The PSTN (cont.)
			n The PSTN is optimized for fixed speech service, statistically distributed, analog subscribers (by using the circuit switching technology that was made available beginning of this century). n Support for data traffic "artificially added" by n modems n ISDN (integrated into exchanges) n xDSL (x digital subscriber line) n However, PSTN is n Easily congested when subscriber services (or behavior) changes unexpectedly (no graceful degradation as in CDMA-PLMN): resource wasting