Subject: [Isms] New revisions

From: "David Harrington" <[email-masked]>
Date: Mon, 16 Oct 2006 11:41:21 -0400

Hi,

I have been largely working in isolation, doing what we discussed at
ietf66. Unraveling a bowl of spaghetti is often easier done alone.

I have developed a transport subsystem for the RFC3411 architecture.
It is available at
ftp://ftp.rfc-editor.org/in-notes/internet-drafts/draft-ietf-isms-tmsm
-04.txt. 

I then worked at defining an SSH transport model within the transport
subsystem. It is available at
ftp://ftp.rfc-editor.org/in-notes/internet-drafts/draft-ietf-isms-secs
hell-05.txt

Having done that, I started work on the session security model to
manage the associated SNMP sessions. 

However, as I did this, separating out the notion of session for the
transport, and the notion of session for SNMP, I found that the SNMP
session had no value-add; all the value came from having a session at
the transport layer. Using a "Session Security Model" created a
binding between the session in a security model (in the security
subsystem) and the session in a specific transport model within the
transport subsystem. There really is no need for such a binding given
what we have agreed to at this point, and this violates the modular
design of the RFC3411 architecture.

Therefore, I created a new security model called the Transport
Security Model. This model does not require a session-based transport.
If the transport supports sessions, than the value of amortizing the
security costs across a session is gained; if the transport model does
not use sessions, then that benefit is not gained. But whether the
transport offers this or not is immaterial to the security model. The
only thing the security model cares about is "did the transport model
provide (at least) the requested security?"

I am not sure that the -00- draft approval met the deadline; hopefully
it will show up in the i-d repositiory within days. In the meantime,
here is a copy of the document. There is always the possibility that
the document will be modified slightly during the oublication process,
so  I renamed it here, so we can distinguish which copy is being
commented on.  
 
--
I recommend starting with the transport subsystem doucment. Since this
is just an add-on to the conceptual architecture, I think this will be
the least controversial document, and I am hoping it will be accepted
by WG consensus so I can stop editing this document soon. 

I recommend reading the SSH document second, checking to make sure it
fits within the transport subsystem properly. The issue of session
reuse and call-home and so on should be limited to this document now.
That should make it somewhat easier to deal with.

The Transport Security Modal is basically new, and may be
controversial. We need to verify that this security model works with
SSH, and to ensure that it could work with other transport models. I
think this is a "shim" model - it does not provide much functionality,
it just provides the glue from the functions provided by transport
models to the SNMP engine, using the 5-tuple (transportType,
transportAddress, secuirty Model, securityName, securityLevel).

Most of the open issues are still open; breaking the functionality
down into these modules  will hopefully help us focus on those issues.

The documents are not as "finished" as I would have liked, but ietf67
deadlines forced me to publish now.

I look forward to your reviews.

David Harrington
[email-masked] 
[email-masked]
[email-masked]
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