Jitter on IP Phone

[ciscovoipsupport]

Hi All,

Need your suggestion..

Topology: IP Phone = SCCP = CUCM = SIP = CUBE = Provider

Issue:- Customer phones are connected to server using VSAT links.. Which causes Jitter value to Spike on phone (Value you get after pressing ??).. How can i find the cause for this random Jitter... what configuration can i check?

[Terry Cheema]

VSAT is probably the cause. What sort of latency do you get from the sat links?

You can probably check the qos to make sure your traffic is getting marked correctly and prioritized, this is the only option I think possible to clear some jitter but nothing much you can do here if the links are bad, user experience will deteriorate.

-Terry

Please rate all helpful posts.

[Aaron Harrison]

Hi

You might also be able to set up an alternate codec such as iLBC which may perform better with your sub-optimal network conditions.

Aaron

[ciscovoipsupport]

Packets are Prioritized.. I have capture personally checked for DSCP marking..

Couple of Questions i have:-

1. When i check CDR i can see Jitter as 10 or less on Originating device.. and Null as Detination device.. But on the phone it showed 100+ why am i seeing this variation between CUCM and IP Phone?

2. Packatization is 40 ms as per station D message Start media transmission message... is there a possibility for phone to change this to 20ms?

[Simon Coventry]

Any update on this issue gents? I have almost exactly the same scenario described here.