From: Spencer Shepler (shepler@eng.sun.com)
Date: 09/10/01-08:21:56 PM Z
Date: Mon, 10 Sep 2001 20:21:56 -0500
From: Spencer Shepler <shepler@eng.sun.com>
Subject: Re: Delegation callbacks proposal
Message-ID: <20010910202156.R514@d-mpk17-86-138.eng.sun.com>
On Mon, Brent wrote:
>
> I don't think there's any doubt that we do have a problem: the callback
> mechanism conflicts with the charter. We need to reach some consensus
> on a solution. If not connection re-use, then what else will fix
> the problem ?
I am not convinced that this is a "problem" that we need to solve
today. The re-use of the connection for the callback path is
something that would fit nicely into a minor version of the protocol.
The proposed solution is not new to the working group (As Mike E. has
provided reference to) and it is certainly not something new to the
authors of the RFC as evidenced by these sections of RFC3010:
1.1.6. Client Caching and Delegation
8.3. Blocking Locks
"must not rely on a callback mechanism"
9.2. Delegation and Callbacks
"Because callback RPCs may not work in all environments (due to
firewalls, for example), correct protocol operation does not depend
on them. Preliminary testing of callback functionality by means of a
CB_NULL procedure determines whether callbacks can be supported. The
CB_NULL procedure checks the continuity of the callback path. A
server makes a preliminary assessment of callback availability to a
given client and avoids delegating responsibilities until it has
determined that callbacks are supported."
9.2.1. Delegation Recovery
o The use of callbacks is not to be depended upon until the client
has proven its ability to receive them.
Since RFC3010 is a Proposed Standard, it has received the normal IETF
review cycle and the issue of failure to have the callbacks work with
NAT or firewall present.
I am not saying that the proposed idea isn't worthwhile; I just don't
think that given the history of developing the protocol and the list
of things that need to be addressed for correctness that it is the
best time to change the callback mechanism.
--
- Spencer -
This archive was generated by hypermail 2.1.2 : 03/04/05-01:49:05 AM Z CST