iSCSI as the Converged Fabric

Arthur Cole

When you think of converged data center network, the first thing that pops into your mind is Fibre Channel over Ethernet. Since Ethernet is likely to form the backbone of your infrastructure, it only makes sense that the most significant challenge will be to bring Fibre Channel into the fold.

For many organizations, though, it's becoming clear that the answer to unified networking lies in a protocol that is already at home on the Ethernet: iSCSI.

As Network World's Jim Duffy pointed out recently, the chief obstacle to relying on iSCSI as a network fabric is its lossy nature. Some smaller organizations can get away with dropping a few packets here and there, but larger groups running high-speed apps rely on the lossless environment of Fibre Channel networks. But what if you were to run an iSCSI fabric across one of the new lossless Ethernet Data Center Bridging devices current up for standardization at the IEEE? In that way, you gain a single infrastructure based on iSCSI and backed by advanced data-flow capabilities that alleviate both the lossiness and latency issues of standard Ethernet.

Clearly, there is an expectation that iSCSI will be part of the unified fabric going forward. EMC, for example, recently certified Emulex's OneConnect CNAs, which accommodate both 10 GbE iSCS and FCoE, for itsConnectix, Clariion, Celerra and Symmetrix lines. The move marks the first time that the EMC Select integration program has offered an iSCSI solution.

And it's not like iSCSI is being relegated to low-level applications either. Super Micro Computer recently turned to RelData for the iSCSI component of a combined storage solution aimed at high-performance environments. The package combines Super Micro's SYS-6036ST-6LR bridge system with the RELvos software platform, delivering such advanced features as integrated clustering, replication and data migration.

All of this begs the question whether the unified networking movement will get bogged down in the same arguments that have plagued the industry for so long: Fibre Channel vs. iSCSI; block vs. file, SAN vs. NAS. According to Enterprise Storage Forum's Jennifer L. Schiff, the answer is not likely. Unified storage is all about not choosing sides. The beauty here is that it provides a common framework for all protocols, even if one emerges as the underlying backbone on the network. In that way, users and applications can find the ideal storage to suit their needs rather than be crammed into whatever box IT finds suitable to provide.

By and large, the decision on which protocols to employ in a converged setting will depend largely on what kind of infrastructure is already in place. Those with Fibre Channel will likely find FCoE the most convenient solution. But even those with an abundance of iSCSI will be able to use legacy infrastructure to the fullest and still provide a robust framework for all users.

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Add Comment      Leave a comment on this blog post
Apr 16, 2010 11:43 AM J Metz J Metz  says:

I think the title of the article is misleading. Part of this has to do with a definition of terms (I wrote about this on my blog a couple weeks ago: http://bit.ly/92n4Qa).

iSCSI, in-and-of-itself, is not a convergence technology. It can be used within a converged environment, and the article describes using iSCSI within a DCB environment, but that is using DCB as the convergence catalyst, not iSCSI.

It is far easier to incorporate iSCSI (along with FCoE) into DCB than FC into iSCSI.


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