1. A cluster comprising: a first node and a second node, wherein the first node and the second node are configured to cooperatively perform a forwarding service on a first packet, wherein the first node is configured to receive the first packet by using an inbound interface and determine the inbound interface, and wherein the second node is configured to determine an outbound interface and forward the first packet by using the outbound interface of the second node, the outbound interface being determined by the second node according to a forwarding table that is identified by an identifier of the inbound interface and that is corresponding to the forwarding service.