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Date:      Sat, 16 Oct 1999 10:35:34 -0700
From:      Mike Smith <mike@smith.net.au>
To:        "Jimbo Bahooli" <griffin@blackprojects.org>
Cc:        freebsd-hackers@freebsd.org
Subject:   Re: Balancing Outgoing traffic over 2 nics, and nic limitations. 
Message-ID:  <199910161735.KAA06493@dingo.cdrom.com>
In-Reply-To: Your message of "Sat, 16 Oct 1999 02:51:37 CDT." <199910160251370480.0B9DA297@207.109.8.249> 

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> Hello my FreeBSD friends.
> 
> I have two issues.
> 
> The first is how to balance outbound traffic over 2 nics that are on
> the same subnet.  Example configuration:
>
> fxp0: 12.2.2.5 netmask 255.255.255.0
> fxp1: 12.2.2.6 netmask 255.255.255.255
> 
> router at: 12.2.2.1


You can't do this.  If all of the outbound traffic is headed for the 
same router, put two cards in the router and use two separate nets.
 
> Currently I have the obvious static route to 12.2.2.1, which locks onto
> fxp0 so all outbound traffic flows out over that link.  Inbound traffic
> balances per ip as I would expect.  I hope to find a scalable solution
> as I hope to build a server that will utilize 3 nics.

This is not a sensible course of action.

> This configuration is neccessary because by my estimation I have run
> into a limit on the intel pro 100 netcards of 6,000 packets/second.

These cards do not exhibit such a limit.  You may have run into some 
issues with FreeBSD's ability to handle very large numbers of small 
packets with your particular application mix.

> This limit equates to about 30 to 32 megabit/second of web traffic in
> our situation.  I am wondering if anyone else has noticed this limit?

Not in my recollection.  The fxp driver in recent incarnations limits 
the number of interrupts it generates by restricting them to 
low-resource conditions rather than generating one per packet.  And 
I've personally seen an SMP kernel run tolerably while taking > 100,000 
interrupts per second.

> This limit was hit on 2 very different machines, one with significantly
> less power.  Any feedback on either of these issues would be
> appreciated.

I'd start by eliminating the network adapter and driver; move to an 
up-to-date FreeBSD-stable and substitute a 3C905B or C and determine 
for yourselves whether this is really an issue with the card.

General experience would suggest that you should be able to come close 
to saturating your network with even relatively small datagrams using 
either of these adapters.

You also don't mention whether you're running on a switched network; at 
that sort of traffic level you will definitely want to be using a 
switch that supports full duplex operation.

-- 
\\ Give a man a fish, and you feed him for a day. \\  Mike Smith
\\ Tell him he should learn how to fish himself,  \\  msmith@freebsd.org
\\ and he'll hate you for a lifetime.             \\  msmith@cdrom.com




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