North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: The Cidr Report
> Tli asked: > > | Exercise for the reader: If prefixes of length F and longer are filtered, > | and a domain has a prefix of length N, how many prefixes can they propagate > | into the backbone? How many before people start proxy aggregating them? > > A/ (2 ** F) - 1. [assuming nobody imposes exact-match prefix filters] > > B/ When we can easily do: > > "router bgp N > proxy-aggregate route-map Lazy-Types I may be misunderstanding, but does this (proposed) config statement automaticly suppress (aggregate) any prefixes that are exactly the same as another prefix except in the length? For example given 128.8.0.0/16 128.8.0.0/24 128.8.1.0/24 the last two would not be propogated? That would be cool! Erik > > ! exceptions > route-map Lazy-Types deny 10 > match as-path 100 > > ! the rule > route-map Lazy-Types permit 20 > match originated-prefix-count 16" > > then the number 16 strikes me as a starting point, > although I probably want to re-read Dennis's comments > from a few years ago. > > Do I pass? > > Sean. >
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