[TriLUG] OT: what is a gigabit ethernet server?

[David A. Cafaro]

Just as a reference on Device/Bus speeds and bandwidth I found this
website: http://www.acme.com/build_a_pc/bandwidth.html

A quick look over at it appears to be accurate.  

-David

On Thu, 2004-12-09 at 10:55, Aaron S. Joyner wrote:
> Brian Henning wrote:
> 
> > ----- Original Message ----- From: "Christopher L Merrill" 
> > <chris at webperformanceinc.com>
> >
> >>
> >> "Gigabit Ethernet: This term does not connote an actual operating speed
> >> of 1GB/sec. For high-speed transmission, connection to a Gigabit 
> >> Ethernet
> >> server and network infrastructure is required."
> >>
> >> What does that mean?  Does that mean I need something besides a switch
> >> with a gigabit port?
> >
> > I think the description was trying to explain the maxim that a chain 
> > is only as strong as its weakest link...  There are plenty of 
> > consumers (/idiots) out there that would not immediately grasp why 
> > they only get 10Mbit through their 10Mbit hub to their 10Mbit server 
> > when their workstation has 1Gbit. Dell's just trying (vainly, 
> > probably) to point out that you'll only get gigabit performance if all 
> > the steps along the way are gigabit.
> >
> > Cheers,
> > ~B
> >
> Brian does a good job of pointing out the actual purpose of Dell's 
> statement, but there's a greater subtlety that bears mentioning.  If you 
> use cheap hubs, and regular PCI Gigabit NICs, you won't see 1,000 Mbits 
> / second.  In order to get up into that range, you're going to need to 
> overcome two bottlenecks.
> 
> First the PCI bus can't really handle that much throughput, so you're 
> going to need to use something like Intel's CSA architecture (which ties 
> the Gig-E controller into the north bridge chipset, bypassing the PCI 
> bus), or go straight to PCI-X, preferably on a well-designed motherboard 
> using AMD's HyperTransport.
> 
> Second, you'll also need to up the MTU of the interface and use what are 
> commonly referred to as "Jumbo Frames", meaning that you send data in 
> packets larger than the standard 1500 byte chunks.  The maximum 
> practical MTU for Gig-E is usually 9000 bytes, but take note that most 
> inexpensive Gig-E switches won't support the larger frame sizes (and 
> will drop or truncate those packets).
> 
> Hopefully this will help someone who's looking into Gig-E understand how 
> to set their expectations accordingly.  :)
> 
> Aaron S. Joyner
-- 
David A. Cafaro
dac(at)cafaro.net
Admin to User: "You did what!?!?!"