Scalability of ALTQ

Bernhard Schmidt berni at
Wed Jan 12 13:01:36 PST 2005

Hi Max,

> Generally speaking, 30-40Mbps are no problem.  The limiting factor for pf 
> (as for any packet filter/firewall/etc.) is packets per second (pps).
> In the end there is no alternative to just try it.  In the worst case
> scenario (with 64 byte per packet) this means about 625 kpps, which
> will certainly overload most systems.  An *average* packet size of
> 400-800 byte/packet, however, resulting in 50-100 kpps, should already
> be doable without problems.

I just had a short look, on the busiest encapsulator we're doing 10 kpps
at 40Mbps currently, I don't think it should rise up much more. 

> From a very first glance, I think HSFC is what best suits your application.
> Here again, you must make sure not to overload your parent with the
> client bandwidth.

Hrm, I guess I'll just convert a current Packeteer policy to an pf one
and have a look whether it loads smoothly. I heard today that we already
have a Dell PE750 on stock, I think I'll give it a shot. In the end,
a mirrored switchport to the BSD box should be sufficient to test.

Thanks for your answers

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