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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Agenda suggestions?
| >Routing flaps considered harmful... | A while ago Curtis proposed a scheme for holddowns that | has a property that a holddown time associated with | a route increases with the frequency of this route | flapping -- so that frequently flapping routes getting | progressively long timeouts. This is a good idea, if a bit of a gross and ugly hack at one aspect of the problem (frequent flaps of one specific set of prefixes). There are also ways of helping out right now that aren't dependent on implementation changes to router software and are better general fixes for the sheer number of flaps, imho. Part of what needs doing is a decision about what should give a host unreachable/network unreachable message. Right now it tends to be a box very close to the originator; I would tend to argue that this is no longer necessarily a good idea, and that in the case of statically-routed single-homed internets a box as close as possible to the destination could do that job just as well (with side effects like fewer globally-visible route-flaps). This dovetails into the new religion that doing BGP or other dynamic routing with singly-homed customers is a bad idea, even for policy or political reasons. If it's *really* necessary to do this (people argue that, among other reasons, this is something that should be done so that the CIX router can distinguish CIX member routes from non-CIX-member routes belonging to non-CIX-member resellers), it probably would be better to route them statically and advertise a lie saying that the routes originated in e.g. BGP or EGP with AS XXXX. Sean.
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