A packet processing apparatus has an ingress packet processing circuit, an egress packet processing circuit, and a traffic manager. The ingress packet processing circuit processes ingress packets received from ingress ports. The egress packet processing circuit processes egress packets to be forwarded through egress ports. The traffic manager deals with at least packet queuing and scheduling. At least one of the ingress packet processing circuit and the egress packet processing circuit includes a first packet processing unit located at a first packet flow path, and a second packet processing unit located at a second packet flow path. The first packet flow path is parallel with the second packet flow path, and programmability of the first packet processing unit is higher than programmability of the second packet processing unit.