Software router state of the art

Valdis.Kletnieks at Valdis.Kletnieks at
Wed Jul 23 15:24:19 UTC 2008

On Wed, 23 Jul 2008 02:52:56 PDT, Zed Usser said:
> There's been some discussion on the list regarding software routers

The performance of "software routers" has always had a hardware component.

Basically, for the vast majority of them, take your PCI bus bandwidth,
count how many times a packet has to cross it, and do the math.  You can't
forward more than that much traffic no matter *what* software you run on
that box.  If that number falls short, stop right there and look for
some box of different design that has the required backplane bandwidth.

You will, of course, take additional performance hits due to locking issues
and similar in your software stack (that, and most "software" routers will
suffer from not having special hardware assist for routing table lookups).

Let us know if you find a suitable chassis/motherboard that has enough
bandwidth to make it worth thinking about for anything other than the
smaller edge routers that most providers have zillions of... :)

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