North American Network Operators Group

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Route filters, IRRs, and route objects

  • From: Przemyslaw Karwasiecki
  • Date: Wed Mar 27 13:57:31 2002


I would like to ask you for an advice in regards to 
"proxy registering" of customer route objects in IRR.

What is the best current practice in a situation, 
when your customers want to advertise to you several
/18 or /19 but they also have a requirement to be able
to advertise some deaggregated routes on top of aggregates.

It is very common that they are unable to predict exactly 
which deaggregated routes they will need to advertise,
as they use those to achieve some traffic engineering 
objectives which change over time. And "over time" does
NOT occur once per 30 minutes or so, so they DON'T
generate any major BGP fluctuations.

Forgive my ignorance, but is my understanding of RPSL
correct, that it should be possible to specify routes
in a way which will allow cover aggregate plus whole
set of possible more specific routes upto certain netmask
length. Something like:^18-24

So why this is uncommon to use such notation to describe
routing policy, and use it to generate filters?

Why it is required by some providers to generate explicit,
exact route objects, in order to allow routes through
their filters?

Is it really necessary to "explode" route-sets like 
those^m-n into 2^(n-m+1) separate route objects
to meet requirements of some providers?

I believe that this is very common problem, so if there
are any places on the web with some "best practice" 
documents, please point me to them.

Thank you,