Aggregation & path information [was: 200K prefixes - Weekly Routing Table Report]
Patrick W. Gilmore
patrick at ianai.net
Fri Oct 13 19:14:38 UTC 2006
On Oct 13, 2006, at 3:04 PM, Philip Smith wrote:
> I was kinda hoping that it would hit 200K on Tuesday, then I could
> added the announcement to my aggregation recommendations lightning
> ;-) Bit sad that a 200K table can be aggregated down to 109k prefixes
> with no loss of path information (in my BGP table view).
I find this interesting.
Obviously the table contains kruft. But I know we could not shrink
it to 109K prefixes without losing something from where I sit. Are
you sure there's no additional path info?
If there were a way to guarantee certain prefixes are completely
superfluous, we could make a hit list of just those providers, then
ridicule or filter or cause them pain in some way to make them stop
causing us pain. I haven't seen that type of report posted publicly,
just "this CIDR can fit in that one" without actual guarantees that
_paths_ are equivalent. (Usually the origin AS is matched as well as
the prefixes, but that's not the same as guaranteeing the path is
Of course, this is non-trivial. But then neither is aggregating the
global table. :)
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