Subject: [MMUSIC] SDP session expiry after 30 minutes - is this ever used? was Re: 2 and a half SDP questions

From: <[email-masked]>
Date: Mon, 26 Jul 2010 13:45:53 +0200

Hi All

The title says it all - but for more see below...

Cheers, Rod.

Walsh Rod (Nokia-NRC/Tampere) wrote:

Hi All

1. Can someone clarify bandwidth modifier usage with slash notation.
i.e. AS and TIAS meaning at session and media level are well enough
specified, but SDP use of slash notation (IP/TTL/number_of_IPs,
port/number_of_ports) leads to an ambiguous situation. e.g. if an SDP
has 2 m= lines, the first has one port and one IP address (on a c= line)
but the second uses slash notation to specify two IP addresses then we
have 3 media flows. AS or TIAS at media level can specify bandwidth for
the first but for the 2nd and 3rd we have no specification text to
disambiguate! The most obvious option is to make the AS or TIAS specify
the maximum summation of the 2nd and 3rd flows. But is there any example
that deals with separately specifying bandwidth per flow of a media line?

2 (& 2.5). SDP provides guidence that session identifiers should not be
reused until 30 minutes after the session t= end time (and likewise from
before the start time). Is this considered best practice and widely
used? What is the underlying assumption on clock synchronisation between
source and sink? When the time is unbounded at start or end (i.e. = 0),
how - if at all - is that 30 minute guidance used?

Thanks in advance,
Rod Walsh.

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From: <[email-masked]>
Date: Mon, 26 Jul 2010 13:49:23 +0200

Hi again

Slash notation with bandwidth modifiers in SDP leaves room to break things. Has someone dealt with this as a problem or solution?

Cheers, Rod.

Cheers, Rod.

Hi All

Thanks in advance,
Rod Walsh.