[84631] in North American Network Operators' Group
Re: PBR needing to hit the cpu?
daemon@ATHENA.MIT.EDU (Fergie (Paul Ferguson))
Sun Sep 18 16:51:37 2005
From: "Fergie (Paul Ferguson)" <fergdawg@netzero.net>
Date: Sun, 18 Sep 2005 20:50:05 GMT
To: tony.li@tony.li
Cc: nanog@merit.edu
Errors-To: owner-nanog@merit.edu
What I think we're talking about here is not really "policy-
based routing" but "policy-based forwarding", right?
If so, then any nin-FIFO scheme would have to to be kicked up
to the CPU, right?
- ferg
ps. I heard you left Cisco again. ;-)
-- Tony Li <tony.li@tony.li> wrote:
On Sep 17, 2005, at 8:57 PM, David Hubbard wrote:
> Just curious, do most vendors' hardware need to hit the
> cpu when doing policy-based routing? I found one of my
> border routers' cpu's on the bad end of a DDoS but once
> I turned off a not necessarily required setup to force
> some outbound traffic to take a specific outbound link
> via PBR, the DDoS traffic was no longer an issue. It was
> only about 200 Mbit so I hadn't expected it to be an issue
> but apparently it was; I was surprised when support told
> me the PBR was making traffic hit the cpu.
That's not at all surprising. PBR would be pretty hard to push into
a hardware forwarding path.
Not impossible, but certainly challenging.
Tony
