Multihop FCoE highlights Cisco's data center network product blitz

Cisco Systems and Brocade have marketed Fibre Channel over Ethernet (FCoE) as a key technology for data center network convergence and all-Ethernet data centers, but until now a lack of multihop FCoE products has limited FCoE adoption to server racks.

Cisco changed that this week, outlining a laundry list of new data center network products and features that include multihop FCoE capabilities, with support for the technology in its Nexus 7000 chassis switches and its MDS 9500 Fibre Channel director switches. Previously Cisco only supported FCoE on its Nexus 5000 switches. Now enterprises that want to invest in FCoE can converge data and storage networks from the edge into the core.

"The most significant argument that FCoE naysayers have been using to date is that there is no motivation or justification to use FCoE if it has to be within one hop of your compute resources," said Mike Spanbauer, senior analyst with Current Analysis. "It seriously impinges the ability to leverage the economics of Ethernets. You can't route to or collocate your storage in some other location in the data center. It has to be close to the compute racks. Multihop FCoE gives you more flexibility."

Still, making FCoE feasible from the edge to the core won't mean immediate uptake by network managers. Many network engineers believe that iSCSI, which can run natively over Ethernet, is the best way to achieve data center network convergence. What's more,  many still have viable and expensive investments in Fibre Channel networks, so they're in no hurry to rip those investments out and replace them with Ethernet.

"I'm not convinced that 10 Gigabit Ethernet FCoE makes sense because most customers that have 8 Gigabit Fibre Channel don't think the 2 gigabit difference is a big improvement," Spanbauer said. "When 40 Gigabit Ethernet comes -- versus 16 Gigabit Fibre Channel -- that changes the game entirely. That's when we'll start to see significant change."

Matthew Norwood, a network architect with a Tennessee-based healthcare enterprise, said his data center doesn't really have a need for multihop FCoE today, but it's nice to know it's there if he needs it someday.

"The only time we would implement FCoE is if we used UCS [Cisco's Unified Computing System]," Norwood said. "We have Fibre Channel switches that are going to be here for several years to come. Multihop FCoE is great, but how many people are actually starting to use it? For new installs and data center redesigns, OK, but to go purely FCoE and rip-and-replace? I don't know if we're going to see that.”

Beyond multihop FCoE: Addressing the network-storage team clash

Beyond extending FCoE from the edge to the core, Cisco's latest release also tackles another data center network convergence barrier: Making resources equally available and manageable to both networking and storage teams. Already, the Nexus 7000 has the feature Virtual Device Context (VDC), which enables network engineers to make Ethernet resources available to storage teams by logically partitioning a Nexus 7000 into separate virtual devices.

"VDC allows me to virtually segment a Nexus 7000," said Stuart Miniman, principal analyst with Wikibon. "I can now go to my storage administrator and say, 'Here is your logical Ethernet switch. You own it.' It's for those [storage] guys who say they are not comfortable and don't want to go to the LAN group."

Cisco has now announced that it is converging its data center LAN and SAN management software products into a single platform, the Data Center Network Manager, which allows both SAN and LAN teams to manage their respective domains through a single system and enables simpler collaboration between those teams. Now both the storage teams and the network teams will use the same software to manage resources on logically segmented Nexus 7000s and other shared infrastructure.

New top-of-rack Nexus switches announced, including one for high-frequency financial trading

Cisco also unveiled the Nexus 3000, a 1 RU, 48-port Gb/10 Gigabit Ethernet (GbE) switch designed for high-frequency trading applications. Cisco claims the Layer 2/Layer 3 Nexus 3000 has ultra-low latency of just one microsecond from port to port.

Cisco also announced a new generation of the Nexus 5000 switch series, the Nexus 5548 UP and 5596 UP. These 48- and 96- port switches feature Unified Port (UP) capabilities, meaning any port on the device can be configured as gigabit, 10 GbE, FCoE or 8 Gigabit Fibre Channel ports. The Nexus 5596 UP can also connect to as many as 24 Nexus 2000 Fabric Extenders, and both models will support FabricPath, Cisco's version of TRILL, in the second half of this year. Both of these switches will have Layer 3 features, a first in the Nexus 5000 line.

Cisco expands Fabric Extender concept to NICs, virtual machines

Cisco also expanded its Nexus 2000 Fabric Extender (FEX), which extends the ports of an Ethernet switch across a wire without creating a new point of management. Originally just compatible with the Nexus 5000 family, the Fabric Extenders now directly attach to the Nexus 7000 line.

The Nexus 7000-FEX compatibility potentially allows enterprises to create large-scale, single-tiered data center networks, especially if Cisco continues to build up the overall port-density of the Nexus line, said Spanbauer.

Cisco has applied its Fabric Extender technology to network interface card (NIC) and virtual machine (VM) management, too. Adapter FEX software, which will run on third-party server NICs, will allow network engineers to logically partition 10 Gb NICs into as many as four virtual NICs, allowing network engineers to set and enforce separate network and security policies on a server through a network switch.

"On a single physical NIC, you can have four vNICs that you can treat independently," said Craig Huitema, director of marketing for data center solutions at Cisco. "If you want to apply different policies on each one, you can have associations exclusively for certain VMs."

That network control will also be extended from the NIC to VMs residing in the virtualized server with Cisco's new VM-FEX software. This technology is based on Cisco's VN-tagging technology, which IEEE is standardizing as 802.1Qbh.

These new features appear similar to what HP is doing with its Virtual Connect FlexFabric technology, said Norwood.

"I would love to see capabilities from Cisco on par with Virtual Connect, in terms of being able to carve up a NIC into logical spaces," Norwood said. "We're a huge HP blade enclosure shop, and they've had a lot of firmware issues of late. Cisco makes an Ethernet switch that can go on the back of an HP enclosure, and Blade [Network Technologies] does, too. You can replace the Virtual Connect modules, but you can't replace that functionality.”

The Adapter FEX may be an alternative to Virtual Connect without having to go with full-blown Cisco UCS, he said.

Cisco will make $10,000 license activations for multihop FCoE on the Nexus 7000 in the second quarter of 2011.

Let us know what you think about the story; email Shamus McGillicuddy, News Editor.