/19 addresses and redundancy

Tue Nov 11 17:34:08 UTC 1997

In message <yt4t5j8sh9.fsf at cesium.clock.org>, "Sean M. Doran" writes:
>Phil Howard <phil at charon.milepost.com> writes:
>
>> Route filtering is not the end of the world.
>
>Wow.  Times have changed.
>
>> You also need to make sure that the ISPs do not filter routes for parts
>> of their own blocks coming in from other peers.  If ISP-A did such filtering
>,
>> then their own customers will find you unreachable, as well as those in ISP-
>C
>> if ISP-C sends traffic for you into ISP-A.
>> 
>> I know of no ISPs doing such a thing
>
>Sprintlink did at one point.  It's a really good idea to do
>this in general because it mitigates the disconnectivity
>customers assigned prefixes out of one's address blocks
>will suffer if and when someone accidentally(?) announces
>subnet of those blocks.
>
>Inbound filters can be adjusted, you know.  Unfortunately
>the people who have inbound filters have never figured out
>that they should make this a service that they charge for.
>
>However, since inbound announcement filtering is a game
>anyone can play, I recommend people consider the
>implications of fee-based filter updating and how it can
>effect their routing whether or not they are the ones
>doing the inbound filtering.
>
>Connectivity = bidirectional bandwidth + bidirectional reachability.
>
>Connectivity = value.
>
>	Sean.

Since you would need some type of settlement system in order for
this to work, if you could get a third party to maintain the access
lists information, and manage the settlements, then you might have something.
I.e. a third part, Neutral Settlement Authority (NSA), uses a database
such as the IRR to maintain a set of policy statements, that are readable
by the rest of the Internet,  They convince a few providers, say
Sprint and Digex, to listen to them for prefix length filter exceptions,
in return this Neutral Settlement Agency, pays these providers for this
service.  The Neutral Settlement Agency then, posts to Nanog, or
other lists, saying it will cost you X dollars to have your execption listed
with us at some cost of what the costs to providers A and B are paid plus
some percentage for profit.

Looking at this, pretty much any BGP speaking peer at the MAE could do
it with the correct configurations, and the RA service could do it also,
although there are those that won't touch an RS with a 10 AS BGP path
extension, although perhaps if they were getting paid for it...

The biggest problem I see with prefix charging is the many to many
contract nature, which is where a MLPA type situtation is helpful,
but must be setup so that different providers can negotiate different
rates, as network sizes differ, and the cost to carry those prefixes
internally varies.

---
Jeremy Porter, Freeside Communications, Inc.      jerry at fc.net
PO BOX 80315 Austin, Tx 78708  |  1-800-968-8750  |  512-458-9810
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