By Bill Robbins
FCoE is a convergence of two technologies—Ethernet networking and storage—through a single unified fabric that allows Fibre Channel storage traffic to move across high-speed Ethernet infrastructures after some modification. As such, the reach and capabilities of SANs can be extended while protecting existing investments in storage networks.
The ANSI T11 standards committee received the proposal to review FCoE in April 2007. ANSI is also evaluating proposals that will make Ethernet a “lossless” technology capable of supporting Fibre Channel traffic (see sidebar on p. 32).
FCoE network switches and converged network adapters (CNAs) were announced by vendors such as Cisco, Emulex, and QLogic this spring. FCoE-capable switches were announced by Cisco and Brocade. And the modifications to the Ethernet standard, as well as the FCoE standard, are expected to be finalized by early next year.
But as many companies begin to put their toe in the FCoE water, some are beginning to see potential organizational conflicts that could possibly slow implementation.
“The challenge is bringing two organizations—the networking team and the storage team—together, which in the past, have been typically siloed,” says Joe Gervais, senior director of marketing for Emulex. “We’re talking convergence, so it’s going to take a lot more cooperation than what we’ve seen in the past with these two groups. Convergence isn’t hinged on technology, but on a mindset of organizations coming together.”
FCoE is also challenged with a variety of moving parts within the industry that will have to come together. The FCoE ecosystem is expansive, with a variety of vendors in the storage, adapter, and switch markets. No one vendor can bring the technology to market by simply voicing support or by delivering a single component. It will require multi-vendor solutions to bring FCoE into a complete infrastructure play.
However, FCoE promises a number of benefits, including the consolidation of rack space. By increasing network bandwidth through consolidation into fewer servers, FCoE begins to free up space in the data center. With the reduction in the number of servers and the introduction of CNAs that replace the myriad of Fibre Channel host bus adapters, Gigabit Ethernet network adapters, and server interconnect adapters, also comes a reduction of cabling.
In some cases, FCoE is expected to reduce the number of networks from three to one over time, providing more computing power in a smaller footprint. Fewer servers mean fewer cables and less energy consumption, which leads to “green” data centers.
Not easy being 'green'
Deepak Munjal, Cisco’s manager of data-center marketing, says the green computing aspect of FCoE is based less on environmental concerns than on the reality of limited power supplies. “The amount of power coming from our utility companies is obviously not limitless,” says Munjal.
“Companies are growing increasingly concerned about running out of power. So anything they can do to reduce power by simplifying and consolidating their networks will allow them to make better use of the power they have.”
Beyond the issues of cabling and energy consumption, data-center managers will likely gravitate to FCoE because of its ability to protect existing investments in servers and network infrastructure. FCoE promises seamless integration with existing Fibre Channel and iSCSI storage devices. With CNAs offered by Emulex, QLogic, and others, the technology covers both IP and Fibre Channel.
“The beauty of FCoE is that customers can use all of their existing Fibre Channel storage products from any vendor, and when deploying new servers, they can use CNAs and still be able to connect to their existing Fibre Channel storage,” says Amit Vashi, vice president of marketing for QLogic’s Host Solutions Group.
Vashi adds that FCoE further advances the cause of investment protection with common operating system drivers and applications. SAN management software, for example, will work the same way it does now, but with greater performance, simplified management, and easier integration with Ethernet technology.
Despite expectations by users and vendors, FCoE adoption will depend largely on how quickly enterprises will take the plunge and how quickly others will follow. If the economy slips further into a recession, then it is possible that data-center managers will want to play it safe and avoid new technologies such as FCoE—regardless of its promises.
Ian Whiting, vice president and general manager of Brocade’s Data Center Infrastructure Division, predicts that some FCoE products will be available by year-end or early next year, but he doubts that significant adoption will occur until 2010. Whiting believes pricing could serve as an impediment.
“There is a misconception that FCoE will be at or less than the price of existing solutions,” says Whiting. “The reality is that we don’t really know, but as with any new technology initially the prices will be high because there will be limited supply and choices.”
However, Cisco’s Munjal notes that demand is growing for a simplified, converged network environment and for lower energy costs.
“The only question is what technology will take us there. The next six months are going to be very telling,” he says.
Making Ethernet a ‘lossless’ protocol
Implementing Fibre Channel over Ethernet (FCoE) requires enhancements to the Ethernet protocol. Because Ethernet deals with congestion by dropping packets—an occurrence that would not be tolerated in Fibre Channel environments—Ethernet needs to be enhanced to make it a “lossless” protocol.
Vendors working through the ANSI and IEEE standards organizations have proposed a number of modifications to the Ethernet protocol. These changes will alleviate the latency of a congested network and ensure that Fibre Channel packets make it through to their destination in the order intended.
The changes to the Ethernet protocol are termed Converged Enhanced Ethernet (CEE) and include Per Priority PAUSE, congestion management (CM), CM discovery and capability exchange, and priority processing/packet scheduling.
- Per Priority PAUSE provides a mechanism at the congestion point to support differentiated services and to minimize or eliminate the dropping of packets due to congestion;
- CM and CM discovery and capability exchange—Two modifications to the 802.1 specification will provide link-level congestion management for unicast traffic in networks with long-lived data flows with respect to bandwidth-delayed products. The end-to-end congestion management enhancement—802.1Qau—provides for the throttling of end stations when congestion occurs in the network, thus relieving congestion. CM discovery and capability exchange provides a mechanism to define the domain formed by CM-compliant bridges and end stations to ensure interoperability. Another enhancement—P802.3ar—specifies a mechanism to support the communication of congestion information, and limit the rate of transmitted data on an Ethernet link, while preserving existing Media Access Control/Physical Layer Signaling (MAC/PLS) service interfaces; and
- Priority processing/packet scheduling provides for classes of traffic with differentiated service so that high-priority traffic gets transmission priority in end stations and switches.
These enhancements, which should be ratified by year-end, will enable Fibre Channel traffic to run over Ethernet.
Adoption of FCoE won’t happen overnight; it will occur in stages. The figure below shows a typical scenario prior to the use of Converged Network Adapters (CNAs). A server that is attached to the network, storage, and other servers may contain as many as six network adapters, host bus adapters (HBAs), and host channel adapters (HCAs). By replacing these adapters with CNAs (from vendors such as Emulex and QLogic) IT administrators can reduce not only the number of adapters in the server, but also the amount of cabling necessary to wire the infrastructure, as shown in the figure, left.
To preserve investments in Fibre Channel, Ethernet, and InfiniBand, users will also adopt switches that have FCoE capability as a bridge to full convergence (see figure, top) investments.
Brocade outlines FCoE plans
By Kevin Komiega
At its annual meeting for investors and analysts earlier this summer, Brocade executives detailed the company’s latest products and tempered some of the hype and expectations swirling around the availability of Fibre Channel over Ethernet (FCoE) and Converged Enhanced Ethernet (CEE) networking technologies.
FCoE is an emerging storage protocol that will allow Fibre Channel traffic to travel over Ethernet networks. CEE is a necessary piece of the puzzle as it turns unreliable Ethernet networks into a “lossless” transport mechanism.
However, there is some debate among vendors and analysts as to when FCoE products will be available to end users.
A cadre of companies, led by Cisco, Emulex, and QLogic, demonstrated FCoE-capable switches, adapters and cabling products at the Storage Networking World show in April—an event dubbed by many as FCoE’s coming-out party.
Cisco debuted the Nexus 5000 series of data center-class switches, which are essentially 10GbE switches with optional software licenses that allow users to turn on FCoE functionality once the standards have been ratified.
QLogic threw its hat in the FCoE ring with a line of converged network adapters (CNAs) that support FCoE connectivity. Emulex also participated in the SNW demo session by displaying a line of FCoE-based CNAs. And Intel announced support for FCoE on its family of 10GbE server adapters.
Compared to some other vendors, Brocade is offering what it terms as a more pragmatic timeline for FCoE and CEE-based products, stating that the technologies are likely to be adopted by customers incrementally, to extend their existing networks, with greatest impact initially on the server side of the data center.
Ian Whiting, vice president and general manager of Brocade’s Data Center Infrastructure Division, says FCoE and CEE technologies will not be ready for prime time this year.
“Standards-based FCoE products will come into the market at the end of this year and the early part of 2009,” predicts Whiting. “Next year will be when end users begin trying it out, and 2010 will be the year we’ll see adoption on the server side.”
End-user survey results from TheInfoPro (TIP), an IT research firm, support Brocade’s views that while users are aware of these developing technologies, their plans are to carefully assess and evaluate the impact of the new standards prior to deploying the technologies in production environments.
TheInfoPro recently polled storage and networking users from 152 Fortune 1000 companies and found that 84% of users have no immediate plans to deploy FCoE, with only 9% stating that FCoE deployment is in their long-term plans.
Whiting says Brocade will begin delivering rack switches and HBAs once FCoE and CEE have been vetted by the standards bodies later this year. However, he does believe that users need to adjust their thinking about data-center designs now in order to be ready once the technologies are available.
“If you believe some of the press out there, FCoE is going to happen next Tuesday and it’s going to be cheap and easy to use, but in reality, it’s going to require a different switch and adapter infrastructure,” says Whiting.
In the meantime, Brocade is pushing hard to convert IT professionals into true believers when it comes to its Data Center Fabric strategy with new products such as the DCX Backbone platform and the company’s recently released 8Gbps Fibre Channel SAN switches and HBAs.
Brocade’s FCoE products are expected to include FCoE and CEE module options for the DCX Backbone platform, a 10Gbps FCoE switch in a “top-of-rack” model or as an edge switch, and 10Gbps FCoE server adapters.