Cisco Nexus 2000 Series Manual page 12

Guidelines and Limitations for the Fabric Extender
• You must enable the Fabric Extender feature set in the default virtual device context (VDC). After you
enable the feature set in the default VDC, the FEX can belong to any VDC and can be configured from
those VDCs.
• All the uplinks and host ports of a Fabric Extender belong to a single VDC. The ports cannot be allocated
or split among multiple VDCs.
• You must connect the Fabric Extender to its parent Cisco Nexus 7000 Series device with a 32-port
10-Gigabit M1 module (N7K-M132XP-12), a 32-port, 10-Gigabit M1-XL module (N7K-M132XP-12L),
an M2-Series module, or an F2-Series module.
• The Fabric Extender feature set operation might cause the standby supervisor to reload if it is in an
unstable state, such as following a service failure or powering up. You can check whether the standby
supervisor is stable by using the show modules command. When the standby supervisor is stable, it is
indicated as ha-standby.
• You can configure the Fabric Extender host interfaces as edge ports only. The interface is placed in an
error-disabled state if a downstream switch is detected.
• The Fabric Extender does not support PVLANs.
• For Cisco NX-OS Release 6.2(2) and later releases, the FEX supports queuing, which allows a router
to be connected to a Layer 3 FEX interface or a router to be connected to a Layer 2 FEX interface (using
SVI).
Follow these guidelines for a router that is connected to a Layer 2 FEX interface (using SVI):
• For Cisco NX-OS Release 6.2(2) and later releases, the Cisco Fabric Extender supports routing protocol
adjacency. Before Cisco NX-OS Release 6.2(2), the Fabric Extender cannot participate in a routing
protocol adjacency with a device attached to its port. Only a static direct route is supported. This restriction
applies to both of the following supported connectivity cases:
• For Cisco NX-OS Release 6.2(2) and later releases, the Cisco Fabric Extender supports the following:
• For Cisco NX-OS Release 6.2(2) and later releases, the Cisco Fabric Extender supports optimized
multicast flooding (OMF) is available on FEX ports.
• The Cisco Fabric Extender does not support policy based routing (PBR).
Cisco Nexus 2000 Series NX-OS Fabric Extender Software Configuration Guide for Cisco Nexus 7000 Series
Switches, Release 5.2
12
• You can configure routing adjacency with Layer 3 on the peer router.
• You can configure routing adjacency with SVI on the router using access/trunk interfaces.
Note FEX interfaces do not support the spanning tree protocol.
You must configure the network without the possibility of any loops.
• An SVI with a FEX single port or portchannel in Layer 2 mode.
• A FEX port or portchannel in Layer 3 mode.
◦ Queuing for Ethernet frames on a FEX-based CoS and DSCP values and support for queuing Fibre
Channel over Ethernet (FCoE) frames on a FEX.
◦ FEX HIF (FEX Host Interface) port to connect to a Protocol Independent Multicast (PIM) router.
Overview