Dec 12, 2014

ATA over Ethernet a ‘strict no’ in Data Center Networks

While exploring for storage networking technologies, there are chances that one can come across ATA over Ethernet (ATAoE). It is nothing but, ATA command set transported directly within Ethernet Frames. ATA over Ethernet approach is similar to that of a Fibre Channel over Ethernet (FCoE), but in reality the former has gained fewer acceptances from the industry.

As a matter of fact, ATAoE is limited to a single vendor (Vendor lock-in) and its specifications reveal that its protocol length is limited to 12 pages when compared with iSCSI, which has a 257 pages length of protocol.

Although, ATA over Ethernet was considered as an unsighted fast technology, it got overshadowed by the virtues of the iSCSI in the long run.

Storage networking specialists go with the opinion that ATAoE protocol is broken and so it is not a good recommendation to be deployed in the data centers. In order to further cement this statement, let us go into further details.
  • ATA over Ethernet has no sequencing- This protocol doesn’t support single sequence of numbers, which allow the storage arrays and servers to differentiate between requests or split a single request into numerous Ethernet frames. As a result of no sequencing, ATAoE offers its server the facility to go for a single request with a particular storage array.
  • ATAoE offers zero transmission- This protocol has no packet loss detection or recovery mechanism.
  • No fragmentation- ATA over Ethernet requests fit directly into Ethernet frames and so the fragmentation of a single request into multiple frames is not possible. As a result the achievement of data flow is almost zero. With the use of jumbo frames, the transfer of only two sectors is possible via each request.
  • Authentication is nil- This protocol if proposed for use in data centers, will not have authentication. So, as a result there is no network security in this protocol and so non-routability of AoE is a source of inherent security.
  • Asynchronous writes have weak support- Due to the absence of retransmissions and sequencing, asynchronous writes are handled in an in-considerate fashion.
The final word is that this protocol would have worked almost 30 years ago, when TFTP-Trivial file transfer protocol was designed. But now, in the present world, it will simply be treated as a broken protocol design class.

According to analysis of industry specialists, just go on with an ATAoE protocol to build a home network. For mission critical data center applications, ATA over Ethernet is a ‘strict no’.


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