Linking a chassis to two fabric-port-channel port groups does not affect the VIF namespace unless it is
manually acknowledged. The VIF namespace is then automatically set to the smaller size fabric port-channel
port group usage (either 63 or 118 VIFs) of the two groups.
Caution
For high availability cluster-mode applications, we strongly recommend symmetric cabling configurations.
If the cabling is asymmetric, the maximum number of VIFs available is the smaller of the two cabling
configurations.
For more information on the maximum number of VIFs for your Cisco UCS environment, see the Configuration
Limits document for your hardware and software configuration.
Proper FEX and Fabric Interconnect Port Connectivity
The following illustrations are for example only; you do not need to skip available ports to provide future
expansion room. See the UCS Manager configuration guide for FI port configuration considerations and
limitations.
Note
Observe the following guidelines:
•
When you connect the server chassis to the fabric interconnect, do not connect the FEXes to the fabric
interconnect
’
s expansion modules. While similar in appearance to the other ports on the fabric interconnect,
the expansion modules are never used for direct chassis connections. They are typically used for SAN
connectivity or network uplink.
•
All ports of a FEX must be connected to only one fabric interconnect. You must connect each fabric
interconnect to the chassis through its own FEX.
•
If you need to connect to a second fabric interconnect, do the following:
◦
The chassis must have a second FEX installed.
◦
All ports of the second FEX must be connected to the second fabric interconnect only because the
FEX is a fabric extender, which can only be connected to a single switch, or in this case, a fabric
interconnect.
Cisco UCS 5108 Server Chassis Installation Guide
59
Installation
Proper FEX and Fabric Interconnect Port Connectivity
