Re: [Ebtables-user] Can someone suggest good hardware to use?

[Matthew N. <mat...@sn...>]

Hi David,

I don't pretend to know everything about performance, but we have had to
do performance tuning on our products because we use comparatively low
end embedded CPU's (ie SH4 240MHz).  Find my comments and some
experience included.

> I am trying to spec some hardware to handle filtering of alot of data.
> 
> 
> The intendted system would bridge 2 gigabit ethernet interfaces, and be
> capable of filtering without packet loss bi-directional udp traffic of
> about 100,000 packets per second each way with an average packet size of
> 72 bytes.
> 
I don't know much about this really high end of town, but that is a
*lot* of packets!!  Handling 200,000 packets/sec might be beyond any
machine.  I wouldn't be surprised if you need a specialised ASIC for
this task.  Of course I wouldn't be surprised if a high end P4 could do
it as well, so don't lose hope.

> I have done some experimentation with a PIII500 system with 2 realtek
> 100bT FD cards, and the limiting factor here seems to be the CPU.
> Obviously this is just an experimental system not intended to take full
> load, but it peaks at about 6,000 packet/sec with 100% CPU.
> 
Is you card using a RTL8139A/B/C/D?  They are not good choices for
performance applications.  They pull in packets unalligned, and are
slow.  You are much better off with an Intel card, one of the expensive
3COM cards, or the cheap, but hard to find, RTL8139C+ (note the + it is
very important).  I doubt you will be able to find a 8139C+ FD.

Is this figure uni-directional (i.e. total number of packets
processed)?  We can do ~8000 1500 byte packets/sec using a 240MHz SH4
CPU and Realtek 8139C+ with a full firewall and running as a bridge.  I
would expect given the size of the L2 cache on the PIII you should be
able to approximately double that rate.  I am not really comparing
apples because I used TCPblast to come up with those figures on a copper
network.  Hopefully it gives you an idea though.

Also your firewall rules can have a significant affect on the speed of
traffic.

Don't forget L1/L2 cache size.  My experience has shown that this has a
big impact on packet throughput.

> Does ebtables work with the fast switching driver for tulip cards? Is
> there a particular chipset for 1000bT that has an optimal driver? 
> 
I have heard good things about the Intel Gigabit Ethernet adapters, but
have no personal experience with them.

> Does someone have a setup handling similar amounts of traffic?
Our CPU's tend to have much lower speeds, so we would never reach such
packet throughputs, but with a high end P4/XEON you may be able to hit
these numbers

Cheers

Matt
-- 
Matthew Natalier, Systems Programmer, SnapGear, Inc.
Ph: +61 7 3435 2805, Fx: +61 7 3891 3630
Email: mat...@sn..., Web: http://www.SnapGear.com