RE: [Sipping] draft-ietf-sipping-ToIP-00

Peter,
I am glad you are looking at details of sipping-toip.

The figure 1000 in the sdp line
>      a=rtpmap:98 t140/1000
is indeed a clock rate.

You can read more about it in:
http://www.ietf.org/internet-drafts/draft-ietf-avt-rfc2793bis-09.txt
Where some requirements are stated for handling the timestamps.

Even if it has little meaning for a text packet where text characters are stored at the
moment they are created rather than by being sampled, we did not want to deviate from
normal RTP usage of that parameter.

The clock is used for setting the timestamp of the text packets, and for calculation of
time offset for redundant text, and can thus be used if there is a desire to time the
display of characters.

------

Do you see a need for negotiation of the transmission interval?

Regards

Gunnar

-------------------------------------------
Gunnar Hellstrom
Omnitor AB
Renathvagen 2
SE 121 37 Johanneshov
SWEDEN
+46 8 556 002 03
Mob: +46 708 204 288
www.omnitor.se
Gunnar.Hellstrom@Omnitor.se
--------------------------------------------

>-----Original Message-----
>From: sipping-bounces@ietf.org [mailto:sipping-bounces@ietf.org]On
>Behalf Of Peter Ridler
>Sent: Tuesday, December 28, 2004 6:08 PM
>To: IETF Sipping
>Subject: [Sipping] draft-ietf-sipping-ToIP-00 - Section 8.4
>
>
>Hi,
>
>In section 8.4 of this draft states::
>
>--.--.--.--.--.--.--.--.--.--.--.--.--.--.--.--.--.--.--.--.--
>
>Text capability SHOULD be announced in SDP by a declaration in
>line with this example:
>
>      m=text 11000 RTP/AVP 98 100
>      a=rtpmap:98 t140/1000
>      a=rtpmap:100 red/1000
>      a=fmtp:100 98/98/98
>
>Characters SHOULD BE buffered for transmission and transmitted
>every 300 ms.
>
>--.--.--.--.--.--.--.--.--.--.--.--.--.--.--.--.--.--.--.--.--
>
>On SDP line 2 (a=rtpmap:98 t140/1000) what does the 1000 stand for?
>
>Nominally it is the clock rate.  If just a filler, could it be the
>Timeout value i.e. 1000 = 1000ms or better yet (a=rtpmap:98 t140/300)
>300 = 300ms timeout value?
>
>Thanks
>Peter
>
>
>
>_______________________________________________
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>

_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use sip-implementors@cs.columbia.edu for questions on current sip
Use sip@ietf.org for new developments of core SIP

RE: [Sipping] draft-ietf-sipping-ToIP-00 - Section 8.4