Re: Ping flooding (fwd)

[Per Gregers Bilse <bilse () EU net>]

On Jul 9, 17:57, "Daniel W. McRobb" <dwm () ans net> wrote:
> The sampling Curtis mentioned on the NSS routers is a bit different.
> For one, it doesn't really impact forwarding performance (and hopefully,
> if/when implemented on the Bay, will not impact forwarding performance).

Not to pick nits, but what I quoted was a cache snapshot; caches
don't impact performance under normal circumstances, though their
construction may do so.

> But what we're specifically looking for in terms of continuous sampling
> (such as that we do on the NSS routers) is a net matrix... if you
> changed the Cisco flow switching stuff to use network numbers (and
> mask), you'd have something very much like what we're looking for in
> terms of continuous sampling.  From there we build AS matrices, etc.

Yes ... but you shouldn't need anything special for that.  We have
been doing the same for a long time, using regular IP accounting on
the edge routers, which is then summarised over a full routing table.
The only discrepancies that occur are if changes in routing occur
between the time of accounting and processing, but this tends not to
be a problem.

> The other thing about the flow-switching data that's different than the
> NSS (and probably what we'll get from Bay) is that there aren't really
> any nice ways of retrieving/storing the data automatically.

This used to be true, but "probably" isn't true any longer.

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