selective auto-aggregation

Thu Apr 17 20:32:27 UTC 2003

Only 1 question:
What about the companies that have a /24 out of the /20 0r /21 that are multi-homed?
If the route rules are not carefully prepared the multi-homed customer then might be single-homed and tied to the upstream they got the IP's from.

Thoughts?

Jim

>-----Original Message-----
>From: bdragon at gweep.net [mailto:bdragon at gweep.net]
>Sent: Thursday, April 17, 2003 3:56 PM
>To: nanog at merit.edu
>Subject: selective auto-aggregation
>
>
>
>I believe we're losing the aggregation war. More and more entities are
>deaggregating, and not announcing their largest aggregates which makes
>prefix-length filtering less effective.
>
>I'ld like to propose the concept of selective aggregation, whereby
>a router can be configured to aggregate based upon rules.
>
>For example, if an RIR allocation boundary for a particular /8 is
>/21, that routes which are longer than /21 could be aggregated to
>/21 rather than discarded. Obviously, this would only be effective
>facing one's transit, since aggregating a peer would violate most
>peering agreements. In transit-free networks, this functionality would
>not be useful.
>
>Similarly, the ability to auto-aggregate contiguous networks originated
>by the same AS, which could be applied even to routes with lengths
>shorter than an RIR boundary. This functionality could be useful
>facing ones peers.
>
>This type of thing would need to be selective, since permitted
>deaggregation (no-export tagged routes with meaningful MEDs) can
>still be useful between entities which agree to such things.
>
>If we can, I'ld like to avoid a holy war on whether deaggregating
>is someone's god given right, and stick to the premise that there
>are networks who will enforce aggregation policies, and want to do so
>in the most effective manner possible.
>
>