The melding of SCSI and Ethernet allows companies to get essentially the best of both worlds. They can, for example, use iSCSI as a way to move storage traffic across long distances and use a remote SAN for storage. They can also back up their local storage at great distance, and they can use a single 10Gbps pipeline to consolidate all of their traffic, something they can't do using more traditional storage technology.

Finally, there is the issue of management. Although virtually all NAS and SAN products have had some level of management, almost everything has been proprietary. If you had an IBM Shark handling your storage needs, for example, you couldn't plan on using the same management software to handle your NAS traffic. With iSCSI, the network portion of the management issue is simplified. You can use the same network management tools you use for your other network management, just as you use the same switches and routers.

Overall, iSCSI offers a lot in terms of both simplicity and flexibility. That does not mean, however, that there are no downsides. In fact, there are two that should be mentioned up front.

The first is that encapsulating SCSI commands inside an IP packet adds overhead. After all, you have to pass all those IP and TCP headers, checksums, and the like along your network in addition to the SCSI commands that are the actual payload. There is less overhead on a Fibre Channel SAN, and none at all on a direct SCSI connection.

Second, not all management is created equal. Although your network management software may work with iSCSI as well, that doesn't mean that you will be able to manage the iSCSI device itself without resorting to proprietary software. And you can assume that each company will develop its own device-level software that won't work with products from other companies.

Finally, there's the security issue. SCSI commands aren't secure because they never had to be. The SCSI protocols were developed with the idea that they would be traveling on cables embedded in a single computer. Now that you're transmitting your storage traffic across an external network, perhaps even the Internet, anyone with access can read your traffic. Better plan on encryption to protect your data.

BOTTOM LINE

iSCSI
EXECUTIVE SUMMARY
iSCSI is a significant enhancement to previous network storage technologies because it manages to simplify and expand the storage equation. On one hand, it uses familiar protocols; on the other hand, it extends the range of communication, eases management, and increases available bandwidth. iSCSI should also be easier and less expensive to implement than current storage technologies.

TEST CENTER PERSPECTIVE
The release of the final iSCSI standard is certainly significant. With iSCSI, your company's network storage solution is suddenly easier to implement, has better manageability, costs less, and goes faster. That's rare in any technology. The downsides to this storage protocol are few and minor, and the advantages are significant. For most companies, a move into iSCSI is a win-win situation.