denyingegress server traffic on more than one uplink port at a time. End-host mode is the default Ethernet
switchingmode and should be used if either of the following are used upstream:
• Layer 2 switching for L2 aggregation
• VirtualSwitching System (VSS) aggregation layer
Whenend-host mode is enabled, if a vNIC is hard pinned to an uplink port and this uplink port goes down,
thesystem cannot re-pin the vNIC, and the vNIC remains down.
Note
Switch Mode
Switchmode is the traditional Ethernet switching mode. The fabric interconnect runs STP to avoid loops, and
broadcastand multicast packets are handled in the traditional way. Switch mode is not the default Ethernet
switchingmode, and should be used only if the fabric interconnect is directly connected to a router, or if either
ofthe followingare used upstream:
• Layer 3 aggregation
• VLAN in a box
Forboth Ethernet switching modes, even when vNICs are hard pinned to uplink ports, all server-to-server
unicasttraffic in the server array is sent only through the fabric interconnect and is never sent through
uplinkports. Server-to-server multicast and broadcast traffic is sent through all uplink ports in the same
VLAN.
Note
Configuring Ethernet Switching Mode
Whenyou change the Ethernet switching mode, Cisco UCS Manager logs you out and restarts the fabric
interconnect.For a cluster configuration, Cisco UCS Manager restarts both fabric interconnects sequentially.
Thesecond fabric interconnect can take several minutes to complete the change in Ethernet switching
modeand becomesystem ready. The configuration is retained.
Important
Procedure
Step 1 Inthe Navigation pane, clickthe Equipment tab.
Step 2 Onthe Equipment tab, expand Equipment >Fabric Interconnects >Fabric_Interconnect_Name.
Step 3 Inthe Work pane, click the General tab.
Step 4 Inthe Actions area of theGeneral tab, click one of thefollowing links:
•SetEthernet Switching Mode
•SetEthernet End-Host Mode
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Configuring Ethernet Switching Mode