Stored Program Controlled Network: CCIS and SPC Network Performance

Abstract

Common-channel interoffice signaling (CCIS) represents a major advance in interoffice signaling speed and capability over current inband signaling systems. The introduction of CCIS between Stored Program Control (SPC) switching offices is reducing ineffective machine attempts (IMAS) caused by transmission and switching irregularities associated with inband signaling. Because signaling between CCIS-equipped switching offices is concentrated in a relatively small number of signaling links and signal transfer points (STPS), a high standard of performance for the signaling network is essential. Therefore, the design of the signaling network incorporates many features to assure a high degree of availability. Cumulative data on STPS and studies of signaling links are the principal measures of signaling network performance. Data on their performance are presented that confirm the high availability of the signaling network.