Dell Bets On iSCSI For Networking ConvergenceDell Bets On iSCSI For Networking Convergence

Dell is promoting converged networking based on iSCSI with the servers that it sells through what it calls a simpler, more standards based approach than its server rivals.

In a recent interview, Praveen Asthana, VP of enterprise storage and networking at Dell's Round Rock, Texas, headquarters, illustrated how Dell competes with HP's BladeSystem Matrix and Cisco Systems Unified Computing Solutions, which both now offer converged networking tying blades into the nearby network fabric.

Converged networking, where I/O traffic is moved off the server, sometimes at 10 Gb Ethernet speeds, into the network fabric, is considered an asset in settings where the servers are being loaded with virtual machines. Each virtual machine often generates its own I/O needs. By allowing the server to deal with both networking and storage traffic in the same manner, converged networking reduces the computing workload on the server, offloading it to the adjacent network devices.

Virtualized servers not only make an increasing share of the data center, they're also frequently the basis for public and private cloud computing, such as Amazon Web Services' EC2. In the future, x86 servers are expected to run dozens of virtual machines per server, provided they're equipped with the I/O handling capabilities to support the increasing load. So Dell's distinct, iSCSI approach to converged networking is likely to be put to the test sooner rather than later.

Cisco has adopted its own approach to converged networking via Fibre Channel over the Ethernet at 10 Gb speeds, which it calls Data Center Ethernet or DCE, making use of Fibre Channel devices.

Critics point out that DCE is an implementation of FCoE unique to Cisco and buying Cisco servers commits the buyers to Cisco's way of networking. Cisco has responded that it has submitted DCE to the IEEE standards body and a working group has been commissioned to move it toward becoming an industry standard.

Dell says, whatever the merits of FCoE, it's found that iSCSI, a storage networking protocol that's been adapted to work over the Internet Protocol, serves as a satisfactory basis for implementing converged networking over 1 Gb Ethernet broadly used in corporate networking and data centers and 10 Gb Ethernet, the upgrade waiting in the wings.

Furthermore, Asthana says, iSCSI will continue to be the right standard as Ethernet moves up to 40 Gb per second and 100 Gb per second speeds. In short, iSCSI is a standard that's proven good enough for today's needs at 1 Gb speeds and will remain good enough far into the future. Other server vendors can try to convert the world to using Fibre Channel over Ethernet, a step that would require follow up investment in adapters and switches, Asthana continued. "iSCSI has been tried and tested over 15 years. Why not talk Ethernet over Ethernet," he asked Jan. 12 in a face-to-face meeting with a team of information editors. Doing so results in a network implementation that is "75% cheaper" in buying switches and host bus adapters connecting the server to the network.

Dell's implementation of converged networking relies on the DCB ,or the IEEE's existing Data Center Bridging standard. In addition to Cisco's DCE, there's another variation in the works, CEE or Converged Enhanced Ethernet, sponsored by Juniper Networks, IBM and other vendors. Asthana says Dell is sticking to the established standards, DCB and iSCSI. iSCSI was established as a standard by the IETF in 2003.

There's a major advantage in doing so, he says, that makes iSCSI modern again, despite the competing standards in the works. The roots of Fibre Channel networking lie in a hardwired approach to the storage network, which was assumed to be set up once for life.

Moving a virtual machine from one physical server to another, as in VMware's VMotion function, means the VM's storage connection over Fibre Channel will have to be remapped, probably by a storage administrator. With iSCSI, the remapping can occur automatically as the VM is moved because iSCSI matches up logically with the Internet Protocol, Asthana said.

As proof, Asthana said VMware develops its networking and storage components on an iSCSI based storage system so the mapping and remapping can occur automatically. "VMware develops its stuff on an EqualLogic storage system," he noted, and Dell acquired EqualLogic in 2008 for $1.4 billion, incorporating EqualLogic products into the storage systems that it sells.

"We've been banging the drum for iSCSI and DCB for three years," said Matt Baker, Dell's enterprise strategist for storage and networking in a separate interview. "They're not only good for virtualization, they're good for quality of service and other management issues," he added.

Dell has made its bet on where the future of network convergence will go because iSCSI and DCB "achieve those converged goals, even with today's 1 Gb Ethernet," he said.