– Saqib Jang with the Data Center Products group at Brocade (www.brocade.com), says:
The new Fibre Channel over Ethernet (FCoE) protocol standard has the goal of allowing an evolutionary approach to 10 Gigabit Ethernet (10 GbE)-based I/O consolidation in the data center by preserving all Fibre Channel (FC) SAN constructs – maintaining the latency, security, and traffic management attributes of FC, while preserving investments in FC tools, training, and SAN infrastructure. FCoE enables the transport of FC storage traffic over a new lossless Ethernet medium, Data Center Bridging (DCB). FCoE runs over Ethernet and does not utilize TCP/IP; thus avoiding the ‘best effort’ network delivery and server CPU processing (especially at 10 Gbps or higher data rates) limitations of the TCP/IP protocol stack.
The massive scale of the architectures emerging in enterprise and cloud data centers has created an opportunity for the evolving data center network to play an important, unprecedented role in data center management. The added attention being paid to data center networks is forcing customers to consider alternative data center network architectures that they may not have considered adopting before, including the key initiative of I/O consolidation.
The interest in FCoE is connected to the trend toward data center I/O consolidation. As far as server, storage networking and storage systems are concerned, this translates into customers purchasing fewer host bus adapters (HBAs) and network interface cards (NICs), fewer cables, and, ultimately, fewer switches and storage systems. This also reduces the utilization of PCI slots on servers, which is particularly beneficial with bladed servers, and helps to reduce power, equipment and administrative costs.
FCoE is a new technology that enterprises will initially deploy for risk-tolerant applications before they expand the deployment into the area of mission-critical applications. In the near term, FCoE will find a home in new server deployments in Windows and Linux environments with virtualized tier three and some tier two applications.
When looking at data center traffic, tier three servers providing web access generate traffic primarily composed of TCP/IP data. Both 10 GbE NICs and CNAs can easily service this class of servers and their related traffic. Tier two applications servers with business logic applications tend to host applications of higher business value to enterprises. These servers are normally connected to LANs and SANs, because their traffic is split between storage and TCP/IP.
Some tier two applications, such as e-mail, are good candidates for FCoE, and would benefit from server I/O consolidation. On the other hand, tier one servers tend to host mission-critical database applications that form the enterprise IT backbone. It is expected for businesses to deploy mature and reliable technologies for tier one servers and applications. In addition to that, tier one applications have a higher need for predictable performance at optimal processing overhead that will make customers continue to look to higher performing and reliable I/O technologies such as Fibre Channel. It is unlikely that FCoE will find its way into tier one environments in the near future even with 10 GbE transport, for speed is only one factor in tier one environments.
It is important to note that FCoE is an encapsulation protocol and not an FC SAN replacement technology. In fact, FCoE builds on the success of FC in the data center and utilizes FC along with new lossless Ethernet, DCB, to solve server I/O challenges facing IT professionals in data centers.