Dualies Aren’t Just for Trucks

This article was originally published in April of 2009 at 10GbE.net

One would think that after 30 years our industry would have developed a NIC naming convention for “dual-port.” Does a dual-port NIC mean your OS sees one or two interfaces? Do dual-port NICs mean that one port is active and the other is for fail-over? Can a dual-port run traffic through both port simultaneously? It all depends on who you talk to, and the product they’re selling.

With 10GbE we’ve seen three main approaches for building dual-port NICs:
Active/Active: this is what most people expect, a single OS interface with a driver that sprays traffic fairly evenly across both network ports and if one port fails the other picks up the slack until it can handle no more:
  • Chelsio’s N320E for $790 is an example of this type of card.
  • Intel’s AF DA card for $799 appears to be another example of this class of card.
Dual-NIC: two OS interfaces are presented to the OS and both interfaces run independently. This typically affords the best performance and the most flexibility:
  • Myricom’s 10G-PCIE2-8B2-2S+E for $995 appears to be the only example of this approach. Myricom utilizes two unique 10GbE controllers on the same PCI Express Gen2 NIC and a PCI Express bridge chip to break the slot into two unique NIC devices.
Active/Passive or Active/Fail-over: a single OS interface with a driver that monitors connectivity on the active port and if the connection fails the driver migrates traffic rapidly over to the second port:
  • Myricom’s 10G-PCIE-8B-2S+E for $795 is an example of this type of card. The fail over time is under 10 microseconds.
  • Chelsio’s B320E Bypass adapter for $3,483 is similar but it can detect an OS/BIOS/System failure and make a hard switch over to the second port.
Do the above categories cover it, or do we need more lingo? When looking for a dual-port NIC, what features do you require, and what do you expect? Please let us know.
P.S. As I brought this page back online I left off the links as most no longer apply, but from a historical perspective it is interesting to see how things have progressed.

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