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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: "Simple" Multi-Homing ? (was Re: CIDR Report)
[ On Tuesday, May 16, 2000 at 12:09:16 (-0400), Chris Williams wrote: ] > Subject: Re: "Simple" Multi-Homing ? (was Re: CIDR Report) > > Although I agree that co-locating is probably the right solution in this > There is a whole class of human-error and miscommunication problems > which can cause an interruption of service from one provider, regardless > of how technically redundant your links to that provider are. Examples > I've directly experienced in the past year: > -- The provider finds a cancellation for an old circuit floating > around in their DB, and confusing it with your current service, shuts > down your connection (I had this happen with a prominent tier-1 provider > -- these kinds of mistakes are not just made by small no-name ISPs) > -- The provider sends your bill to the wrong address, and so your > accounting dept doesn't pay it, and they suspend your service. Those are examples of contingencies that should be covered in your service level agreement. The SLA should hold the provider responsible for any loss of income, recovery costs, or whatever, should they be the ones to screw up. Assuming you trust the provider to honour the SLA you've worked out with them then your level of risk is mitigated even if it's not done exactly in the way you might prefer under ideal circumstances -- we are talking about (hopefully exceptional) events here, after all! If you don't trust your provider to honour their agreements then I'd humbly suggest you find one you can trust! ;-) All but the last are also examples where basic link-level redundancy will help to avoid total outages. You don't need an ASN and full BGP route peering just to remain connected when your T1 goes down! Please let's solve the right problem here! > -- A box on your network is cracked and used to send SPAM. The > providers shuts you down for spamming without warning, or with warnings > sent to the wrong address. If such action is specified in your contract then you've accepted that risk and you should mitigate it appropriately (eg. by regularly testing and securing your servers!). I'd hope that if you did have redundant routing then your other provider would also cut you off for the same reason and at approximately the same time! > In any case, it seems to me we've veered significantly from the original > topic. I thought we had pretty well established that "there are some > legitimate needs for multihomed /24s" -- the question brought to the > list was really "will my /24 work if I multihome it?", not "please tell > me I don't know what I want". I'm not entirely sure I agree yet. There are lots of excuses flying around, but few real reasons. Sure you can concoct fake requirements until they add up to this being the only alternative but I don't think they'll weigh out in the long run. I think there's another alternative that's being missed here too that'll satisfy the majority of needs of quite a few people, if not most. It should be trivial to obtain only the minimum necessary address space from both providers and truly multi-home the servers requiring redundancy! For outgoing connections you simply flip the default route on each server as necessary (perhaps using automated tools) and for incoming connections you just put multiple A RRs in your DNS for each service requiring redundancy. Load balancing opportunities spring to mind here too! I.e. please let's solve the right problem! -- Greg A. Woods +1 416 218-0098 VE3TCP <[email protected]> <robohack!woods> Planix, Inc. <[email protected]>; Secrets of the Weird <[email protected]>
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