Subject: Re: [lisp] proposed draft-ietf-lisp-alt-02 draft

From: [email-masked] (Noel Chiappa)
Date: Fri, 8 Jan 2010 22:11:57 -0500 (EST)

> From: Charrie Sun <[email-masked]>

    > How does an ALT router knows which is his parent and which is the child?

I'd like to remind everyone that in discussing this point, it's important to
remember that the _protocol_ knows nothing of 'parent' and 'child' nodes: BGP
is an equal peer-peer protocol, and any 'hierarchy' that exists in the ALT
connectivity mesh is principally in the minds of the people looking at it.

Yes, to the extent that the mesh is _not_ hierarchically arranged, we will
not get the _maximum_ amount of aggregation of advertisements of mappings
(i.e. minimizing the distribution tree table size overhead - if not the path
lengths :-). So there is a point to the hierarchy...

And apologies to all to whom this was all already obvious - just wanted to
make sure that was well understood by everyone... :-)

    > I still wonder how ALT builds such a hiararchy, exclusively
    > voluntarily?
    > ...
    > Who would like to run ALT routers, and who would like to be at certain
    > level, aggregating certain range of EIDs? Is the question trivial?

No, it's a significant question, but do remember that these questions are not
questions about the protocol, but almost entirely are about the use and
operation of the system. So it falls under 'operation and management'.

Yes, IETF protocols/designs do have to have feasible operation+management
(and also economics, a point that has sometimes been overlooked in some past
designs... :-), but the IETF can only go so far in mandating how people
who deploy things actually operate on the O+M front...

This is not an answer to your question, I know; I suspect the real answer
is something like 'only the ISPs, etc, can tell us whether the framework
that LISP provides is operationally and economically viable'... So perhaps
someone from that part of the world can opine on your points?

	Noel

---

From: Vince Fuller <[email-masked]>
Date: Fri, 8 Jan 2010 20:52:26 -0800

> who deploy things actually operate on the O+M front...

And, more importantly, these questions are greatly influenced by business
decisions which are explicitly outside of the purview of the IETF. We can
decide whether a protocol provides the necessary mechanisms to implement
needed policy and infrastructure (the LISP+ALT authors obviously think that
LISP+ALT does so); we can't specify how those mechanisms are used to create
organizations or businesses.

	--Vince

---

From: Charrie Sun <[email-masked]>
Date: Sat, 9 Jan 2010 14:26:01 +0800

---------- Forwarded message ----------
From: Charrie Sun <[email-masked]>
Date: 2010/1/9
Subject: Re: [lisp] proposed draft-ietf-lisp-alt-02 draft
To: Vince Fuller <[email-masked]>

 2010/1/9 Vince Fuller <[email-masked]>

> LISP+ALT does so);

So, who would run ALT routers, ISPs? Without an implementation model or just
an analysis, how to persuade people to follow the idea?

> we can't specify how those mechanisms are used to create
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