nanog mailing list archives

Re: Software router state of the art


From: Florian Weimer <fw () deneb enyo de>
Date: Mon, 28 Jul 2008 22:42:08 +0200

* Joe Greco:

I'm not sure where the claims about "{one, few} flow{s}" are coming from.
Certainly the number of flows on a typical UNIX box acting as a router is
not that relevant unless you specifically configure something like 
stateful firewalling, because the typical UNIX box simply doesn't have a
*concept* of "flows."  It deals with packets.

You are mistaken.  Linux routing is flow-based.  Ever wondered what
those "dst cache overflow" messages mean you see during a DoS attack?
It's the flow cache complaining that it can't expire records in an
organic manner.

I don't know much about FreeBSD.  I think it got a route cache after
FreeBSD 4, too.  That's the reason why the FreeBSD 4 IP stack is still
so popular.


Current thread: