Cisco Nexus 5000 Series Switch CLI Software Configuration Guide, NX-OS 4.0(1a)N1 (OL-16597-01, January 2009)

Send feedback to [e-mail]
11-2
Cisco Nexus 5000 Series Switch CLI Software Configuration Guide
OL-16597-01
Chapter 11 Configuring Port Channels
Information About Port Channels
You can collect up to eight ports into a static port channel or you can enable the Link Aggregation
Control Protocol (LACP). Configuring port channels with LACP requires slightly different steps than
configuring static port channels (see the “Configuring Port Channels” section on page 11-7).
Note Cisco NX-OS does not support Port Aggregation Protocol (PAgP) for port channels.
A port channel bundles individual links into a channel group to create a single logical link that provides
the aggregate bandwidth of up to eight physical links. If a member port within a port channel fails, traffic
previously carried over the failed link switches to the remaining member ports within the port channel.
Each port can be in only one port channel. All the ports in a port channel must be compatible; they must
use the same speed and operate in full-duplex mode (see the “Compatibility Requirements” section on
page 11-2). When you are running static port channels, without LACP, the individual links are all in the
on channel mode; you cannot change this mode without enabling LACP (see the “Port-Channel Modes”
section on page 11-6).
Note You cannot change the mode from ON to Active or from ON to Passive.
You can create a port channel directly by creating the port-channel interface, or you can create a channel
group that acts to aggregate individual ports into a bundle. When you associate an interface with a
channel group, Cisco NX-OS creates a matching port channel automatically if the port channel does not
already exist. You can also create the port channel first. In this instance, Cisco NX-OS creates an empty
channel group with the same channel number as the port channel and takes the default configuration.
Note The port channel is operationally up when at least one of the member ports is up and that port’s status is
channeling. The port channel is operationally down when all member ports are operationally down.
Compatibility Requirements
When you add an interface to a channel group, Cisco NX-OS checks certain interface attributes to ensure
that the interface is compatible with the channel group. Cisco NX-OS also checks a number of
operational attributes for an interface before allowing that interface to participate in the port-channel
aggregation.
The compatibility check includes the following operational attributes:
• Port mode
• Access VLAN
• Trunk native VLAN
• Allowed VLAN list
• Speed
• 802.3x flow control setting
• MTU
The Cisco Nexus 5000 Series switch only supports system level MTU. This attribute cannot be
changed on an individual port basis.
• Broadcast/Unicast/Multicast Storm Control setting