Re: [vox-tech] What's the real deal with network cards

[Peter Jay Salzman <pMAPS@dirac.org>]

let me add to what bill said.

some cards have data alignment restrictions, meaning that they can't send or
receive data until a send or receive buffer is filled.  these cards have
extra overhead in copying data from the wire to a buffer (or from a buffer
to the wire).

i had a conversation with don becker[*] about this, and he explained the
details (most of which was over my head).

anyway, one class of cards which have this stringent data alignment issue
are the cards based on the rtl8129.

i have to point out that when i had this conversation, the 8129 and 8139
shared a driver.  now they dont.  i'm not sure if the 8139 cards have the
same issue.

in any event, don's[**] conclusion was that you won't really see a
performance issue unless you have a bunch of systems which are running
parallel code, where you're depending on getting ultra fast replies from
peers working on parts of your calculation.

pete

[*] i'm not nearly as bad about name dropping as some, but allow me to have
my 15 minutes of fame!  ;-)

[**] no, we're really not on a first name basis.  i'm just name dropping
again.

On Wed 28 Feb 01,  8:09 PM, Bill Broadley said: 
> AFAIK as 100 mbit or less it maters very little for the hardware.  Quality of
> the drivers can make a big difference though.
> 
> 3com has some cards that have hardware checksumming which is nice but not
> really a big deal.  Not sure which other cards have this feature.
> 
> At Gigabit the legacy ethernet/tcpip stack is ummm suboptimal, so the design
> of the card can make a BIG difference, but just about any 10/100 mbit
> card should be just fine, even for a server.
> 
> I've seen just bout anything come within a few percent of optimal, i.e.
> saturating the network, even crappy $10 ISA ne2000 clones.  Keep in
> mind I'm refering to linux, I've seen windows often get less then 10%
> utilization, especially over window fileshares.
> 
> Personally my favorite is the netgear cards that you can get a box of
> 10 for under $200 ish.  Use the tulip driver which has been good/stable
> for years.
> 
> So as a rule of thumb, unless it's gigabit it doesn't matter.  
> 
> On Wed, Feb 28, 2001 at 09:40:33PM -0600, Jay Strauss wrote:
> > I was just at Microcenter picking up network cards.  Cards with the rtl8139
> > chip ranged from
> > $9.75 (the ones I bought) to about $35.  Is there any difference?  Then
> > there where cards (linksys)
> > that used the tulip driver that ran from 25 - 45.  Then there are other
> > cards 3com, Intel, etc.. I don't know what chip and/or driver they use.
> > 
> > Is there noticeable difference between the chips/drivers, in speed,
> > compatibility, dependability?
> > 
> > Jay Strauss
> > Database Architect
> > jjstrauss@yahoo.com
> > 
> > 
> > _________________________________________________________
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> > Get your free @yahoo.com address at http://mail.yahoo.com

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