HP Cisco Catalyst Blade Switch 3020 Cisco Catalyst Blade Switch 3020 for HP So - Page 609

Chapter 28 Configuring EtherChannels and Layer 2 Trunk Failover Configuring EtherChannels Step 4 Step 5 Command show etherchannel load-balance copy running-config startup-config Purpose Verify your entries. (Optional) Save your entries in the configuration file. To return EtherChannel load balancing to the default configuration, use the no port-channel load-balance global configuration command. Configuring the PAgP Learn Method and Priority Network devices are classified as PAgP physical learners or aggregate-port learners. A device is a physical learner if it learns addresses by physical ports and directs transmissions based on that knowledge. A device is an aggregate-port learner if it learns addresses by aggregate (logical) ports. The learn method must be configured the same at both ends of the link. When a device and its partner are both aggregate-port learners, they learn the address on the logical port-channel. The device sends packets to the source by using any of the ports in the EtherChannel. With aggregate-port learning, it is not important on which physical port the packet arrives. PAgP cannot automatically detect when the partner device is a physical learner and when the local device is an aggregate-port learner. Therefore, you must manually set the learning method on the local device to learn addresses by physical ports. You also must set the load-distribution method to source-based distribution, so that any given source MAC address is always sent on the same physical port. You also can configure a single port within the group for all transmissions and use other ports for hot standby. The unused ports in the group can be swapped into operation in just a few seconds if the selected single port loses hardware-signal detection. You can configure which port is always selected for packet transmission by changing its priority with the pagp port-priority interface configuration command. The higher the priority, the more likely that the port will be selected. Note The switch supports address learning only on aggregate ports even though the physical-port keyword is provided in the CLI. The pagp learn-method command and the pagp port-priority command have no effect on the switch hardware, but they are required for PAgP interoperability with devices that only support address learning by physical ports. When the link partner of the Cisco Catalyst Blade Switch 3020 for HP is a physical learner (such as a Catalyst 1900 series switch), we recommend that you configure the Cisco Catalyst Blade Switch 3020 for HP as a physical-port learner by using the pagp learn-method physical-port interface configuration command. Set the load-distribution method based on the source MAC address by using the port-channel load-balance src-mac global configuration command. The switch then sends packets to the Catalyst 1900 switch using the same port in the EtherChannel from which it learned the source address. Only use the pagp learn-method command in this situation. OL-8915-01 Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide 28-13