[AVT] Another question on RFC 4103

Marc Petit-Huguenin <petithug@acm.org> Sat, 18 April 2009 15:29 UTC

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Date: Sat, 18 Apr 2009 08:31:00 -0700
From: Marc Petit-Huguenin <petithug@acm.org>
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Subject: [AVT] Another question on RFC 4103
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RFC 4103 does not give any advice on what to do when a t140block to
send will create an RTP packet that will exceed the PMTU.  Should
the PMTU be considered as an implicit maximum character transmission
rate, or should multiple RTP packets with the same timestamp be
sent? (for the latter there is the additional issue that RFC 2198
does not provide any advice on the same problem).

For example let say that the cps is 30 and the PMTU is unknown so
576 bytes is the maximum IPv4 packet size that can be sent.  With 30
cps and a language that makes use of three bytes per character, the
maximum block size is 900 bytes which is more than the maximum IPv4
packet size without even counting the overhead.  In this case the
maximum implicit cps would be 17 cps.

-- 
Marc Petit-Huguenin
Home: marc@petit-huguenin.org
Work: petithug@acm.org