[j-nsp] hardware lookup OT

Richard A Steenbergen ras at e-gerbil.net
Mon May 19 15:16:51 EDT 2003


On Mon, May 19, 2003 at 08:07:45PM +0200, Piotr Marecki wrote:
> I suppose cisco implementation is also hw specific (for example on 1000x
> esr "show hardware pxf cpu cef" gives "Shadow 12-8-4-4-4 Toaster Mtrie".
> Also . it's kind funny that ( in my experience ) Cisco wasn't able to
> provide decent and fast gear for ISP ( let command "show pxf crash" be
> an example ... ) in last years given ( i think so  ) lot's of more cash
> for R&D .

For pxf perhaps, but most older stuff is implemented with general purpose
processors... A simple 256-way mtrie is like 40 lines of code tops.

Obviously if you want 40Mpps, you're going to be desigining custom ASICs.  
If you want decent performance on cheap hardware (7206-like performance),
the mtrie on a general purpose CPU is still the simplest way to go.
Cisco's CEF problems usually relate to dCEF.

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
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