Subsystem 1 h 上海充通 Subsystem 2 SHANGHAI JIAO TONG Layer 2 Layer 1 Layer 3 Layer 2 Layer 4 Layer 3 Application Layer Application Layer Presentation Layer Presentation Layer Session Layer Session Layer Bidirectional associa-tions for each layer Transport Layer Transport Layer Network Layer Network Layer Data Link Layer Data Link Layer Hardware Hardware Processor 1 Processor 2 Software EngineeringSoftware Engineering Application Layer Presentation Layer Session Layer Transport Layer Network Layer Data Link Layer Hardware Bidirectional associa- tions for each layer Presentation Layer Session Layer Transport Layer Network Layer Data Link Layer Hardware Application Layer Layer 1 Layer 2 Layer 3 Layer 4 Subsystem 1 Processor 1 Processor 2 Layer 1 Layer 2 Layer 3 Subsystem 2