[ipv6-wg at ripe.net] Re: [lir-wg] IXP networks routing
Måns Nilsson mansaxel at sunet.se
Wed Mar 5 22:49:15 CET 2003
--On Wednesday, March 05, 2003 22:27:51 +0100 Jeroen Massar <jeroen at unfix.org> wrote: > Case one means having more than one prefixes on the cable, > or in diagram style: > > +-----+ +-----------+ 2001:db8:11:22::/64 +------+ >| the +---+ Cable ISP +------------------------+ eth0 | >| N | +-----------+ | | >| E | | YOU | >| T | +-----------+ 3ffe:ffff:33:42::/64 | | >| +---+ ADSL ISP +------------------------+ eth1 | > +-----+ +-----------+ +------+ > > Thus YOU gets 2 different prefixes from 2 different upstreams. > Ofcourse YOU could also get two /48's routed to him from these > upstreams or more ofcourse. The fact is that a 'server' eg > a web server will have 2 IP's; eg: > www.example.com AAAA 2001:0db8:11:22::80 > AAAA 3ffe:ffff:33:42::80 This is not what we are talking about. > Ofcourse replace Cable and ADSL with the bigger lines, > this is just to illustrate that the definition of 'multihoming' > is quite a different thing for most people. As I said this > will only work when using SCTP to 'multihome' when one of the > two uplinks fail. > > In case two both upstreams carry "your" prefix, eg 2001:db8:11:22::/64 > to the rest of the world, diagram style: > > +-----+ +-----------+ 2001:db8:11:22::/64 +------+ +------+ >| the +---+ Cable ISP +------------------------+ R | | | >| N | +-----------+ | o | | | >| E | | u +----+ eth0 | >| T | +-----------+ 2001:db8:11:22::/64 | t | | | >| +---+ ADSL ISP +------------------------+ er | | | > +-----+ +-----------+ +------+ +------+ This is more to the point. > Note that the moment you only have one physical path to the rest of > the world you should not be talking about 'multihoming' any more (case > 3) > > I always wonder why people want L3 level 'multihoming' even though > their L1 and L2 path aren't. Because even if backhoes are quite common creatures, the network engineer with fat fingers is even more common. Having said that, I agree that several redundant links are a practical prerequisite. >> Although my idea is to give people so much space in their initial >> allocation that only the biggest networks will need more than >> one prefix, thus keeping the routing table as close to >> "nPrefixes == nAS-numbers" as possible. > > Every ISP that can match up to the current requirements for address > space > can get a /32 from all three RIRs. If you can't, you simply are not big > enough and you won't have any multiple links either. Which is my point, sort of. But I still want the requirements slacked to fuel deployment. > If one really wants 99.9% certainty that their inet works one either > needs > to do it themselves and thus get multiple L1+L2 paths and the hardware > along > with it and then most of the times you are a big enough customer to get > a > /32 too. If you aren't you should just get a better upstream. > Yes, I know, it all sounds quite harsh. No disagreement there. But I do not think we talk about the same thing, or at least not in the same scale. -- Måns Nilsson Systems Specialist +46 70 681 7204 KTHNOC MN1334-RIPE We're sysadmins. To us, data is a protocol-overhead. -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 187 bytes Desc: not available URL: <https://www.ripe.net/ripe/mail/archives/lir-wg/attachments/20030305/5816380f/attachment.sig>
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