Nexus IO Module has 2 main classification – M & F Series.
M Series:
M1 – 1/10 G
M2 – 10/40/100 G
F Series:
F1 – 1G (L2)
F2 – 10G (L2/L3)
F2E – 10G (L2/L3)
F3 – 40G – Closes feature gap between M & F, with fewer exceptions.
As a rule of thumb, M series is used for L2/L3/L4 with large forwarding table requirements. F Series provides high performance, low latency, low cost & low power with mainly L2 features. F2 & later versions provide more of L3 features.
F1 & F2 requires its own VDC (Virtual Device Context). F2E has the ability to share VDC context with other M & F IO Modules. Recommended good practice is to make sure that each VDC has its own IO Module.
Common M/F Features:
Classic L2/L3
QoS Feature Set
VDC
Security Feature Set
Multicast Feature Set
M-Specific Features:
MPLS, OTV & LISP
F-Specific Features:
Fabricpath & FCoE
In the coming days, the functionality that is unique to M-Series will be replicated on the F-Series. Cisco’s comparison can be found here for Nexus 7000.