E-100, 7th ed., IEEE New York, 2004. 2. Automatic Protection Switching for SONET, Telcordia Special Report SR-NWT-001756, Issue 1, Piscataway, NJ, Oct. 1990. 3. SONET Dual-Feed Unidirectional Path Switched Ring (UPSR) Equipment Generic Criteria, Tel- cordia GR-1400, Issue 2, Piscataway, NJ, Jan. 1999. 4. SONET Bidirectional Line-Switched Ring Equipment Generic Criteria, Telcordia GR-1230- CORE, Issue 4, Piscataway, NJ, Dec. 1998. 5. Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, ANSI/IEEE Std 802.11, 1999 edition, IEEE, New York, 1999. 6. Specific Requirements Part 15.1: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Wireless Personal Area Networks (WPANs(TM)), IEEE 802.15, IEEE New York, 2002. 7. Part 16: Air Interface for Fixed Broadband Wireless Access Systems, IEEE 802.16, IEEE New York, 2001. CCITT SIGNALING SYSTEM NO. 7 14.1 INTRODUCTION CCITT Signaling System No. 7 (SS No. 7) was developed to meet the stringent signaling requirements of the all-digital network based on the 64-kbps channel. It operates in quite a different manner than the signaling discussed in Chapter 7. Nevertheless, it must provide supervision of circuits and address signaling and must also carry call progress signals and alerting notification to be eventually passed to the called subscriber. These requirements certainly look familiar and are no different from the ones discussed in Chapter 7. The difference is in how it is done. CCITT No. 7 is a data network entirely dedicated to interswitch signaling.¹ Simply put, CCITT SS No. 7 is described as an international standardized general- purpose common-channel signaling system that: Is optimized for operation with digital networks where switches used stored-program control (SPC), such as the DMS-100 series switches and the 5ESS, among others, which were discussed in Section 6.11. Can meet present and future requirements of information transfer for interprocessor transactions with digital communications networks for