Where is the edge of the Internet? Re: no ip forged-source-address

Matt Buford matt at overloaded.net
Tue Nov 5 01:47:46 UTC 2002

On Mon, 4 Nov 2002 sean at donelan.com wrote:
> The only equipment I'm heard here which has serious issues related to
> feature availability is the 12000 (which was never a particularly good
> aggregation device to begin with). RPF works fine on 7200, 7500, and
> 6500, from my experience. I've not used 12000's for customer aggregation
> since they historically haven't been designed for or adequate in that
> respect.
> As such, I can understand providers not being able to apply RPF
> on 12000's, at least unless they are acquiring E3 cards for new installs.

6500s can do it, but enabling it doubles the size of the FIB, and the FIB
can only hold 244,000 unicast entries.  So, with RPF enabled on any
interface, your limit is now 122,000 routes.  With a full BGP view, you're
probably dangerously close to this number.

You're supposed to be able to exceed that number and simply end up with some
networks being software switched, however, I've seen a number of 6509s
running native software either fall over or experience serious bugs (not
fixed as of 12.1(13)E) when exceeding this limit.

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