Boards

The boards of the SE2600 consist of the SRU, SFU, SPU, and LPU.
The SRU is the core board for system management.
The SFU interchanges service data of the entire system.
The SPU provides all service processing functions.
The LPU provides physical interfaces to external network elements (NEs) or external networks. 

SRU
The SRUs control and manage the system in a centralized manner and they work in 1+1 backup mode. functioning as the clock source and the management and maintenance unit of the system, the SRUs provide the functions of the control plane and the system maintenance plane. The SRU is composed of the MPU and SFU modules. The two SFU modules on the two SRUs work in load-sharing mode.
SFU
The SFUs support quick data exchange. Working in load-sharing mode, the SFUs can support line-rate switching of 640 Gbit/s (160 Gbit/s x 4) traffic.The SE2600 is equipped with two independent SFUs modules located on the two SRUs.
SPU
The SPUs are service control boards for providing functions such as signaling dispatching, B2BUA, P-CSCF, media processing, security IP and signaling layers, session-based QoS. The SPUs adopt the multi-core CPU technology so that the SE2600 can flexibly meet various requirements. The SPUs work in 1+1 master/slave mode.
LPU
The LPU provides physical interfaces to external networks. The interfaces include:
10GE optical interface
GE electrical interface 

GE optical interface
The LPU is composed of the LPU module, fabric adaptor (FAD) for the switching network,and physical interface card (PIC).The three modules work together to process and forward service data quickly, and maintain and manage link protocols and forwarding information base (FIB) tables.