Appendix 6: Inter-PABX Signalling
Richard J. Manterfield · Institution of Engineering and Technology eBooks · 1999
As mentioned in Chapter 13, private network signalling systems evolved to take advantage of the feature-rich nature of PABXs before the advent of virtual private networks (VPNs). A successful system was the Digital Private Network Signalling System (DPNSS). This appendix gives a brief outline of such a private network signalling system. The system is based on three layers, similar to those of DSS1. This appendix focuses on the Layer 3 aspects.