nclusion SS7 is used by the PSTN to increase the speed and efficiency of the network by trans- porting the network's signaling needs over a separate data network. It is designed for high reliability through redundancy. The use of a separate signaling network provides the op- portunity to look at and manipulate the signaling information. This capability makes pos- sible number translation services, such as 1-800 and 1-900 services, and support for LNP. Users of the PSTN can subscribe to services that provide the ability to connect to the SS7 network and to make local decisions as to where calls such as 1-800 numbers are to be routed on a call-by-call basis. This service is particularly useful for balancing call volumes across PBX-based call centers and, more generally, for redirecting calls to where the party being called can be found. Superscript(3) One of the authors (Rosenberg) tends to think like an engineer from the bottom up. Rosenberg would say that the two very different physical models are represented by the same logical model. Kemp, thinking as a planner from the top down, would say that one logical model has two very different physical implementations. The use of the distinction between logical and physical mod- els can help team members who think very differently create networks (or books) as a team. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Source: CDMA CAPACITY AND QUALITY OPTIMIZATION Chapter ANSI-41 The second-generation (2G) wireless world is divided into two camps, the Global Sys- tem for Mobility (GSM), which does not use ANSI-41, and everybody else, who does. GSM has its own mobile application part (GSM MAP) for its signaling protocol. Other companies proposed Interim Standard 41 (IS-41), which then became the American Na- tional Standards Institute's ANSI-41 standard in use today. It may seem odd that an American st