Nexus 7000 and 7700

The Nexus 7000 was introduced in 2008. The 7700 appeared in June 2013. These are large rack mount chassis switches that accept between one and sixteen interface cards. Not clear whether this was the initial intent: Nexus 7xxx switches are aimed at the data center while the Catalyst 6500/6800 switches are targetted at the campus.

The Nexus brothers share technology, including ASICs and architecture. But none of the parts from the 7000 work in a 7700 chassis and vice versa. Interface cards in the M series use EARL (Encoded Address Recognition Logic) ASICs. It is mature technology that has been around since the Catalyst 5000. As a side effect, the set of features is pretty rich. Newer ASICs on F series cards go faster but don't yet do as many tricks. F series cards are full on VoQ (virtual output port queuing).

The Nexus 7000 M2 2-port 100 Gb/s interface hashes traffic across ten VQI (virtual queue index) so that parallel lookup engines can dispose of all packets. A single flow always hashes to a single VQI. So any one flow is limited to the VQI capacity -- or 10 Gb/s. The 7000-M2 looks like a 100 Gb/s interface in an environment with a very large count of small flows that hash evenly across all the virtual channels. For the case of a small count of large flows, this design makes poor use of resources. The F3 100 Gb/s card does not have this characteristic.

Cisco gives talks on the Nexus 7xxx at their annual customer meetings. Beyond the buffer sizes listed in the table, it would be difficult to say much in summary that would be better than a link to the source material:

Note that this link is from Ciscolive! Milan, 2014. Newer versions appear every year. Older versions of this talk are available on-line of you want a more focused view of the older cards.