There's more than one way to combine Ethernet and storage networking -- and make data centers vastly easier to manage A few years ago, if I had said I was running a “converged network,” you might have assumed I had just installed a shiny new network-attached VoIP phone system. Today, convergence has a completely different meaning. In conventional enterprise data centers, there are at least two networks: one built on Ethernet that allows users to access their applications on servers and a second one, often built on Fibre Channel, that enables those servers to access mountains of data on a storage network. Both of these networks are huge capital investments with their own specialized hardware. They have vastly different management tools and require completely different skill sets to build and maintain. Wouldn’t it be more cost-efficient to have just one network? That’s the promise of converged networking: one highly scalable, high-performance network with consistent management tools that can handle both Ethernet and storage traffic. This kind of convergence has been possible with IP-based storage protocols such as iSCSI for quite some time, but until recently it has never been a particularly viable solution for large enterprises. At first this was because 1Gbps Ethernet couldn’t handle the loads that enterprises throw at their 4Gbps and 8Gbps Fibre Channel-based storage networks. Now that the majority of large enterprises have upgraded to 10Gbps Ethernet, you’d think the problem had solved itself — except the needs of convergence go beyond having a really fast pipe. One of Fibre Channel’s strongest features is that it is an assured delivery protocol — meaning that, in a healthy network, no Fibre Channel frame is ever lost in transit. Ethernet was never designed to work this way. Instead, Ethernet networks have typically depended upon the Layer 3 and 4 protocols (such as TCP/IP) to recognize and adapt to network congestion and packet loss. Using these high-level protocols to implement flow control and error correction is both complex and expensive from a latency perspective. While these limitations are generally acceptable for most networking applications, they can spell disaster for a high-performance storage network that might be pushing tens and hundreds of thousands of disk transactions per second. In order for storage to leverage Ethernet and reap the benefits of running one network to rule them all, Ethernet had to grow up. And grow up it has. More than 50 of the biggest names in networking, servers, and storage have banded together to back the Converged Enhanced Ethernet (CEE) standard. This standard adds extensions to Ethernet that allow it to offer the same kind of policy-driven, lossless performance that Fibre Channel does, without requiring the overhead of high-layer protocols. These extensions — sometimes referred to collectively as “lossless Ethernet” — have allowed Fibre Channel over Ethernet (FCoE) to become a reality. But FCoE isn’t the only way to solve the convergence conundrum. As mentioned earlier, for “less than enormous” storage networks, iSCSI has grown well past its humble beginnings as a networked storage protocol for small business. With the availability of 10Gbps Ethernet and increasingly intelligent hardware and software to manage the flow of iSCSI traffic, iSCSI can be a very effective, and often much less expensive, alternative to FCoE. There are other convergence options. Take Xsigo’s virtualized networking platform: Instead of depending on an extended Ethernet standard to carry lossless storage and network traffic through the same pipe, Xsigo uses networking based on the high-performance InfiniBand standard to shovel both FC and general network traffic through the same 20Gbps or 40Gbps pipe. That InfinBand pipe runs from the server to an I/O director, which breaks that multipurpose bandwidth into native Ethernet and native Fibre Channel links. Whichever standard you choose, network convergence is a huge boon. Whether it’s being able to dynamically scale network and storage performance through the same interface or simply cutting down on the number of cables you need to keep track of, life is better in a converged world. This article, “What converged networking really means,” originally appeared at InfoWorld.com. Read more of Matt Prigge’s Information Overload blog and follow the latest developments in storage at InfoWorld.com. For the latest business technology news, follow InfoWorld.com on Twitter. Technology Industry