With the development of 10 Gigabit Ethernet (10gE) and the unveiling of Cisco's new Nexus series of switches, what...
was once considered a mature switch market is now experiencing a new wave of innovation.
Server virtualization and front-end applications that require higher bandwidth are driving vendors to develop and adapt to new technology with next-generation Ethernet technologies.
Cisco's launch of Nexus appears to be a direct response to this trend. Perhaps most striking is the introduction of Virtual Device Contexts (VDCs) in Nexus, which allows network managers to create multiple virtual switches on one physical switch. The new Nexus operating system, NX-OS, also makes IP routing features VRF-aware, allowing administrators to segregate traffic more easily.
Converting physical servers to virtual ones reduces the amount of space required for the data center, but it won't necessarily shrink the amount of network infrastructure in the data center, explained Zeus Kerravala, vice president of the Yankee Group.
"I do think it will cause a wave of upgrades in the data center, but it puts a lot of demands on the network that weren't there before," Kerravala said. "The networks have to be reliable, secure and always available, so while you're reducing physical servers, you're also creating more infrastructure [as the network copes with these increased demands]."
Aside from the updated operating system, Cisco's Nexus also incorporates Fibre Channel and Ethernet interoperability. Analysts are predicting a slow decline in Fibre Channel adoption, however, as 10gE becomes the primary method of networking, not only at the front-end but also in storage networks. That is why Cisco is also touting Nexus's ability to run converged Ethernet, a set of draft standards that would enable all types of network traffic on a single medium.
"I think 10gE will eventually overtake Fibre Channel, but that'll take years," Kerravala said. "For companies that actually have large investments in Fibre Channel, it will take a while to replace that technology [simply because there's a high cost of adoption]."
The trend is similar to adoption of other new data center technologies: Large corporations can afford to make the switch to 10gE and wait for their ROI, while smaller companies wait for the cost of ownership and adoption to go down.
At least one other company has recognized the importance of developing this technology today. Brocade, a leading vendor of storage networking products, introduced its DCX Backbone switch this year. Like Nexus, it features Fibre Channel and Ethernet interoperability. It is also designed to run converged Ethernet. Brocade further demonstrated its recognition of a rising wave of Ethernet switching innovation when it bought Foundry Networks. The deal gave Brocade high-end Ethernet engineering expertise and a mature line of products.
Ethernet was never designed to be lossless, however, and losing packets in the storage network is unacceptable. But according to Dave Passmore, research director at Burton Group, there are two solutions to the problem. The most common approach is to run TCP/IP over the Ethernet. The other is Fibre Channel over Ethernet (FCoE). "The downside is, because you're not running TCP, you're really dependent on the underlying Ethernet infrastructure to be error-free with low latency," Passmore said.
The advantage to using Ethernet in the data center is the establishment of a common network fabric, eliminating the need for separate Fibre Channel SANs and reducing the number of connections per server.
"The idea is that maybe we can collapse all this to a single set of switches with a single Ethernet connection," Passmore said.
That's the idea, but -- according to Kerravala -- back-end adoption of Ethernet and the virtualization of servers are creating increasingly complex network environments that -- partly because of Ethernet's considerable packet loss -- are more error prone.
Another major development in Ethernet that could change how enterprises build out their infrastructure is the new standard for Power over Ethernet (PoE). The draft standard, 801.3at (dubbed PoE+), allows up to 30W of power, twice the amount of the current 801.3af standard. To achieve this, PoE+ uses all four pairs of Cat 5/6 cables instead of the two utilized in typical PoE.
This development could eventually allow engineers to power entire workstations using Ethernet, according to Kerravala. "Historically, it was phones and cameras that were powered," he said. "But I think we're going to start seeing Ethernet being used to power laptops and even desktop workstations."
While allowing for a greater breadth of hardware that can be powered through Ethernet cabling, PoE+ raises issues of energy use. "The downside to this is that you may require even larger power supplies, bigger fans and more heat dissipation," Passmore said, "which brings the issue that typical phone closets were never designed for that sort of heat buildup."
Creating greener technologies isn't necessarily the concern of switch manufacturers, though. "I think that's important, but if you look at overall power consumption, it's less than 20% in the network," Kerravala said. "There are other places within a corporation to conserve energy. So while it's a good development, it's not a selling point."