Vadim Antonov wrote:
>On Mon, 15 Jul 2002, Pedro R Marques wrote: > > > >> From a point of view of routing software the major challenge of >>handling a 256k prefix list is not actually applying it to the >>received prefixes. The most popular BGP implementations all, to my >>knowledge, have prefix filtering algorithms that are O(log2(N)) and >>which probably scale ok... while it would be not very hard to make >>this a O(4) algorithm that is probably not the issue. >> >> > >Mmmm... There's also an issue of applying AS-path filters which are (in >cisco world) regular expressions. Although it is possible to compile >several REs together into a single FSM (lex is doing exactly that), I'm >not sure IOS and/or JunOS do that. > >--vadim > > > > My comment implied 'prefix-lists' which i believe was what the original poster refered to. Assuming that the primary key is a prefix, i believe all major implementations can perform this efficiently. I do agree with you that whenever the intended primary key is something else most implementations do not have an efficient way of expressing this. Route-maps and policy-statements in Juniper-parlance are sequentially evaluated, rule by rule. I would still contend that the number 1 issue is how you do express the policy to the routing code. One could potentially attempt to recognise the primary key is a route-map/policy-statement and compile it as you suggest. It is an idea that ends up being tossed up in the air frequently, but would that solve anything ? Is there the ability in the backend systems to manage that effectivly and if so is text interface via the CLI the most apropriate API ? regards, Pedro.