Information About Using a Fabric Extender with a Cisco Nexus 7000 Series Switch
You can extend the Cisco Nexus 7000 Series switch architecture by connecting
up to 32 FEXs as remote I/O modules. Depending on which FEX model that you connect to the switch, the FEX provides top-of-the-rack connectivity for up to 48, 32, or 24 hosts, and it becomes an extension of the parent Cisco Nexus 7000 Series switch fabric, with the FEX and the switch becoming a virtual modular system. The FEX forwards all 100/1000 Ethernet or 1- and 10-Gigabit Ethernet traffic from the hosts to the switch over 10-Gbps uplinks. Traffic flows from the switch to the FEX over the 10-Gbps uplinks and to the individual hosts over 100/1000 Ethernet or 1- and 10-Gigabit Ethernet downlinks.
You connect a FEX uplink port to the Cisco Nexus 7000 Series switch through one of the following Ethernet I/O modules installed in the switch:
•F2 Series 48-port 1 or 10-Gigabit Ethernet I/O module (N7K-F248XP-25)
•M1 Series 32-port 10-Gigabit Ethernet I/O module (N7K-M132XP-12)
•M1 Series 32-port 10-Gigabit Ethernet I/O module with XL option (N7K-M132XP-12L)
•M2 Series 24-port 10-Gigabit Ethernet I/O module (N7K-M224XP-23L)
http://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus2000/hw/installation/guide/nexus_2000_hig/overviewN7K.html
