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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: BGP to doom us all
On Sun, 2 Mar 2003, Avi Freedman wrote: > In article <[email protected]> The Great Sean wrote: ^^^^^^^^^^^^^^ > : I'll be stupid, and ask some questions I've always wondered about. > : Why should routes learned by eBGP have a higher priority than iBGP? > Love to know myself. Consider the situation where two routers have an external path to a destination, but they both prefer the path over the other. This can create routing loops and BGP instability as routers keep revoking and reannouncing their external routes over iBGP. However, the "external first" rule is a relatively weak one, as it only kicks in when the BGP route selection algorithm can't decide which route is better. If you use the local preference, AS path or multi-exit discriminator to prefer one of the BGP routes, all routers will use this one, regardless of whether they learn it over eBGP or iBGP.
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