It's highly likely that, if you follow the comings and goings of storage networking technology, then by now you've at least heard of the emerging Fibre Channel over Ethernet (FCoE) standard. To the uninitiated, FCoE is a method of encapsulating the packets that would normally flow across a Fibre Channel storage network (SAN) for transmission over Ethernet link. Think 10 Gbps Ethernet for practical purposes. However, unlike other FC-to-Ethernet encapsulation methods like FCIP and iFCP, FCoE lives within the same OSI layer as IP, enabling enhanced performance, lossless frame transmission, and some other goodies.
Since the emergence of Fibre Channel SANs in the late 1990s, enterprise IT managers have maintained two sets of networks, one for storage I/O traffic and the other for data network traffic. But system consolidation and SAN expansion efforts are driving the need for a unified fabric where multiple traffic types — network, storage and clustering — are all carried over a single network infrastructure.
Several options to unify and extend the reach of storage networks have emerged over the last decade, including iSCSI, FCIP, iFCP and InfiniBand. But these options turned out to be performance intensive, too disruptive or, in the case of InfiniBand, required the introduction of new infrastructure.
To facilitate convergence and overcome the problems encountered with the other attempts, a consortium of storage and data network vendors came up with a new standard called Fibre Channel over Ethernet (FCoE). FCoE is designed to enable network convergence and cost-effective SAN expansion in the enterprise data centre. The basic concept is to use 10G Ethernet to carry native Fibre Channel traffic alongside standard network traffic.
There are many advantages of using the technology to expand SANs. “The many advantages of moving to a unified Ethernet fabric with FCoE, especially for data centres with large FC investments, begin with the simple reduction of equipment to manage. Extensions of the Ethernet standard known as Data Centre Bridging (DCB) enable a unified Ethernet network and allow FCoE to share the same wire with multiple data traffic types, including NFS, CIFS, iSCSI, as well as the rest of the LAN,” says Martyn Molnar, Regional Sales Director, NetApp.
DCB allows prioritisation of traffic types to maintain lossless transmission of the FCoE storage traffic while permitting lower service levels for applications that can afford temporary variability in transmission quality. Sharing the same Ethernet network fabric, from server to switch to storage, removes the requirement of a dedicated storage network, and therefore reduces the number of server adapters, cables, and switches required to support the data centre applications. “Not only can customers benefit from less equipment to purchase, but they will need less cabling and fewer switches, reducing power requirements and airflow restrictions. This can result in lower operating expenses. Less equipment also means less to manage and troubleshoot,” he adds.
Unifies management across Fibre Channel and FCoE fabric is another advantage. FCoE-enabled servers continue to leverage the Fibre Channel driver stack, multipathing schemes, etc. This enables enterprise data centres to leverage the existing Fibre Channel SAN management framework such as storage resource management tools and processes for FCoE-enabled servers as well.
FCoE also avoids the latency and complexity issues of TCP. The lightweight encapsulation used in FCoE avoids processing overhead and ensures high levels of end-to-end storage networking performance.
Work in progress
Fibre Channel over Ethernet is considered an initial step towards a converged data centre switching fabric. However, vendors say it is not driving the market for current data centre projects, as the market for FCoE is still in the gestation period with standards still fluid and pricing too high.
Khalid Khalil, Regional Sales Director for Brocade Communications, says he is not surprised to see the adoption of FCoE where it is today. “As a data centre technology, the deployment cycle for deploying FCoE is expected to be long and move in stages starting with familiarity with the new technology, testing phase that includes early testing and pilot programs, then finally deployment in operation environments. Unlike consumer electronics technologies, where purchasing decisions are almost instant, data centre technologies require planning that includes budgeting and finding the right applications and upgrade cycles for data centres. “
While we see few operations environment deployments, we notice a healthy level of testing and pilot program that will lead to higher level of deployment in 2010 and 2011. The world economy is recovering in many areas, the industry standards are ready, and storage and networking data and traffic continue to grow and need to be handled effectively with new technologies, he adds.
According to Molnar, the big setback for the adoption of FCoE is group alignment within an organization. One of the challenges iSCSI has faced at the enterprise is the political squabbling between the storage teams and the network teams as to who owns the network. In FC implementations the storage guys own the fabric, with iSCSI it's the networking group. In order for FCoE to succeed these two groups will have to align and work closer together than ever before and that maybe the biggest hurdle for FCoE to overcome, he says.
Though it hasn’t reached mainstream adoption yet, there is little doubt that FCoE technology provides an evolutionary approach to achieving high operational efficiencies within the network infrastructure. Besides unifying network fabrics, FCoE drives significant expansion of SAN access to a wider range of servers in the data centre.
FCoE technology and solutions present numerous advantages while ensuring the reliable performance characteristics required in data centre environments. As data centres transition to 10G Ethernet to meet the demands of blade servers and server virtualization environments, it is imperative for enterprise IT managers to deploy and evaluate 10G FCoE solutions. In addition to providing a competitive edge, FCoE technology paves the way for the next-generation, service-oriented data centre.
