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New Member

CIPC Latency Problems

Hello all,

We are testing out the IP Communicator for deployment to our outside sales staff. During our testing, we've found that some people can VPN (Microsoft PPTP VPN) into corporate from their homes and their CIPC works perfectly. However, for others, as soon as they place a call through the soft phone, their ping times go from <50ms to upwards of 1000ms. Obviously, this causes all sorts of delay. As soon as you disconnect the call, the ping times return back to normal. If we remove their router (Linksys WRT55AG, being one of them) from the config, it works perfectly.

I've tried turning off the SPI firewall within the router, as well as flashing it to the newest firmware. Nothing has helped.

Has anyone experienced this before?




Re: CIPC Latency Problems

To test which latency setting is best for your particular set of audio devices (USB headsets, USB handsets, and/or sound cards), use the following procedure to modify Cisco IP Communicator's audio parameters.

Step 1 In the Cisco IP Communicator program folder, double-click on one of the

following .reg files:

"LowDelay.reg (Lowest latency, default setting)



"VeryHighDelay.reg (Highest Latency)

Step 2 When prompted, confirm that you wish to import the settings into your Microsoft Windows registry.

Step 3 Make a test phone call and verify that the audio sounds good to you and to the other party. If you hear distortion, audio dropouts, or robotic sound, proceed to the next file on the list and repeat the previous steps.



In general, it is recommended that you test the .reg file with the lowest settings first and continue to the next .reg file, if needed.

New Member

Re: CIPC Latency Problems

Thanks for the suggestion. Unfortunately, I don't have any .reg files in my CIPC program folder so I was not able to test this.

It seems as if there is a problem with the traffic going through the wireless router devices at the end user's homes. Some of the users have no problems, others have all sorts of trouble.

Here is a scenario that fails:

Dell Core2Duo laptop


Linksys WRT55AG wireless router

Cable Internet Connection

Microsoft PPTP VPN to Corporate

Once she's VPN'd in, she loads up CIPC. See below for what her ping replies do.

The first section is while the CIPC is idle, the second part is when she connects a call to corporate (or even calls voicemail). As soon as the call disconnects, the ping times return down to the 30-40ms range. If we remove the Linksys router and plug the laptop directly into the cable modem, there are no problems. Why would the (Cisco) router cause a problem? Any further help would be greatly appreciated.

Reply from bytes=32 time=28ms TTL=127

Reply from bytes=32 time=30ms TTL=127

Reply from bytes=32 time=38ms TTL=127

Reply from bytes=32 time=31ms TTL=127

Reply from bytes=32 time=31ms TTL=127

Reply from bytes=32 time=31ms TTL=127

Reply from bytes=32 time=35ms TTL=127

Reply from bytes=32 time=39ms TTL=127

Request timed out.

Reply from bytes=32 time=810ms TTL=127

Reply from bytes=32 time=567ms TTL=127

Reply from bytes=32 time=359ms TTL=127

Reply from bytes=32 time=140ms TTL=127

Reply from bytes=32 time=390ms TTL=127

Reply from bytes=32 time=175ms TTL=127

Reply from bytes=32 time=3740ms TTL=127