Cisco 7206 Network Configuration Guide - Page 166

Information About Port Channels Chapter 6 Configuring Port Channels Send document comments to [email protected] Table 6-1 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 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 displays 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. The default port-channel mode is on. 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 if 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. • A port in passive mode cannot form a port channel with another port that is also in passive mode, because neither port will initiate negotiation. • A port in on mode is not running LACP and cannot form a port channel with another port that is in active or passive mode. LACP ID Parameters This section describes the LACP parameters in the following topics: • LACP System Priority, page 6-10 • LACP Port Priority, page 6-11 • LACP Administrative Key, page 6-11 LACP System Priority Each system that runs LACP has an LACP system priority value. You can accept the default value of 32768 for this parameter, or you can configure a value between 1 and 65535. LACP uses the system priority with the MAC address to form the system ID and also uses the system priority during negotiation with other devices. A higher system priority value means a lower priority. The system ID is different for each VDC. 6-10 Cisco Nexus 7000 Series NX-OS Interfaces Configuration Guide, Release 5.x OL-23435-03