A packet sending method, comprising: receiving, by a router, a service packet sent by a user, and acquiring a user identifier and Internet Protocol, IP, 5-tuple information according to the service packet (step 201); the packet sending method being characterized in that it further comprises: determining, in a flow table by the router, a flow group identifier and information about a next-hop service switching entity that are matched with the user identifier and the IP 5-tuple information, wherein the flow table comprises multiple entries, and each entry comprises a user identifier, IP 5-tuple information, a flow group identifier, and information about a next-hop service switching entity, wherein the flow group identifier identifies a flow group and the flow group corresponds to a set of service routing table entries (step 202); and sending, by the router after processing the service packet, a processed service packet to the next-hop service switching entity according to the information about the next-hop service switching entity, wherein the processed service packet comprises the user identifier, the flow group identifier, a router identifier, and a processing result (step 203). receiving, by a router, a service packet sent by a user, and acquiring a user identifier and Internet Protocol, IP, 5-tuple information according to the service packet (step 201); the packet sending method being characterized in that it further comprises: determining, in a flow table by the router, a flow group identifier and information about a next-hop service switching entity that are matched with the user identifier and the IP 5-tuple information, wherein the flow table comprises multiple entries, and each entry comprises a user identifier, IP 5-tuple information, a flow group identifier, and information about a next-hop service switching entity, wherein the flow group identifier identifies a flow group and the flow group corresponds to a set of service routing table entries (step 202); and sending, by the router after processing the service packet, a processed service packet to the next-hop service switching entity according to the information about the next-hop service switching entity, wherein the processed service packet comprises the user identifier, the flow group identifier, a router identifier, and a processing result (step 203). determining, in a flow table by the router, a flow group identifier and information about a next-hop service switching entity that are matched with the user identifier and the IP 5-tuple information, wherein the flow table comprises multiple entries, and each entry comprises a user identifier, IP 5-tuple information, a flow group identifier, and information about a next-hop service switching entity, wherein the flow group identifier identifies a flow group and the flow group corresponds to a set of service routing table entries (step 202); and sending, by the router after processing the service packet, a processed service packet to the next-hop service switching entity according to the information about the next-hop service switching entity, wherein the processed service packet comprises the user identifier, the flow group identifier, a router identifier, and a processing result (step 203).