IP Metrics' NIC Express edged out the competition. This product supports switch-independent incoming load-balancing and offers an informative user interface and excellent fault tolerance. IP Metrics also sells a separate product, NIC Express Enterprise Manager, to manage and keep status tabs on all NIC Express servers running on the network. Time-limited demos of NIC Express and Enterprise Manager are available at IP Metrics' Web site. IP Metrics is the only vendor to offer central management across multiple servers. Unfortunately, NIC Express runs only under Windows NT 4.0 and Windows 2000, though IP Metrics officials say the company is working on a Linux port.
NIC Express was able to keep up in performance with the software supplied by the hardware manufacturers. It didn't beat 3Com's or Adaptec's solutions in the download test, and 3Com's EtherLink led in the upload test as well. However, NIC Express scored highest in the bidirectional test, and it also used a bit less CPU power than Intel's solution.
Another of NIC Express' strengths is that it can do fault tolerance and load-balancing across multiple vendors' products and speeds. For example, if you have machine with a Fast Ethernet Intel card and a 10-Mbps built-in 3Com card, NIC Express can be set up so that if the Fast Ethernet link goes down, the system can fall back on the Ethernet card. The same is true of a fiber and copper connection -- as long as your connections are Ethernet, you'll be fine.
NIC Express' real-time statistics display is better than that of any other product we tested. By opening up the status screen, you can see and group data based on what percentage of data is IP, IPX, AppleTalk or NetBEUI. You can also see how effective the load-balancing is by viewing how much data is being uploaded or downloaded from each adapter.
The fault-tolerance capabilities of NIC Express exceed those of the other products as well. Traditionally, faults are detected by listening for link-down interrupts sent by a network card. However, NIC Express can work at Layer 3 of the IP stack. Periodically, each card will ping the others in the group. If the cards can't communicate with each other, the software assumes there's a break in the network beyond the switch to which the card is connected. For example, an administrator may have connected each card to a separate switch for added resiliency. If the uplink connection on one of those switches dies, software that relies only on link-down interrupts won't be able to detect the break and will send traffic into limbo. Or, if one of the adapters is placed in a different VLAN (virtual LAN), that would block some intercard traffic. If, for whatever reason, your environment does not support this capability -- perhaps a firewall that blocks ping between cards, for example -- NIC Express offers the option to use only the traditional link-down interrupt.
But the software's best feature is its ability to see which adapters have recently failed. In the status screen, an adapter is assigned one of five possible icons: working normally, stopped for the first time, working but failed before, stopped and has failed before, and failed so often it has been pulled from the group. If an adapter fails a certain number of times per hour (the default is three, but this is user settable), the adapter is considered faulty and is not reactivated, thus stopping a broken card or link from constantly failing over. If you do not like this feature or are testing out failover capabilities, it can be turned off. If the failure level is set to 15 times an hour and a card fails an average of once every four minutes, then there is definitely a problem, and you'll know it. None of the other vendors offers this status-tracking capability -- their offerings will just keep on doing fail-restore, fail-restore ad infinitum. Furthermore, detected events are sent to the NT Event Manager as well as to an SNMP message. You can also use NIC Express Enterprise Manager for central management across multiple servers.
NIC Express for NT version 2.02, NIC Express for Windows 2000 version 2.12, $349 for Ethernet; $695 for token ring. Available: Now. IP Metrics Software, (817) 358-1007; fax (817) 358-1026. www.ipmetrics.com
3Com Corp. EtherLink Server 10/100 PCI NIC, version 3C982-TXM, with DynamicAccess
3Com racked up very high benchmark numbers, with the best bidirectional scores out of all the hardware vendors (IP Metrics' software product was superior, however). Although 3Com has NIC drivers for virtually every OS, including Sun Microsystems Solaris and SCO Unix, load-balancing software is limited to Windows NT, Windows 2000 and NetWare. Linux NIC drivers are available on 3Com's Web site but are not officially supported. IP Metrics' and 3Com's products were neck and neck in performance, blowing the other vendors out of the water, but we ranked the EtherLink second because its fault tolerance was not as robust as that of NIC Express.
A dual-port card, the EtherLink required only two PCI slots in our test bed. This is a good setup because if one card dies, you still have two ports to carry the load. Slot space is sometimes very tight in servers. If your server has four slots, for example, it's possible that most of them will be used up by disk controller cards or SSL (Secure Sockets Layer) accelerators. A dual-port card offers a solid compromise between slot space and fault tolerance.
3Com's DynamicAccess management technology requires a second IP address for incoming load-balancing. The server doesn't normally advertise or respond to pings from this second address; instead, it tells a machine connecting to redirect to the new IP address during the TCP setup. Aside from that, the main point of contact with the server is with the primary NIC. This setup worked well in our test bed, though we did get lower throughput during the bidirectional test than in the download test. The EtherLink's failover capabilities were similar to those of Intel's and Adaptec's cards, using the NIC's line-down interrupt.
3Com EtherLink Server Dual Port 10/100 PCI with DynamicAccess, version 3C982-TXM, $299 list, $248 at 3Com's Web site. Available: Now. 3Com Corp., (800) 638-3466, (408) 326-5000; fax (408) 326-5001. www.3com.com
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