This tutorial is part of the most recent update to Course 101, Chapter 6, October 2008.
After more than 20 years, it appears that an almost universally-accepted standard for mobile radio may finally be implemented, bringing to an end the standards war between carriers that deployed TDMA/GSM for second generation and carriers that deployed CDMA for second generation. Those two factions continued the standards war for the third generation (UMTS and 1X respectively); but now carriers from both of the factions are supporting the GSM/UMTS faction’s Third Generation Partnership Project (3GPP) release 8, known as Universal Terrestrial Radio Access Network Long Term Evolution (LTE). Continue reading “4G Cellular, OFDM and LTE – the "GSM vs. CDMA" Standards War Ends!”
The term soft switch is not defined in a standard… meaning that marketing departments at different equipment and software manufacturers use the same term to describe different things.
A switch, in its simplest form, is a device that causes communications to happen from one point to one other particular point, often when there are multiple “other” points to choose from.
A traditional Central Office (CO) telephone switch might be called a “hard” switch, since it has physical line cards that terminate loops. The switching software running on the computer which is the CO switch directs traffic between a line card and a trunk or between two line cards during a phone call.
The term soft switch is used to mean a computer running switching software that does not have telephone line cards – the communications are instead directed to the correct destination by routers routing packets, a software function.
Continue reading “Soft Switches”