Subject: RE: [midcom] draft-ietf-midcom-requirements-01.txt

From: "Christian Huitema" <[email-masked]>
Date: Mon, 25 Jun 2001 08:52:11 -0700

> > Section 6.2 talks about Deregistration. Is this suppose to be an
> explicit
> > function or is this normal closing of the MIDCOM Session? If it is
> normal
> > closing, I disagree with the requirement to close all the pin holes
(see
> > above).
> 
> I think there was some earlier discussion of this point. The point
about
> Agent de-registration is that the session between the Middlebox and a
> specific Agent has come to an end. (This is not the same as an
individual
> application session across the Middlebox has come to an end as the
> relationship between an Agent and Middlebox may survive multiple
> individual
> "application sessions".) Rather it may be something along the lines of
the
> Agent wishes to break the relationship with the Middlebox to do a
system
> restart. In this case the Agent is sending an explicit notification to
the
> Middlebox that it wishes to come "off the air". In such circumstances
the
> Middlebox can have no future knowledge of when to close poin-holes
that
> are
> already open. It therefore seems logical to free up all the resources
on
> the
> Middlebox that the Agent had requested. i.e. close all the associated
> pin-holes. Otherwise when the Agent disappears in such circumstances
the
> Middlebox will not know what to do.

This problem is an artifact of the editors' decision to write a
"protocol architecture" rather than a "protocol requirement." The
requirements that they are trying to address should be listed under an
"operational requirement" session. The issue you are handling regards
the amount of fate sharing that should be accepted between the "midcom
agent" and the "application flow". Should the application be
automatically disconnected if the midcom agent becomes unavailable? Can
a pinhole opened by one midcom agent be closed by another one? Do we
require a mechanism to produce an inventory of pinholes, in order to
enable "garbage collection"? Do we require that all pinholes have a
limited time-to-live?

-- Christian Huitema

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