We've been here before. When Gigabit Ethernet arrived in the late 1990s, network managers could take the order of magnitude leap to true Gigabit or create "fractional" Gigabit links by using multi-port Fast Ethernet and "bonding" software. Now, with 10Gig Ethernet becoming common on LAN switches, a similar choice awaits us. And it's the same - except that it's different.

The part that is the same, naturally, centres on cost. With 10Gig Ethernet, as with any new technology, initial costs are high. It's not until volumes increase that prices tend to drop.

With 10Gig, market forces have already seen per-port switch prices plummet from the US$25,000 range to a mere $13,000 today - but that's still pricey. Knowing that, vendors are typically targeting high-end clustering and data centre applications where speed is the need and price is not an issue.

Network interface cards (NIC) aren't cheap, either. One of the few general-purpose 10Gig Ethernet NICs I could find was the Intel Pro/10G Ethernet LR Server Adapter. One site will get you this for 'only' about $3,500. That's for one, not a 20-pack. Did I mention that it's pricey?

Let's also not forget that, currently at least, all 10Gig Ethernet is optical, not copper. Even in the Gigabit world, fibre-optic connections are more costly than copper.

Now let's look at current Gigabit pricing. I'll grant that when one compares a 24-port Dell or a 3Com fixed-port switch to some high-end datacentre beast, it's not a true apples-to-apples comparison. But it is a valid comparison in the sense that it provides wire-speed Gigabit connectivity to your servers and endstations.

While the 'sale ends soon,' as I write this piece, a humble, unmanaged PowerConnect 2624 offering 24 Gigabit ports can be bought for $299, or about $12.50 per port. Given that the current price for a 10Gig port is about a thousand times greater, you definitely have something to think about there. It might be time to 'go fractional'.

From Intel, for example, you can buy a Pro/1000 MT Quad Port Server Adapter. You get four Gigabit copper ports for roughly $450. In theory then, for less than $500 - including the four switch ports you'd eat up - you'd get 400Mb/sec, that is 40 percent of the bandwidth, for about 3 percent of the cost of a 10Gig Ethernet link.

Now there are complications with dealing with multi-port NICs. You need to grapple with teaming software to make them act as one. You might require special switching capabilities such as Link Aggregation (which, by the way, our $12.50 per port switch supports). But my point is that with such a jaw-dropping price difference it's worth considering whether fractional 10Gig Ethernet can do the job for you.

Let's not forget what's different, too. With the rise of 10Gig, we are hearing serious discussion about things like IP storage and clustering. To help us reach those goals, we have vendors such as Ammasso and S2IO that are building specialised NICs that implement advanced features such as Remote Direct Memory Access or TCP/IP Offload. While they cost more, they do more.

So look to use 10Gig Ethernet and specialised NICs for the jobs that both are targeted for - but don't overlook the potential benefits of fractional 10Gig Ethernet that you can enjoy today.

Kevin Tolly is president of The Tolly Group, a strategic consulting and independent testing company in Florida. He can be reached as [email protected]