Traffic Classifier, Service Routing Trigger, and Packet Processing Method and System

A packet processing method including a traffic classifier receives a first packet; the traffic classifier determines, in policy information in the traffic classifier and according to a first filtering rule that matches the first packet, a first service identifier that matches the first filtering rule, and an address, which matches the first filtering rule, of a first service routing trigger. The traffic classifier sends a second packet to the first service routing trigger. The policy information includes a filtering rule, an address of a service routing trigger, and a service identifier corresponding to the filtering rule. The filtering rule is used to identify a packet, and the service identifier is used to represent a sequence of a service node that processes the packet. The second packet is formed by adding the first service identifier to the first packet.