thatis specifically assigned to that VLAN, and is selectivelyexcluded from all other uplink ports and port
channels.However, traffic for VLANs that are not specifically assigned to an uplink Ethernet port or port
channelcan still travel on all uplink ports or port channels, includingthose thatcarry traffic for the disjoint
L2networks.
InCisco UCS, the VLAN represents the upstream disjoint L2 network. When you design your network
topologyfor disjoint L2 networks, you mustassign uplink interfaces to VLANs not the reverse.
Forinformation about the maximum number of supported upstream disjoint L2 networks, see Cisco UCS
6100and 6200 Series Configuration Limits for Cisco UCS Manager, Release 2.0.
Guidelines for Configuring Upstream Disjoint L2 Networks
Whenyou plan your configurationfor upstream disjoint L2 networks, consider the following:
Ethernet Switching Mode Must Be End-Host Mode
CiscoUCS only supports disjoint L2 networks when the Ethernet switching mode of the fabric interconnects
isconfigured for end-host mode. Youcannot connect to disjoint L2 networks if the Ethernet switching mode
ofthe fabricinterconnects is switchmode.
Symmetrical Configuration Is Recommended for High Availability
Ifa Cisco UCS domain is configured for high availabilitywith two fabric interconnects, we recommend that
bothfabric interconnects are configured with the same set of VLANs.
VLAN Validity Criteria Are the Same for Uplink Ethernet Ports and Port Channels
TheVLAN used for the disjoint L2 networks must be configured and assigned to an uplink Ethernet port or
uplinkEthernet port channel. If the port or port channel does not include the VLAN, Cisco UCS Manager
considersthe VLAN invalid and does the following:
• Displays a configuration warning in the Status Details area for the server.
• Ignores the configuration for the port or port channel and drops all traffic for that VLAN.
Thevalidity criteria are the same for uplink Ethernet ports and uplinkEthernet port channels. Cisco UCS
Managerdoes notdifferentiate between the two.
Note
Overlapping VLANs Are Not Supported
CiscoUCS does not support overlapping VLANs in disjoint L2 networks. You must ensure that each VLAN
onlyconnects to one upstream disjoint L2 domain.
Each vNIC Can Only Communicate with One Disjoint L2 Network
AvNIC can only communicate with one disjoint L2network. If a server needs to communicate with multiple
disjointL2 networks, you mustconfigure a vNICfor eachof thosenetworks.
Tocommunicate with more than two disjoint L2 networks, a server must have a Cisco VIC adapter that
supportsmore than two vNICs.
Cisco UCS Manager GUI Configuration Guide, Release 2.0
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Guidelines for Configuring Upstream Disjoint L2 Networks