Route table growth and hardware limits...talk to the filter
Lincoln Dale
ltd at interlink.com.au
Sun Sep 9 23:35:51 UTC 2007
> > what i think it boils down to is that many folks seem to run default-free
> > because they can, because its cool, because its what tier-1 folks do,
> because
> > (insert cool/uber reason why here), but not necessarily because they HAVE
> TO.
>
> Consider a regional or local ISP providing BGP to a customer. The
> customer also has a connection to a "Tier 1". The customer may start
> asking questions when they notice they get 250k routes from one provider
> and only 50k to 80k less routes from you.
It is all in the education. Educated right, you could claim that you're
providing a superior service by _filtering_ what announcements you accept.
better yet, you can claim that you're saving the customer money - THEY don't
have to invest in more RAM / larger routers / larger TCAMs.
OR, money dynamics will be that you charge a higher price for customers that
want a 'full feed' with the higher price based on the higher price you have to
pay to run a default-free network.
the reality is that for many end customers (even multi-homed ones), receiving a
'default' route from an upstream rather than a ton of more-specific routes is
perfectly acceptable. they can filter out that 0/0 if they don't want it,
otherwise "things still work" if they accept it.
in short: it is a MYTH that folks THINK they NEED a full routing table. most
folks don't.
cheers,
lincoln.
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