configuration of etherchannel in AIX

EtherChannelEtherChannel is a network port aggregation technology that allows several Ethernet adapters to be aggregated together to form a virtual Ethernet adapter. The adapters that belong to an EtherChannel are cabled to the same EtherChannel-enabled network switch, which must be manually configured to identify the ports that belong to the EtherChannel.The system sees the EtherChannel as any other Ethernet adapter. For this reason, IP is configured over an EtherChannel adapter as over any Ethernet adapter. Furthermore, all the adapters in the EtherChannel are automatically configured with the same hardware (MAC) address, so they are treated by remote systems as if they were one adapter.EtherChannel's main benefit is that its interface has the aggregated network bandwidth of all its adapters. Traffic is distributed across the adapters in either the standard way (where the adapter over which the packets are sent is chosen depending on the destination address) or on a round-robin basis (where packets are sent evenly across all adapters). If an adapter fails, the packets are automatically sent on the next available adapter in the EtherChannel without disruption to existing user connections. Once the adapter failure has been corrected, the adapter can be used for network traffic once again.In AIX, users can configure multiple EtherChannels per system, but it is required that all the links in one EtherChannel are attached to a single switch. Because the EtherChannel cannot be spread across two switches, the entire EtherChannel is lost if the switch is unplugged or fails. To solve this problem, a new backup option added in AIX 5.2 keeps the service running when the main EtherChannel fails. The backup and EtherChannel adapters should be attached to different network switches. In the event that all of the adapters in the EtherChannel fail, the IP and MAC addresses will be automatically moved to the backup adapter. When any link in the EtherChannel is restored, the service is moved back to the EtherChannel.Network Interface Backup, a mode of operation for EtherChannel, protects against a single point of Ethernet network failure. In Network Interface Backup mode, only one adapter at a time is actively used for network traffic. The EtherChannel tests the currently-active adapter and, optionally, the network path to a user-specified node. When a failure is detected, the MAC and IP addresses are moved to the next adapter, which will be used until it fails. Network Interface Backup provides rapid detection and failover with no disruption to user connections. Network Interface Backup was originally implemented as a mode in the EtherChannel SMIT menu. In AIX 5.2, the backup adapter provides the equivalent function, so the mode was eliminated from the SMIT menu. To use network interface backup in AIX 5.2, see Configure Network Interface Backup.