Please Check Filters - BOGON Filtering IP Space

Joel Aelwyn lucifer at
Fri Jan 21 19:26:57 UTC 2005

On Fri, Jan 21, 2005 at 09:01:13AM +0200, Hank Nussbacher wrote:
> On Thu, 20 Jan 2005, James Laszko wrote:
> > Well, if the router CAN run BGP, the feed from Cymru is only about 84
> > prefixes - not a lot of memory tied up there, is there?
> I am *not* talking about the leaf - rather the core.  I am curious what
> resources are needed to manage 200K BGP peers other than 200K IP
> addresses.  Is there an IOS limit on the number of BGP peers?  Memory?
> -Hank

I can't comment on that, but it strikes me that it might be a fairly
non-optimal solution, for the simple reason that we're talking about a
small, low-delta, highly-distributed feed where session state is going
to eat most of your CPU and memory, but any *one* session is unlikely to
really need much except keepalives. And, of course, no need to actually
route anything.

Sounds like an excellent thing to throw commodity (OK, probably rackmount,
but still) PC hardware at (potentially in clusters, I haven't looked into
what the memory/CPU load of sessions boil down to on recent versions of
BGP-capable software that runs on such).
Joel Aelwyn                          System Administrator -
lucifer at    
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