Brocade's Software-Defined Networking and 100 Gb OpenFlow

Brocade is a bit late to the software-defined networking party, but the data and storage networking company has entered the SDN space in a big way, defining its position on the technology and supporting OpenFlow on its MLX routers, NetIron product family, ADX application delivery controllers and VDX switches. It has also announced a marketing, standards development and interoperation partnership with NEC, which makes an OpenFlow controller.

Brocade doesn't look at SDN and OpenFlow the same as other networking vendors. In its view of the network, the lowest tier is the network fabric, which is composed of the traditional L2/L3 switching and routing technologies in use today. Routing protocols like BGP and OSPF, forwarding technologies like spanning tree, TRILL and link aggregation work well and are well understood by network administrators. The data center bridging protocols make Ethernet lossless. On top of that, robust fabric is the network virtualization layer made up of overlay technologies such as VXLAN and NVGRE, which interconnect virtual machines via encapsulated tunnels or even MPLS, which is often used in WANs but is making an entrance into large data centers, providing a much-needed network layer that suits virtualized data centers well. SDN sits within the network services layer and provides the network operator--which, for Brocade, means carriers, cloud providers and the largest enterprises--with the ability to apply value-added services on top of the network.

At the top layer are cloud environments like OpenStack, CloudStack, VMware vCloud and Microsoft's Systems Center. It's this top layer where the cloud architecture communicates with the network via APIs that allow features like traffic separation for multi-tenancy, traffic grooming and service-level agreement management to occur.

While many consider OpenFlow a network fabric layer protocol, Brocade positions it as a network service layer. That's because its customers, carriers and cloud providers are already using existing L2/L3 protocols to build out the majority of their networks, and are looking at OpenFlow to provide a differentiated service to their customers who need special treatment. Robust networks can be built using existing technologies, but they're still best-effort, and network issues affect all traffic. Using OpenFlow on specific ports, VLANs or MPLS trunks, Brocade lets providers carve up their networks for specific customers while letting the rest of the network run dynamically. This hybrid-switch mode also allows companies to deploy OpenFlow in increments, without affecting the entire network.

Brocade's position is just that: a position. What it means for potential customers is they can run their traditional network alongside an OpenFlow network and move traffic between networks without having to exit and enter the switch--OpenFlow becomes a switch feature. The SDN component is where the cloud layer can treat the network as a service, similar to storage or compute. Brocade is already moving toward enabling services at L4-7 via its ADX controller, which can manage traffic flows, using Brocade OpenScript, and send them to an OpenFlow or traditional network. The ADX integration is a critical component in an environment where there may be many applications residing behind a single address, and those applications require differentiated services based on the content.

Naturally, a hybrid traditional switch and OpenFlow switch can complicate troubleshooting and problem resolution. Brocade has built-in instrumentation in the CLI that allow administrators to view the OpenFlow flow tables, show interfaces and manage how flows are processed through the switch, similar to the tools used in traditional networking.

Brocade's claim of being the first vendor to provide OpenFlow in hybrid mode is inaccurate. NEC's ProgrammableFlow switches are hybrid-capable, as are HP's switches, though HP does not yet fully support OpenFlow 1.0, according to its latest release notes for switch software K.15.06.5008. However, supporting OpenFlow on its largest routers and switches is a huge feat. Since OpenFlow support doesn't require new Ethernet framing like TRILL or Brocade's VCS did, the software upgrade means Brocade can support the 100 Gb interfaces in its NetIron routers and switches. As new versions of OpenFlow are stabilized, a software update is all that will be needed to upgrade.