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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: solving problems instead of beating heads on walls [was: something about arrogance]
If he would buy transit from *2* providers in 2 cities, he'd be fine, as he could announce the longer prefixes the rest of the internet does not need to see on either ISP1's backbone or ISP2's backbone or both to influence how much traffic he takes inbound on each link on each city, and how much traffic he has to haul back across his link that connects the two cities. If he loses the link between the cities each ISP will see the longer prefixes, and routing should still work. But with only 1 ISP link in each city (1 upstream) if he ever loses the link between the two cities, he has a problem, as there is no way to transfer traffic bound for city1 that enters city2's connection, and vice versa. As I said before, a gre tunnel between the 2 cities ISP connections can serve as a backup physical link and allow traffic that comes in the wrong city to get pushed back over to the right city. a gre tunnel will allow the 2 routers to appear to be directly connected, and you wont get the routing blackhole that occurs when ISPs that *dont* accept his more precise (longer prefixes) toss the packets back toward the /20 that the packets cam from. Again, one needs to engineer ones network to work around one's own failures. I.e. ask or expect don't push routes into other people's tables because you are too cheap to buy a backup pipe, or too lazy to config a gre tunnel. -jon On Sat, 27 Jul 2002, Brad Knowles wrote: > > At 10:56 AM -0400 2002/07/27, Andy Dills wrote: > > >> Are you suggesting that either of those (which don't violate any > >> RFCs) options are better than de-aggregating my /20? > > > > The best solution is just as everybody here has suggested. Use the same > > provider for transit at both locations, announce your /20 normally, and > > your more specifics with no-export. > > I'm probably demonstrating my ignorance here (and my stupidity in > stepping into a long-standing highly charged argument), but I'm > completely missing something. For reasons of redundancy & > reliability, even if you were to buy bandwidth in only one location, > wouldn't you want to buy it from at least two different providers? > > If you buy bandwidth from two different providers at two > different locations, this would seem to me to be a good way to > provide backup in case on provider or one location goes > Tango-Uniform, and you could always backhaul the bandwidth for the > site/provider that is down. > > > So, what am I missing? > > -- C. Jon Larsen Chief Technology Officer, Richweb.com (804.307.6939) SMTP: [email protected] (http://richweb.com/cjl_pgp_pub_key.txt) Richweb.com: Designing Open Source Internet Business Solutions since 1995 Building Safe, Secure, Reliable Cisco-Powered Networks since 1995
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