Re: [RRG] Micronet & MAB terminology; MAB sizes and Ivip flexibility

[Scott Brim <swb@employees.org>]

Excerpts from Robin Whittle on 13 Nov 2007:
> In order to make discussion of ITR-ETR schemes easier and clearer, I
> suggest we adopt two terms:
> 
> Micronet
> 
>    Following Bill Herrin's use of this term, this is a block
>    of addresses which have a single entry in the mapping
>    database, and are either tunneled to a single ETR, or
>    for which there is one body of mapping information regarding
>    multiple ETRs, with different priorities.

- When you say "tunneled" to an ETR, what do you mean?  An ETR will
  strip a containing encapsulation and route based on the (then)
  outermost headers.  Are you saying your "micronet" always has yet
  another level of encapsulating header, between the ETR and the
  ultimate destination?  

- You are making an assumption about database organization.  It would
  be more efficient to have a single database entry, organized by EID
  prefix, with all information.  If you are positing that there might
  be a reason to have separate database entries for a single prefix
  with different priorities, please justify.  I assume "the database"
  means the authoritative information from which protocol messages are
  generated, not the protocol messages themselves or whatever other
  nodes might cache as a result of receiving those messages.

In any case I think this term is confusing and probably not helpful.
The term "microNET" implies that it describes a network.  Instead you
explain it in terms of a "block" of addresses ... which could be part
of a network or spread over several.  So already there is a gap
between what you are describing and the name you are applying.
Second, you tie that term to a particular way to organize information
about it.  Please figure out what it is you are trying to define -- a
topological arrangement, a database entry, or what.

> MAB - Mapped Address Block

... etc.  It seems like you want a new term because you want to be
able to have database entries for address ranges that span more than
one prefix.  Why not just say "address range"?

And the idea of routing on ranges instead of prefixes was discussed
for years and discarded as unnecessary.

> In IPv4, MABs are likely to be at least 256 addresses long, since
> this is currently the smallest range of addresses which can be
> either removed from the BGP system, or handled as a unit by it.
> (I understand there is no formal definition of this /24 limit on the
> advertisements BGP routers are typically configured to accept, but I
> think it is a restriction which is likely to endure for a long time.)

Operational conventions for the use of BGP are tailored to its use in
mainline Internet routing, including the need to control rate*state.
They should not be assumed to apply to other uses of BGP -- if BGP is
used at all.

So what I see in this message is terminology we don't need and a
suggestion that was dealt with years ago.

swb

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