ATA Over Ethernet - Protocol Description

Protocol Description

AoE runs on layer 2 Ethernet. AoE does not use internet protocol (IP), it cannot be accessed over the Internet or other IP networks. In this regard it is more comparable to Fibre Channel over Ethernet than iSCSI.

With fewer protocol layers, this approach makes AoE fast and lightweight. It also makes the protocol relatively easy to implement, provides intrinsic security protections by virtue of its being non-routable, and offers linear scalability with high performance. The AoE specification is 12 pages compared with iSCSI's 257 pages.

AoE Header Format:
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 0 | Ethernet Destination MAC Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 4 | Ethernet Destination (cont) | Ethernet Source MAC Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 8 | Ethernet Source MAC Address (cont) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 12 | Ethernet Type (0x88A2) | Ver | Flags | Error | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 16 | Major | Minor | Command | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 20 | Tag | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 24 | Arg | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

AoE has the IEEE assigned EtherType 0x88A2.

Read more about this topic:  ATA Over Ethernet

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