Channel partners are uniquely qualified to guide customers through the upgrade process, but they must keep up to date. The technology is new and constantly evolving. Not all standards for 10 gigabit Ethernet (GbE) are stable. Partners must remain in touch with vendors and track vendor timetables to understand limitations in current product versions and the status of updates.
Consolidated data centers require increased data rates
Eliminating individual servers with virtual servers executing on a single higher-power server reduces equipment costs, power usage and administrative expense. Combining processing on a single server means combining the data traffic. While a 1 gigabit Ethernet link may have been sufficient for each server prior to consolidation, it is unlikely to be capable of supporting multiple virtual servers.
Reducing data center interconnect costs
Configuring one or a small number of 10 GbE links is clearly more cost-effective than a larger number of 1 GbE links. However, the benefits of 10 GbE extend beyond simply reducing the number of server and switch
In the past, the throughput rates required to connect servers to storage area networks (SANs) and network-attached storage (NAS) have exceeded Ethernet capacity. As a result, these connections have utilized Fibre Channel or InfiniBand. The increase in throughput to 10 gigabits makes Ethernet competitive for server-to-storage connections.
Replacing separate switches for the network and for storage with a single 10 GbE switch will reduce equipment cost and power usage, but channel partners should exercise caution before urging customers to move quickly to make this change.
Simply increasing Ethernet to 10 gigabits is not sufficient to replace existing technologies. Storage interconnects cannot tolerate packet loss, but traditional Ethernet does not guarantee that packets will not be lost. Higher-layer protocols such as TCP detect and retransmit in the event of packet loss, but the time delay required is unacceptable for adequate storage performance.
The IEEE has developed a series of new protocols to address this problem. Successive revisions of these standards have been issued, but none has reached final ratification. All of the major switch vendors have developed implementations of these protocols, but tests at the University of New Hampshire Interoperability Lab earlier this year revealed incompatibilities among vendor implementations.
Inter-vendor compatibility cannot be expected until protocols are finalized and further rounds of tests completed. Customers who currently rely on a single vendor can proceed but should remember that not all vendor-announced capabilities are actually available in currently shipping products.
Proceed with caution. Storage throughput and latency are critical. Establish a baseline before introducing new interfaces and switches. Compare the baseline against measured performance after each change, and be prepared to work with equipment vendors if problems occur.
Server interfaces continue to evolve
Server interface technology is an additional area where channel partners should monitor vendor plans. Integrating the network interface onto the server motherboard reduces the overall solution cost. Motherboard interfaces for each successive Ethernet generation have become available soon after the technology matured.
A possible mismatch is looming between the product plans of interface chip vendors and switch vendors. The major chip vendors have announced interfaces for 10GBase-T, the 10 GbE twisted-pair standard, while switch vendors are promoting SFP+ owing to its low cost, reduced latency and power requirements compared with 10GBase-T. SFP+ limits interconnect distance to 10 meters, which is more than sufficient to connect the server to a top-of-rack switch, according to Dave Passmore, research director at the Burton Group. Passmore has observed that some customers are finding it difficult to plan, but the situation may change when the first 10GBase-T LAN on motherboard products ship in late 2010 or early 2011.
Data center update requires changes in management software and practices
Combining network and storage interconnects in a single set of switches requires changes in both management software and practices. What had been two separate sets of tasks assigned to distinct individuals now merges. The change requires staff members to add new areas of expertise as well as learn the mechanics of new software packages.
Partners should be aware of potential pushback from data and network center staffs. Combining functions may be seen as a threat by some individuals. Staff issues can undermine a project as effectively as technical problems. Partners should work with management to anticipate these types of problems early in the project.
Despite potential difficulties, channel partners should not hesitate to recommend that customers utilize 10 GbE technology. Though still evolving, the new interfaces, switches and protocols offer significant opportunities for performance increases and cost reduction.
David B. Jacobs of The Jacobs Group has more than 20 years of networking industry experience. He has managed leading-edge software development projects and consulted to Fortune 500 companies as well as software startups.
This was first published in September 2009