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  • From: Cengiz Alaettinoglu
  • Date: Fri Nov 15 13:35:49 1996
  • Posted-date: Fri, 15 Nov 1996 10:08:08 -0800

I build the router configuration tool that most providers use.  I also
build quite a few analysis and diagnosis tools using IRR.  I will
respond to this message from that perspective of a tool builder.

Brian Merritt ([email protected]) on November 14:
> How many providers are basing their policy solely on IRR information? Are
> these providers (if they exist) at all concerned with the notion that (if
> the RA statistics on IRR violations are at all useful) they may not be
> able to get to up to 25% of the Internet at any one time? Might the IRR be
> more harmful than goodful if it's actually used to generate router
> config's by any small group of providers, and not by everyone? (Unless you
> think segmentation is good). Is the IRR more valuable as a "source of
> information for analysis and debugging tools" than as a source of
> information to base routing policy on?  I would say apparently so. Is the
> IRR supported?  Well, as far as I can tell almost everyone that should be
> participating (in some form) is.  Is it supported in the sense that
> everyone that is participating is commited to maintaining accurate
> information? I would say apparently not. Is it supported in the sense that
> it is actually used for anything other than "analysis and debugging"? (And
> what sort of useful analysis can be done with data that is 25% bad
> anyhow?) I don't know. Should the IRR be used for anything presumed to be
> "actually useful"? Well, I certainly wouldn't rely (solely) upon it. How
> about you? If the IRR were useless would it break the Internet? Nope. 
> Could the IRR improve the Internet if it were used by everyone? Maybe. 
> Should the IRR exist? I think yes. 

There are quite a few providers who are using RtConfig to configure
their routers. There are providers who have their own configuration
tools as well. So far, everyone who has given me feedback on using
RtConfig to configure their production routers have been positive and
enthusiastic about it. They find it to be a lot simpler/more manageable
to specify policies at the high level and generate low level router
configurations from it than configuring each router individually and
maintaining consistency across them.

The data needed for these providers are all accurate.  An in some case
the data become even more accurate after they started using the tools.

Is the data 100% accurate? No. Would it help if it were?
Definitely. We have written a tool to analyze the policies and the
Internet topology in IRR and aggressively suggest CIDR aggregations
which do not break routing. This tool is an important one, because
Internet is growing, the topology is becoming more complex, and more
and more fraction of the engineers are not up to speed on cidrization.
However, this tool needs close to 100% accurate policies to work
effectively. Otherwise, the routing may break (with small probability
since the tool is very pessimistic when the policies are missing).

Recently, we focused on tools to make IRR more accurate. We built roe,
route object editor. A provider by feeding a routing table dump, can
fix most of its incorrect route objects by few mouse clicks. aoe,
autonomous system object editor, will be released soon which tries to
do the same for the aut-num objects.

My few Liras.


Cengiz Alaettinoglu           Information Sciences Institute
(310) 822-1511                University of Southern California
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  • References:
    • IRR Brian Merritt