Slowly but surely, networking vendors are rolling out data center fabric technologies that will enable enterprises to build out large, Layer 2-based data center networks to support virtual machine mobility and private cloud computing.
Brocade announced its VDX series of switches this week, a line of Layer 2 Ethernet switches that use the emerging IETF protocol Transparent Interconnection of Lots of Links (TRILL) to create large, multipath Layer 2 Ethernet fabrics. The first generation of these switches, the VDX 6720, is available today.
Cisco Systems announced its own flavor of TRILL-based Layer 2 networking, FabricPath, in June. Its solution consists of a $25,000 license activation for its Nexus family of data center switches -- dubbed the Enhanced Layer 2 License for FabricPath -- and a $35,000 F-Series I/O module for the Nexus 7000 chassis. The F-Series module started shipping last month..
Many networking vendors are developing data center fabrics that enable large, flat, Layer 2 networks to eliminate the choke points associated with spanning tree protocol and facilitate the mobility of virtual machines across data center network infrastructure. Zeus Kerravala, distinguished research fellow with the Yankee Group, pointed out that Avaya has embraced Shortest Path Bridging - an emerging IEEE protocol that is very similar to TRILL - for its data center fabric, the Avaya Virtual Services Platform. Juniper Networks appears to be developing a more proprietary technology with its Project Stratus.
"Data center fabric is the product du jour nowadays," Kerravala said. "There is nobody who would argue that today's current enterprise networks are designed for broader use of virtualization and vMotion. Spanning tree protocol has been long outdated and needs a revamp. That's where all these fabrics come from."
Data center fabrics support virtual server networking
Enterprises see large Layer 2 data center fabrics as the future of virtual server networking. These Layer 2 domains will expand the mobility of virtual machines (VMs) beyond server racks. In a Layer 2 network, the VMs can go anywhere in a data center and eventually travel across multiple data centers. This is a basic building block for cloud computing, and data center network infrastructure vendors are inching toward delivering this technology.
"I think they're all trying to get to the same place... the whole virtualization piece,being able to fail over from one data center to another," said Matthew Norwood, network architect with a Tennessee-based health care enterprise. "You're seeing TRILL is finally getting the point where it's going to be rolled out and everyone is going to have their own implementation of it before a full-blown TRILL standard is available."
Large Layer 2 data center networks may get server and virtualization administrators excited, but they make network engineers nervous. In a Layer 2 network with any-to-any connectivity, enforcing security and policy, as well as and monitoring and managing performance, can be challenging. There is no central point where an engineer can monitor and secure the network.
"As you see technologies come out that get around the spanning tree [limitation], now you're seeing vendors say, 'Well, OK, if I don't have this limitation anymore, why in the world should I make things more complicated and have a bunch of Layer 3 segmentation when I can have one big, flat Layer 2 network?'" Norwood said. "That's great for people who are managing servers and virtualization, but it's a little more difficult for those of us on the network side who have to make everything work efficiently because, obviously, the larger my Layer 2 domain gets, the harder it is for me to keep an eye on the traffic. I think it's going to take a while for everything to settle down to the point where we can have these large, multi-data center, Layer 2 networks that function properly and efficiently."
Brocade will be rolling out a feature called Dynamic Services in its VDX switches, said Doug Ingraham, Brocade's vice president of product management for data center products . This technology will allow enterprises to apply services like security and application delivery controller functionality across an entire data center fabric. He said Brocade will work with partners to deliver this, so that enterprises can deploy the services either on virtual machines or in physical appliances and have them cover the entire network.
Brocade simplifies data center fabric buildout and management
Simplicity is a key element to Brocade's VDX switching line, according to Ingraham. He said each of the VDX 6720 switches can auto-discover and auto-configure each other to form a large Layer 2 cloud of switches that appear logically to the rest of the data center network infrastructure as one large switch. Network administrators will be able to manage all of the switches as a single virtual chassis. This feature is somewhat similar to the virtual chassis technology that Juniper has had in its EX series of switches for a couple of years.
"We're moving to an environment where the whole focus is around managing pools of resources - not managing boxes," said Joe Skorupa, research vice president with Gartner. "One of my clients recently commented: 'As soon as one of my technicians has to sit down and touch the CLI [command line interface], we've lost.' The Brocade mindset is, you have X number of ports and you figure out what you want to plug into them. But you don't worry about which physical switch you plug into. You worry about what resources are connected, not where the physical boxes are."
The first VDX switches are the VDX 6720-24 and 6720-60, 24 port and 60 port 10 Gigabit Ethernet, fixed-configuration switches. Both switches ship with the option to activate additional ports through a licensed upgrade. The 6720-24, for instance, ships with 16 active ports at a starting price of $10,700. For an additional license fee, enterprises can activate the other 8 ports. Ingraham said Brocade will deliver a Gigabit version to the market in early 2011 and a modular chassis VDX in late 2011.
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