HP Cisco Nexus 5000 Cisco Nexus 5000 Series Switch CLI Software Configuration - Page 206

Information About Port Channels Chapter 11 Configuring Port Channels Send feedback to [email protected] higher port priority value means a lower priority for LACP. You can configure the port priority so that specified ports have a lower priority for LACP and are most likely to be chosen as active links, rather than hot-standby links. • LACP administrative key-LACP automatically configures an administrative key value equal to the channel-group number on each port configured to use LACP. The administrative key defines the ability of a port to aggregate with other ports. A port's ability to aggregate with other ports is determined by these factors: - Port physical characteristics, such as the data rate, the duplex capability, and the point-to-point or shared medium state - Configuration restrictions that you establish Port-Channel Modes Individual interfaces in port channels are configured with channel modes. When you run static port channels, with no protocol, the channel mode is always set to on. After you enable LACP globally on the device, you enable LACP for each channel by setting the channel mode for each interface to active or passive. You can configure either channel mode for individual links in the LACP channel group. Note You must enable LACP globally before you can configure an interface in either the active or passive channel mode. Table 11-2 describes the channel modes. Table 11-2 Channel Modes for Individual Links in a Port Channel Channel Mode passive active on Description LACP mode that places a port into a passive negotiating state, in which the port responds to LACP packets that it receives but does not initiate LACP negotiation. LACP mode that places a port into an active negotiating state, in which the port initiates negotiations with other ports by sending LACP packets. All static port channels, that is, that are not running LACP, remain in this mode. If you attempt to change the channel mode to active or passive before enabling LACP, the device returns an error message. You enable LACP on each channel by configuring the interface in that channel for the channel mode as either active or passive. When an LACP attempts to negotiate with an interface in the on state, it does not receive any LACP packets and becomes an individual link with that interface; it does not join the LACP channel group. Both the passive and active modes allow LACP to negotiate between ports to determine if they can form a port channel, based on criteria such as the port speed and the trunking state. The passive mode is useful when you do not know whether the remote system, or partner, supports LACP. Ports can form an LACP port channel when they are in different LACP modes as long as the modes are compatible as in the following examples: • A port in active mode can form a port channel successfully with another port that is in active mode. • A port in active mode can form a port channel with another port in passive mode. 11-6 Cisco Nexus 5000 Series Switch CLI Software Configuration Guide OL-16597-01