When a CB device receives through a first port a packet sent from a PE device, the CB device analyzes a unique identifier of the PE device from the packet. If the first port is not included in any of aggregation groups, an array table is queried. If the unique identifier of the PE device does not exist in the array table, an idle first aggregation group identifier is selected, a first aggregation group corresponding to the first aggregation group identifier is created, the first port is added to the first aggregation group, and a correspondence between the first aggregation group identifier and the unique identifier of the PE device is recorded in the array table.