Subject: comments on the requirements draft

From: Eliot Lear <[email-masked]>
Date: Wed, 19 Dec 2001 16:43:51 -0800

Section 3.1.3 Performance:

>    For example, suppose site E obtains transit from transit providers T1
>    and T2, and there is long-term congestion between T1 and T2.  The
>    multihoming architecture MUST allow E to ensure that in normal
>    operation none of its traffic is carried over the congested
>    interconnection T1-T2.  The process by which this is achieved MAY be
>    a manual one.

Why are we adding the caveat of the last sentence?  Manual anything is bad.

In section 3.2.1:

>  A new IPv6 multihoming architecture MUST scale to accommodate orders
>    of magnitude more multi-homed sites without imposing unreasonable
>    requirements on the routing system.

This is redundant.

Sections 3.2.2 and 3.2.3 presume a real installed base.  There is none.

Section 3.2.5 also sounds either redundant or unworkable.  If what you mean 
is that you must be able to retrieve routing information from a router, 
then fine.  If what you mean is that administrators should be able to 
remotely manage and monitor end systems for purposes of multihoming, that's 
a whole other kettle of fish.

Section 4  Security Considerations

This seems overly broad.  I think what you mean is the following:

    It MUST be theoretically possible to deploy a multihomed site that
    is no less secure than a single-homed site.

Anytime a routing protocol is involved there are bound to be more sensitive 
points of attack (like DDOS, for instance).  Just like anything else, 
multihoming can be done poorly.

Good luck,

Eliot

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From: Brian E Carpenter <[email-masked]>
Date: Thu, 20 Dec 2001 11:09:56 +0100

Eliot Lear wrote:
...

> Sections 3.2.2 and 3.2.3 presume a real installed base.  There is none.

No, they recognise the existence of a significant number of implementations.
I work with development managers for host stacks, and I guarantee you
they are not about to start over - multihoming has to be an add-on, if
you want it to happen. I presume the same is true of router code.

To me these are absolutely key requirements if you want multi6 to have
any impact on the real world.

  Brian

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From: Eliot Lear <[email-masked]>
Date: Thu, 20 Dec 2001 08:08:38 -0800

Then you're being penni-wise and pound foolish.  If not deploying 
multihoming means we exceed Moore's law over some period of time, we're all 
in trouble.  Let's evaluate solutions based on their technical merit, and 
not on the amount of code that will need to be written.

Eliot

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From: Brian E Carpenter <[email-masked]>
Date: Thu, 20 Dec 2001 17:36:53 +0100

Eliot,

In almost all cases I would agree with you. And it may well be
that 5 or 10 years from now, people will have got enough
revenue from IPv6, or will have such compelling customer input,
that they rewrite their stacks for multihoming. But in the 0 to 5
year timeframe, I don't expect stacks to get rewritten.

  Brian