Subject: Re: I-D Action:draft-mrw-6man-ulac-analysis-01.txt

From: Brian E Carpenter <[email-masked]>
Date: Wed, 21 Nov 2007 15:56:23 +1300

> 4.2.  Wrong Way to Influence Registry Policy
> 
>    It has been argued that it is inappropriate and/or ineffective for
>    the IETF to attempt to influence address registration policies
>    through the publication of an RFC that creates a new address space
>    with defined registration policies.

That does not, however, mean that the IETF shouldn't reserve a
specific prefix for this usage if the consensus is that this is
the correct thing to do, technically and architecturally. I think we
agree that the IETF shouldn't attempt to constrain *how* the space
under that prefix is administered, but that is a separate question.

>    There is no technical advantage, and there may be some architectural
>    disadvantages (see Section 4.3), to allocating a prefix for globally
>    unique addresses with specific registration policies.

Setting aside the architectural argument, I think this second sentence
is wrong. There *is* a technical argument for having a globally defined
prefix for ULA-C, and furthermore for having it adjacent to the prefix
for regular ULA: so that equipment and software can be configured by default
to filter ULAs. You may argue that this is a weak argument, but it exists.

Nit in section 1:

>    Locally Assigned ULAs are generated within the local enterprise,
>    either by the network administrator or by a piece of networking
>    equipment, using a random number generator.  These addresses are
>    probabilistically unique, in the sense that it is extremely unlikely
>    that there will be an overlap within any reasonably small number of
>    Centrally Assigned ULA prefixes.

s/Centrally/Locally/

     Brian

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