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Re: [RRG] IPv4 shortage, new features and IPv6 inevitability




[Catching up on old threads...]

On Nov 21, 2007, at 7:59 PM, Robin Whittle wrote:

I understand (can someone confirm this?) that the CPU and memory
burden on each DFZ router scales roughly in proportion to the number
of prefixes multiplied by the number of peer routers, with a
significant contributing factor being the number of changed
advertisements.  This last factor is driven by outages, permanent
changes in network structure and in particular by a small subset of
operators chopping and changing their advertised prefixes between
different routers on an hourly or daily basis to achieve Traffic
Engineering of incoming traffic.


I can confirm that. Each BGP speaker needs to store per-prefix, per- neighbor state. Implementation hacks make the amount of such state very much non-linear, so direct proportionality isn't appropriate, but those are indeed the contributing variables.

Tony

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