006 8:22:28 PM
Subject: Re: [cisco-voip] Delayed audio-cutover with H.323 gateway

Ok. I have a couple traces I am going through (CCM and debugs from router). 

The interesting part is the user is hearing a clicking sound when the delay happens (like someone is hanging up a phone) when the audio cuts in and becomes hearable. Sometimes it is very loud. Sometimes not as loud. 

When they transfer a call to another IP Phone, usually when the other person picks up the caller on PSTN side doesn't hear them for 4 to 8 seconds. Sometimes it works fine with no delay. I am leaning more toward a GW or network issue somewhere at this point. Calls on PRI's do not have this problem - just analog ports.

----- Original Message ----
From: Wes Sisk <wsisk at cisco.com>
To: Erick Bergquist <erickbe at yahoo.com>
Cc: ciscovoip <cisco-voip at puck.nether.net>
Sent: Tuesday, September 12, 2006 1:57:17 PM
Subject: Re: [cisco-voip] Delayed audio-cutover with H.323 gateway

Fast start should not apply here.  make sure you are not dropping 
packets or retransmitting due to network loss between the 2 but fast 
start should only be necessary when you're looking at 40msec+ RTT gw to 
CM.  You have problems either on the GW or on the CM with getting those 
channels opened fast enough.

off the wall idea - enable 'file close thread flag' to make sure you 
aren't hitting that issue.  then get CCM and SDL traces from an 
occurrence.  look in the traces to obeserve the time from user offhook 
to startmediatransmittion to phone and open receive channel ack from the 
phone.  If that is small, then it is a problem with audio cut through on 
the gw itself.

/Wes

Erick Bergquist wrote:
> 4 to 8ms on average. Fast start not enabled on GW - let me look into that.
> 
> ----- Original Message ----
> From: Wes Sisk <wsisk at cisco.com>
> To: Erick Bergquist <erickbe at yahoo.com>
> Cc: ciscovoip <cisco-voip at puck.nether.net>
> Sent: Tuesday, September 12, 2006 8:31:19 AM
> Subject: Re: [cisco-voip] Delayed audio-cutover with H.323 gateway
> 
> What is round trip time from gateway to CM?  Are you using fast start  
> on CM and the gateway?
> 
> /Wes
> 
> On Sep 11, 2006, at 10:19 PM, Erick Bergquist wrote:
> 
> Hi,
> 
> I'm having a issue where an inbound call comes in FXO port and  
> connection plar's to a shared DN across 5 IP Phones. The phone call  
> gets answered fine, but the user on IP phone saids "Welcome to  
> BlahBlah" and the outside caller doesn't hear the first time they say  
> "Welcome To BlahBlah" and the IP Phone user repeats their greeting  
> and they hear it the second time fine.
> 
> There are no errors on any interfaces that I can see, and the gateway  
> has voice rtp send-recv enabled. Issue does not happen on calls over  
> PRI, just the analog FXOs. I have disabled caller-id on the voice- 
> port and also tried connection plar opx with no difference. Sometimes  
> it works fine but rarely.
> 
> CCM is version 4.1(3)sr3c and the gateway is a 1760 running 12.4(8a).
> 
> A similar problem can happen when the call is parked or put on hold  
> also, now and then.
> 
> 
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> cisco-voip at puck.nether.net
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> 
> 




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