Ten Gigabit Ethernet -- the latest and fastest version of the ubiquitous data networking protocol -- is also coming to the networks that link storage arrays to each other and to servers.

Questions yet to be answered include: How quickly will iSCSI networks running 10 Gigabit Ethernet hardware become mainstream? Which applications will it be used in? And how much of the high-end storage market will be left for Fibre Channel (FC), which is now the protocol of choice for applications which require the very fastest, most reliable storage?

"Over time, things like even mission-critical applications will be run on iSCSI," says Larry Hart, a senior manager in the storage and networking group at Dell Inc. "More and more customers are starting to say yes" when asked if they would trust transactional applications and the like to the protocol, he says.

According to this view, the eventual lower cost of 10 Gigabit Ethernet hardware, combined with the easy availability of trained Ethernet administrators, makes it likely that most companies will eventually run a single, combined data and storage network on Ethernet.

Others insist Fibre Channel is far from dead. They argue 10 Gigabit Ethernet running on iSCSI is still unproven for the most mission-critical applications. They also question how many applications need that much throughput and point out that 10 Gigabit Ethernet will require costly switch upgrades or network interface cards until servers ship with 10 Gigabit Ethernet ports.

See our sidebar story on Fibre Channel over Ethernet: "FCoE: Fibre Channel's last stand".

But there's one thing everyone agrees on: 10 Gigabit Ethernet will bring major changes to the way organizations buy and manage their storage networks.

While it is only now gaining visibility in the storage world, 10 Gigabit Ethernet was ratified in 2002 and is already in use in many data networks. One delay is due to the fact that running just Gigabit Ethernet means most transactional applications don't face network bottlenecks.

However, some users are buying 10 Gigabit Ethernet switches to speed traffic among switches at the core of their networks, known as interswitch links, which otherwise would slow under all the data coming over multiple Gigabit Ethernet links. Internet service providers, application service providers and storage service providers are among those who need the 10Gbit bandwidth at the core of the network for applications such as remote replication and disk-to-disk backup.

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