Subject: [MMUSIC] ICE keepalive potential issues

From: "Jean-Francois Mule" <[email-masked]>
Date: Thu, 9 Nov 2006 16:07:36 -0700

This is a follow-up on one of the issues presented at the meeting
today (the slide 18 of
http://www3.ietf.org/proceedings/06nov/slides/mmusic-2.pdf).
There was rough consensus to go with the slide proposal to loosen up the
requirements for keepalives and for using binding indications of 3489bis
which is still a worthwhile optimization. 

That said, the slide presents a potential issue with some layer-2 access
networks like DOCSIS cable networks that may provide media streams QoS
at layer 2 using unsolicited grant services. 
After reviewing some DOCSIS specs and discussing the use case with Kevin
Johns, this should be a non-issue for DOCSIS:
	- if the agent has to send an ICE keepalive, or keepalive ack on
top scheduled media, it just sends it,
	- at layer 2, the cable modem can request an extra grant to sent
it. The CMTS QoS scheduler will respond by issuing an extra grant (not
to exceed 1% of the provisioned bandwidth). This can be asserted
continuously or only as needed. For folks who want a reference, it is
described in more details in
http://www.cablemodem.com/downloads/specs/CM-SP-RFI2.0-I11-060602.pdf,
in section VI.1.

I write this mostly to provide more background info and close the loop.
I also want to state that the wg should probably not do special things
for special layer-2 nets...

Jean-Francois.

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