The Next xAN: Page 2 of 4

During this exploration, we've been hearing new terms, as upstarts and incumbent vendors alike try to position for the next xAN. Here's our running list, after four months listening to pitches. You'll see that inventing new acronyms is no easy business. It's simple enough to envision Server Area Networks, for example, but how do you go out and market "SANs" without customers expecting to see racks of RAID arrays?

Here's our running list, after four months listening to pitches:

• Blade Area Network (BAN): Blade servers brought together via high-speed interconnect and switching to create a dynamic, available pool of processing to the enterprise.
• Cluster Area Network (CAN): Networking computing clusters clustered together to increase performance and availability.
• Compute Area Network (CAN): More generic than those above, built from any kind of compute resource, from PCs to servers or even mainframes.
• Database Area Network (DAN): A resource structure built from servers, switching, and storage optimized around the demands of large-scale databases.
• Processor Area Network (PAN): We're not entirely sure what this means, but it's not hard to imagine. Much like compute area network, we would presume.
• Server Area Network (SAN): Like the BAN, but not necessarily based exclusively on the blade server, yet somehow different from today's server clusters.
• System Area Network (SAN): An ambitious term that is general enough to approach meaninglessness.

What's the endpoint? The all-powerful Datacenter Area Network (DAN)? Hard to say, but the enterprise data center is undergoing a top-to-bottom makeover, conceived by many as a unified, addressable resource, without the artificial boundaries imposed by the sheet metal around individual boxes.

These new concepts all relate to improving the utilization and/or performance, via network enhancement, in multiserver and cluster environments. Many enterprise server environments are underused to the tune of 80 to 90 percent, so there's a need to improve that. Many clustered server/computing environments experience application performance degradation caused by latency, throughput, and misuse of CPU for tasks other than processing. Solving these problems, and others, is part of the charter for such xAN initiatives.

These improvements are achieved through a variety of solutions including network interface cards (NICs), I/O controllers, switches, and networking software. The newer solutions take it beyond existing products such as TCP Offload Engines (TOEs), simple Layer 2/3 switches, InfiniBand switches, and proprietary, high-speed interconnect technologies like Myrinet and Quadrics. The common thread for the newer solutions is Ethernet, but with enhancements like Remote Direct Memory Access (RDMA), hardware-assisted protocol acceleration, and intelligence (for example, database-routing decisions enabling optimal use of server resources). (See RDMA Rumbles Along, Cenata Plots 'Transparent' Clusters, Vendors Chip Into IP Storage, and Will Offload Chips Be Uploaded?.)