Subject: Re: [MOBILE-IP] MIER V01

From: Patrice Calhoun <[email-masked]>
Date: Tue, 7 Dec 1999 14:05:17 -0800

>Hello,
>
>Responses prefixed by >>>
>
>--Raja
>
>----------------------------------------------------------------------------
>---
>
>All,
>
>Although this draft is better than its predecessor, I REALLY don't like the
>way that the one octet is split up into a sub-type and flags.
>
>I really don't see why a reserved bit field is necessary, and this limits
>the
>number of sub-types to 16.
>
>>>> Well, the reserve bits are a nice way to facilitate some future
>standization efforts for types that have already been used. Surely, we
>REALLY don't have to just address problems that are at the tip of the nose.
>Who knows, at some point someone may choose to add a flag to a type to mean
>something.

This I really don't get. Let us say that a specific extension (101) is for
authentication extensions. So we KNOW a priori what 101 really is.

Then we have another extension (102), which contains NAIs. Well we KNOW a
priori that this contains an NAI because it has a type of 102.

So, I really don't see why a bit field could be used to represent the
object type. I don't think that we are really trying to achieve a self
defining type, right?

>
>>>> Having said that, we are open to the sentiments of the WG. If the
>consensus is that reserve bits are useless then we would be more than happy
>to take it out.
>
>This seems to conflict with the statement in
>the abstract "MIER describes a new extensions structure to Mobile IP to
>make the extensions truly extensible." I think that truly here is a little
>mis-leading since it is not infinitely extensible. We still have a maximum
>number of extensions, and what we now have is 254 * 16, which should
>give us a little longer, but it's hardly "truly extensible".
>
>>>> Our original draft had a general extension which would have made it
>truly extensible. I agree that 'truly' in the context of this version can be
>reworded. We can reword it or re-introduce the general extension concept now
>or at a later stage -- which ever the WG desries. Don't agree with the
>comment that 254 * 16 would give us a 'little longer' ... 16 times what we
>have today is non trivial.

I wan't saying that it wasn't enough, simply that truly was too strong a word.