For many broadcasting entities and creative agencies with multiple users moving large files across a network, Fibre Channel was a sensible alternative. Originally created as a better network for storage, Fibre Channel was meant to be lossless and redundant, as well as offer features that Ethernet did not. This was critical because storage doesn't do well when commands or packets of data are dropped, which causes problems with the operating system. Fibre Channel's biggest drawback, however, has been cost to implement, due to infrastructure requirements associated with installation.
Since the introduction of Fibre Channel, Ethernet has continued to grow and “suck in” more technology, such as switching, flow control and better congestion management. As a result, the cost and difficulty in continuing to make faster and faster Fibre Channel chips has been magnified, especially when taking into consideration that the FC protocol can run over Ethernet to achieve similar performance at a fraction of the cost. Ethernet is on every motherboard, and 10GigE will begin to appear on motherboards within six months. Thus, the shift to Fibre Channel over Ethernet (FCoE), which enables professionals to run FC over inexpensive, ubiquitous, standard Ethernet.
Circumventing TCP
Taking advantage of 10GigE's robust throughput capabilities, Small Tree's Leaf Host Bus Adapter running ST-FCoE — a stand-alone initiator with one to six 10GigE ports — will offer maximum efficiency and ease in handling 10-bit HD uncompressed video or next-generation 8K video.
FCoE rips out the physical layer — the chips, cable, lasers, etc. — and replaces it with the Ethernet layer. This circumvents having to use TCP, which is the standard protocol over Ethernet to move data around. TCP makes sure data packets are correct and arrive in order and on time. For years, network vendors have tried to bury the TCP stack down in the network card to make it go faster, and it's never been easy.
The beauty of FCoE is that the stack doesn't have to change. Using Direct Data Placement (DDP), Small Tree's 10GigE network card takes data sent from the remote card and dumps the data right into memory. The card doesn't have to communicate with the CPU via TCP before the data appears in the user's space. This reduces the CPU workload, enabling the system to run much faster and the network card to perform like a storage card.
Converged networking
While working on a 10GigE driver for Intel and its latest 82599 chip, it became clear that we should add a storage driver to the card. Leveraging our previous experience with the AoE and iSCSI protocols, we created a storage driver and GUI for Mac OS X. This allows Mac users as they are moving to newer, faster storage to purchase an open 10GigE switch that will support FCoE and old-fashioned Fibre Channel over one plug. This is converged networking.
What impact will this have in the broadcast industry? Users on the new Westmere Mac Pros will be able to put a six-port 10GigE card in the machine, dedicate three of the ports to storage and dedicate three ports to broadcast. In just one 16x PCIe slot, you will have 60Gb/s of bandwidth, one way, that can be used to broadcast MPEG, or whatever format you're broadcasting, with low latency because it's all offloaded with no TCP involved.
Ethernet features a new flow mechanism that makes it lossless so that FC packets are easily passed over the network with no loss of performance. QoS capabilities, ensuring important storage data is prioritized ahead of less important data, are also available with FCoE. In fact, unimportant traffic is dropped by the new flow control mechanism, helping to assure FCoE storage packet arrival to the user.
Fibre Channel loses the war
With the increasing shift to 10GigE and the ubiquity of Ethernet, Fibre Channel has lost the war. It's too expensive and is not easily scalable, making it an unattractive alternative to companies expecting to grow in the future. FCoE takes advantage of technology that already exists, eliminating the need for reconfiguring your entire infrastructure. FCoE systems, with one cable handling both storage and networking, will simplify the physical cabling layouts and storage purchasing decisions.
Steve Modica is the CTO of Small Tree.
