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Re: Route table growth and hardware limits...talk to the filter

  • From: Michael Smith
  • Date: Fri Sep 21 12:13:07 2007


Hello Pekka:


On Sep 21, 2007, at 7:18 AM, Pekka Savola wrote:


On Fri, 21 Sep 2007, Randy Bush wrote:
Meanwhile, I have brought myself to three options:
Has the option of using default route(s) occurred to you?

welcome to v6. we forgot to sort out routing, so just don't do it. you're kidding, right?

No, I'm not kidding but maybe we're talking about a different thing (you may have a more generalized network in mind).


The way I see it, a network which is considering "Juniper M7i or Cisco 7300 plus a couple of switches" as an option does not _need_ 220K IPv4 routes in its routing table. Whether it has 150K, 40K (Hi Simon!) or 5K shouldn't matter that much from the functionality perspective.

If we still disagree, it might be interesting to hear why filtered BGP feeds from upstream and appropriately placed default routes to cover the holes wouldn't provide a functionally and operationally an equivalent solution?

Well, how do you determine which routes to select from each provider and what to cover with defaults? How do you modify those settings once they're in place, particularly when you find exceptions in your design? I know the answers, but these are not easy questions to answer if you are a small provider that is smart enough to have multiple transit providers and enough clue to configure .* and ^$, but not enough clue to filter based upon upstream provider communities, flows and/or other dynamic means.

The whole point of BGP, to my mind, is so that I *can* accept full routes from multiple providers and *may* elect to change that behavior for other reasons. I shouldn't have to modify my BGP configuration to support my vendors' inability to provide a device that can scale to the present demands of the global routing table. Last time I checked, they are here to support me, not the other way around.

Regards,

Mike