[cisco-voip] Voice Delay

[Walenta, Phil]

Do you have this problem with any of your local-to-the-CallManager
gateways?  If not, you could be running into latency issues, or possibly
older software on your gateways.  This sounds like one of several
audio-cut through delay issues that used to exist.
 
A few tests - 
 
1.  Make a call from an IP Phone at your CallManager site to the phone
at the remote site - see if the call gets established and shows as
connected quickly.  If things work here like they should, your
signalling path should be ok.
 
2.  Make a call from the outside to that same phone, and watch the
amount of time from when you go offhook, to when the phone shows a
connected state.  If no delay is present, you may have an audio
cut-through issue.  If a delay is present, something may be interfering
with control traffic to the gateway, or quite possibly the VPN/IPSEC
encryption process is causing the delay.  
 
3.  Kick the router into SRST mode and see if the same problem exists
(in other words, prevent any control traffic from crossing the WAN).  If
it does, it may be an issue with the FXO cards, or the phone lines
themselves.

 
________________________________

From: cisco-voip-bounces at puck.nether.net
[mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Blomfield, Adam
Sent: Monday, November 15, 2004 10:28 AM
To: cisco-voip at puck.nether.net
Subject: [cisco-voip] Voice Delay



I have several remote sales offices that are connected to our
CallManager cluster over internet VPN connections. Most of the time they
work fine; other than the occasional voice breakup that is to be
expected when running over a public network. One problem that seems to
come up is a delay in establishing the voice path. This happens at one
office on a very regular basis. The phone will ring and the user will
pick up the receiver, however it takes about 10 - 15 seconds for the
voice path to be established. They find themselves repeating "hello...
hello?" into the handset about three or four times before the other
person can hear them. The seems to be happening most frequently on
external calls. The sites all have local PSTN connections coming into
FXO ports on a local 2600 series gateway. This is used for both incoming
and outgoing calls. I don't see how where the latency is occurring as
the voice traffic never actually traverses the WAN. The call control
packets are obviously happening as the phone rings, and after that
everything should be local so there should be no delay. Does anyone have
any ideas?


Thanks,
Adam

_________________________________________

Adam Blomfield
WAN Administrator
Information Technology
Sulzer Chemtech USA, Inc.
E-Mail mailto:adam.blomfield at sulzer.com
<mailto:adam.blomfield at sulzer.com> 
Internet http://www.sulzerchemtech.com <http://www.sulzerchemtech.com/> 
_________________________________________

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://puck.nether.net/pipermail/cisco-voip/attachments/20041115/d97713bc/attachment-0001.html