Re: [swinog] BGP hint required
Hi Fredy, On Thu, 7 Jun 2007, Fredy Kuenzler wrote: I'm building the CDN for Zattoo and as it's some sort of 'anycast' infrastructure (refer to the presentation @ SwiNOG #14), I have several geographically dispersed network islands, not connected via a layer-2 link. Each network island propagates one or more /24 networks, using AS8302. Now, BGP mechanism prevents AS-pathes like ^[Transit-AS]_8302$ in my case ^13030_8302$ if I'm AS8302 myself. I know there is some tweak to prevent this default behaviour. Could anyone give a hint for Foundry and Cisco gear? you may want to use the allowas-in statement in the neighbor configuration (at least on cisco) allowas-in Accept as-path with my AS present in it - neighbor 1.2.3.4 allowas-in Kind regards, Michael -- Michael Horn Network Consulting | nibbler.de | I route, therefore you are + Po.Box 810221 | 90247 Nuremberg | GSM: +4916 | FAX: +49162345 A5BF5243 2FDD653C 6A9AEE9B 1FABD08E AC1D95F2 - one you trust is one of us ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Re: [swinog] BGP hint required
Fredy Kuenzler wrote: I'm building the CDN for Zattoo and as it's some sort of 'anycast' infrastructure (refer to the presentation @ SwiNOG #14), I have several geographically dispersed network islands, not connected via a layer-2 link. Each network island propagates one or more /24 networks, using AS8302. Now, BGP mechanism prevents AS-pathes like ^[Transit-AS]_8302$ in my case ^13030_8302$ if I'm AS8302 myself. I know there is some tweak to prevent this default behaviour. Could anyone give a hint for Foundry and Cisco gear? Normally BGP speakers MUST not be able to disable loop prevention. You're probably thinking of no bgp enforce-first-as but that's not relevant here. There was another hack related to network transitions and have two ASs configured at the same time. Though I don't know if this is good enough either. As an alternative you can have a static route for your entire anycast netblock to one of your upstreams. That fixes the immediate issues but doesn't provide load balancing or failover. -- Andre ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Re: [swinog] BGP hint required
Fredy Kuenzler wrote: I'm building the CDN for Zattoo and as it's some sort of 'anycast' infrastructure (refer to the presentation @ SwiNOG #14), I have several geographically dispersed network islands, not connected via a layer-2 link. Each network island propagates one or more /24 networks, using AS8302. Now, BGP mechanism prevents AS-pathes like ^[Transit-AS]_8302$ in my case ^13030_8302$ if I'm AS8302 myself. I know there is some tweak to prevent this default behaviour. Could anyone give a hint for Foundry and Cisco gear? Ah, here it is. It may work with some tweaks. http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a008045565b.html http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00800949cd.shtml -- Andre ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Re: [swinog] BGP hint required
Michael Horn schrieb: Now, BGP mechanism prevents AS-pathes like ^[Transit-AS]_8302$ in my case ^13030_8302$ if I'm AS8302 myself. I know there is some tweak to prevent this default behaviour. Could anyone give a hint for Foundry and Cisco gear? you may want to use the allowas-in statement in the neighbor configuration (at least on cisco) allowas-in Accept as-path with my AS present in it - neighbor 1.2.3.4 allowas-in Thanks Michael and Ueli, who pointed me to the same command. This in fact fixes the issue, at least on Cisco. No I have to find the similar command on Foundry. Best regards, Fredy ___ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
