metarouting [Re: [RRG] recent progress in routing research]

[Pekka Savola <pekkas@netcore.fi>]

Again on the list to stimulate discussion...

On Sat, 20 Aug 2005, Dmitri Krioukov wrote:
> 3. Finally, I'd like to point out that importance of the research
> direction established in the breakthrough metarouting paper
> http://www.acm.org/sigs/sigcomm/sigcomm2005/paper-GriSob.pdf can
> hardly be overestimated.

I'm not sure how useful the work will be in practice, as 
implementation of these metalanguages, algebras and the necessary 
abstraction layers for the routing protocols might be more work than 
it is worth, but maybe there will be applications on this.

However, one detail disturbed me.  In section 5, BGP modelling states 
"The _med_ attribute (..) is used to implement cold potato routing. 
In order to avoid the notorious problems of this attribute [18, 26], 
we model _med_ as if this attribute is always compared, no matter what 
the next hop ASN".  That may be true, but that is hand-waving and 
misses the point.  The point for this paper (IMHO) in my opinion 
should be to prove that it can express the same things that BGP can 
do.  That includes the current MED behaviour that exists today, even 
though it can cause undeterministic scenarios.  This approach makes 
one wonder whether it is even possible to represent the real MED 
behaviour with RAML (without significant amount of extensions -- and 
the length and complexity of these extensions might give an idea of 
the practical usefulness and representative power of the language).

--
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

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