Software router state of the art

William Herrin herrin-nanog at
Wed Jul 23 16:07:23 UTC 2008

On Wed, Jul 23, 2008 at 11:24 AM,  <Valdis.Kletnieks at> wrote:
> 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.

The Endace DAG cards claim they can move 7 gbps over a PCI-X bus from
the NIC to main DRAM. They claim a full 10gbps on a PCIE bus.

Bill Herrin

William D. Herrin ................ herrin at bill at
3005 Crane Dr. ...................... Web: <>
Falls Church, VA 22042-3004

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