Re: [AVT] Uncertain about timestamp usage in RFC 2833 named events

["Rex Coldren" <coldrenr@agcs.com>]

The first interpretation is correct.

Rex

"Wong, David" wrote:

> Steve, I had this same question a while back and I think the consensus is
> your first interpretation, with the timestamp corresponding to the beginning
> of the event and the duration incrementing until the event finishes.
>
> Also, with regards to the Cisco phone, I had a couple of SIP phones that I
> sniffed a while back, booting with a fairly old IOS, and I saw the behavior
> you saw--the timestamp was incrementing while the duration was constant.
> However, when I upgraded the IOS for both phones to the most recent one
> available on the Cisco site, I saw the correct behavior--same timestamp, but
> cumulative duration.
>
> David Wong
> Software Engineer
> Communications Infrastructure Test Group
>
> p| 978.661.1241 f| 978.988.0148
> email | dwong@empirix.com
> 205 Lowell Street | Wilmington, MA | 01887
>
> E M P I R I X
> http://www.empirix.com
>
>   > -----Original Message-----
>   > From: Steve Lubbs [mailto:s.lubbs@ieee.org]
>   > Sent: Thursday, October 03, 2002 12:54 PM
>   > To: avt@ietf.org
>   > Subject: [AVT] Uncertain about timestamp usage in RFC 2833
>   > named events
>   >
>   >
>   > Hi Folks,
>   > I am in a bit of a quandry related to how the timestamp for
>   > RFC 2833 named
>   > events should be implemented. My interpretation of the RFC
>   > is that the
>   > timestamp marks the start of the event and that this same
>   > timestamp value is
>   > used in all subsequent packets associated with the event.
>   > Further, the
>   > duration value is cumulative and increases with each
>   > subsequent packet
>   > associated with the event.
>   > In order to confirm my interpretation I investigated the
>   > behavior of some
>   > existing implementations. Some, such as MS Messenger and
>   > OpenPhone, appear
>   > to agree with my interpretation. Others, notably a product
>   > from Cisco,
>   > don't. The Cisco implementation appears to increment the
>   > timestamp for each
>   > subsequent packet and keeps the duration constant. This is
>   > the behavior I
>   > would have expected for RFC 2833 tones.
>   >
>   > My question is simple. Which interpretation is correct?
>   >
>   > Regards,
>   > Steve Lubbs
>   >
>   >
>   > _______________________________________________
>   > Audio/Video Transport Working Group
>   > avt@ietf.org
>   > https://www1.ietf.org/mailman/listinfo/avt
>   >
> _______________________________________________
> Audio/Video Transport Working Group
> avt@ietf.org
> https://www1.ietf.org/mailman/listinfo/avt

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