Network Card with a Brain
New Etherlink card saves CPU cycles.
If you’ve been around the PC business
for a few years, you may recall the revolution in graphics
cards that happened when the first accelerated graphics cards
were introduced. Recognizing that displaying complex graphics
was a computation-intensive process that didn’t interact
much with other parts of modern software, these cards included
their own microprocessors to take over part of the load from
the CPU. The success of this approach can be measured by noting
that it’s hard to buy a system without such a graphics
card today. Now, 3Com (in partnership with Microsoft) is trying
to do the same for network operations.
The first fruit of this partnership is
the 3CR990 family of network cards, with an integrated processor
that 3Com has dubbed the 3XP. For this review I worked with
the 10/100 PCI 10BaseT version of the card on a Win2K system.
Indeed, if you’re not running Win2K, you probably don’t
want to spend the money on this card. That’s because
it’s designed to work with new APIs in that operating
system that allow the CPU to offload two critical networking
operations: TCP segmentation and IPSec.
TCP segmentation is a process that goes
on whenever a computer wants to send a large data block over
TCP/IP. Because Ethernet frames are limited to 1513 bytes,
large blocks must be broken up into multiple smaller frames,
each with its own header information. The 3CR990 allows the
CPU to send the entire block of data to the network card,
and then the network card itself handles the segmentation
of the data into frames.
IPSec is a standard for TCP/IP security
supported by Win2K that encrypts data sent over the network
with 168-bit DES. While Win2K can accomplish this entirely
within the operating system, it can take a lot of CPU cycles
to do so. The 3CR990 implements the DES algorithm in its own
firmware, allowing the CPU to just send the data and handling
the encryption and decryption on the network card itself.
3Com says that this can lower the CPU load for IPSec by 33
percent. Because the card implements this strong algorithm,
it can’t be exported outside the U.S.A. and Canada (there’s
also a 56-bit version that is export-legal).
The card installed easily in my test system,
although it required installing drivers after the operating
system was installed (this may be because I was using a late
beta version of Win2K) rather than as part of the hardware-detection
process. Once installed, that was it: no problems whatsoever.
Turning on IPSec is as simple as choosing one option in TCP/IP
properties, and the card communicates fine with everything
else on my network, encrypted or otherwise. At a street price
of about $100, this card is worth a serious look by anyone
planning a new Win2K-based network who’s concerned about
Mike Gunderloy, MCSE, MCSD, MCDBA, is a former MCP columnist and the author of numerous development books.