[Asterisk-Users] Asterisk and Cisco 7960 problems persist (for me, anyway)

[brian]

Just an FYI if you can run tethereal -n udp port 4569

And watch the timestamps(should be even 20ms increments per call leg).  Both
ends will need to be updated also.  If not you will get some very strange
timestamp issues and jitter and timestamps "might" not be right.  If you
have one end on cvs-stable and one on cvs-head you might see this problem
also.  I don't see any issues with IAX2 from my 7960 out nufone.

bkw

> -----Original Message-----
> From: asterisk-users-admin at lists.digium.com [mailto:asterisk-users-
> admin at lists.digium.com] On Behalf Of Rich Adamson
> Sent: Friday, May 07, 2004 11:36 AM
> To: asterisk-users at lists.digium.com
> Subject: Re: [Asterisk-Users] Asterisk and Cisco 7960 problems persist
> (for me, anyway)
>
> > It seems that each time I get a new checkout of * from CVS my Cisco 7960
> > works worse than before. I know this stuff's in flux, so I mention this
> > in case it's news.  Anyone else having trouble?  What I'm seeing (er,
> > hearing) is really choppy audio. The previous version I had installed
> > had fairly frequent audio dropouts (not present when I make the same
> > calls through the same * box using a TDM400P interface).
>
> Brian,
>
> Are you having the choppy audio only on iax2 links or on other calls as
> well?
>
> There was an issue with erratic iax2 timestamps which caused the Cisco
> phones to effectively drop any sip packet that had uneven timestamps
> causing extremely choppy audio. The choppy audio (as I seen it) was
> only in one direction (from the iax2 source with the erratic timestamps
> towards to 7960 phone).
>
> If your issue is not associated with iax2, then be aware the Cisco v6.x
> code changed DSP firmware internally, and any sip/rtp packets arriving
> with
> uneven timestamps (within the rtp pkts) will be dropped and cause the
> choppy audio. You should be able to see the timestamps with ethereal.
> The timestamp difference between successive pkts should be exactly
> 160 milliseconds; if its anything else, the phone will drop the pkt.
> (Not sure if that is a real Cisco bug or a planned change, but it
> certainly has a hugh negative impact on voice quality.)
>
> I'm running CVS-HEAD-05/02/04 with no problems today.
>
> Rich
>
>
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