HIRS Network Subsystem CDMA

HIRS Network Subsystem  CDMA ( HIRS - High-speed Interconnect Router Subsystem)

The system structure of the whole HIRS adopts fast packet switching network based on shared storage (bus type) and hierarchical and modularized structure. A bus type packet switching network is based on two uni-directional buses — CO and DIS buses, which compose the framework of the HIRS network switching platform. The CO bus is contributing bus.

 Under the mediation and control of the U gateway of the NCM module, the NIMs send the data frames received from the RS422 port to the CO bus. After the U gateway receives the data frames from the CO bus, it distributes the data according to the data frame’s destination addresses: to the ATM or DIS bus. The DIS bus (Distribution BUS) is the broadcast distribution bus. Data frames from the directions of both the ATM interface and CO bus are sent to the DIS bus in the broadcast distribution mode under the

control of the U gateway. All the NIMs receive the broadcast data frames from on DIS bus simultaneously, and determine whether to accept the data frame based on the node number of the destination address. For accepted data frames, the NIM will further send the data frames to the corresponding RS422 port according to the port number of the data frame destination address. 

The HIRS network is composed of two HIRS frames. Each HIRS frame contains 22 slots. The two slots in the middle are NCM slots; nine slots at both sides of the NCM slots are for NIMs, and the NIMs at both ends serves as backup. The hardware structure of the HIRS subsystem is shown in Fig.