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