> -----Original Message-----
> From: Erik Nordmark [mailto:[EMAIL PROTECTED]]
> Sent: Monday, September 17, 2001 1:11 PM
> To: Dave Thaler
> Cc: Erik Nordmark; [EMAIL PROTECTED]; [EMAIL PROTECTED]
> Subject: RE: uni-based-mcast and malloc-ipv6-guide
>
> > > -----Original Message-----
> > > From: Erik Nordmark [mailto:[EMAIL PROTECTED]]
> > > Sent: Monday, September 17, 2001 11:23 AM
> > >
> > > > See RFC 2908.
> > >
> > > At least that reference is missing from the document.
> > > But I see a mismatch between the draft and RFC 2908 since the
latter
> > > seems to say that an application can request multicast addresses
with
> > > a particular lifetime. With the uni-based addresses there can be
no
> > > way for the application to request a lifetime.
> > > How can this be resolved?
> >
> > What makes you think there isn't a way for the app to request a
> > lifetime?
> > RFC 2771 applies to all dynamic multicast addresses.
>
> Huh?
>
> How does the application requesting a particular lifetime effect the
> lifetime that the routers use when advertising the unicast prefix?
It doesn't.
In the abstract API, the application supplies a minimum and desired
lifetime. If the app says [0, 6 months] and the host knows that
the unicast prefix is valid for 1 week, it can tell the app it has
it for one week (and the app can renew it at any time).
> Are you envisioning some new protocol to inform the routers (and the
> system
> admin, ISP, RIR) that allocated the unicast prefix that it needs to
> stay around for long enough to satisfy the applications request? :-)
Gosh I hope not :)
> So while there might be an abstract API that allows the application
> to ask, the scheme in uni-based-mcast doesn't seem to have the pieces
> so that the system can honor such a request; at least not with a
strict
> interpretation of the relationship between the RFC 2462 notion of
lifetime
> of the unicast prefix, and the presumed lifetime of the derived
multicast'
> address.
If the app says [6 months, 6 months] then personally I would expect the
host to fail the request if it only has a unicast prefix lifetime of 1
week.
I think your question is really: should we allow such a host to grant
a request for 6 months if it only has a unicast prefix lifetime of 1
week?
In my previous email, if there is a need to allow this (and I'm not
saying
there is), then we'd have to just say it SHOULD NOT, and say that after
the unicast lifetime, the multicast packets are not guaranteed to be
routed.
> Hence my question whether the intent is to have such a strict
relationship
> or not.
I'd like to hear others opinions, but I think that is the authors'
intent.
-Dave
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