Reference Guide
Interfaces | 133
Port channels can contain a mix of 100, 1000, or 10000 Mbps Ethernet interfaces and TenGigabit Ethernet
interfaces. The interface speed (100, 1000, or 10000 Mbps) used by the port channel is determined by the
first port channel member that is physically up. FTOS disables the interfaces that do not match the
interface speed set by the first channel member. That first interface may be the first interface that is
physically brought up or was physically operating when interfaces were added to the port channel. For
example, if the first operational interface in the port channel is a TenGigabit Ethernet interface, all
interfaces at 1000 Mbps are kept up, and all 100/1000/10000 interfaces that are not set to 1000 Mbps speed
or auto negotiate are disabled.
1GbE and 10GbE Interfaces in Port Channels
When both Gigabit and TenGigabitEthernet interfaces are added to a port channel, the interfaces must
share a common speed. When interfaces have a configured speed different from the port channel speed, the
software disables those interfaces.
The common speed is determined when the port channel is first enabled. At that time, the software checks
the first interface listed in the port channel configuration. If that interface is enabled, its speed
configuration becomes the common speed of the port channel. If the other interfaces configured in that port
channel are configured with a different speed, FTOS disables them.
For example, if four interfaces (TenGig 0/0, 0/1, 0/2, 0/3) in which TenGig 0/0 and TenGig 0/3 are set to
speed 100 Mb/s and the others are set to 1000 Mb/s, with all interfaces enabled, and you add them to a port
channel by entering
channel-member tengigabitethernet 0/0-3 while in port channel interface mode, and FTOS
determines if the first interface specified (TenGig 0/0) is up. After it is up, the common speed of the port
channel is 100 Mb/s. FTOS disables those interfaces configured with speed 1000 Mb/s or whose speed is
1000 Mb/s as a result of auto-negotiation.
In this example, you can change the common speed of the port channel by changing its configuration so the
first enabled interface referenced in the configuration is a 1000 Mb/s speed interface. You can also change
the common speed of the port channel by setting the speed of the TenGig 0/0 interface to 1000 Mb/s.
Uplink Port Channel: VLAN Membership
The tagged VLAN membership of the uplink LAG is automatically configured based on the VLAN
configuration of all server-facing ports (ports 1 to 32).
The untagged VLAN used for the uplink LAG is always the default VLAN 1.
Server-Facing Port Channel: VLAN Membership
The tagged VLAN membership of a server-facing LAG is automatically configured based on the
server-facing ports that are members of the LAG.
The untagged VLAN of a server-facing LAG is auto-configured based on the untagged VLAN to which
the lowest numbered server-facing port in the LAG belongs.