HUT Comms. Lab, Timo O. Korhonen
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The PSTN (cont.)
nThe 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).
nSupport for data traffic "artificially added" by
nmodems
nISDN (integrated into exchanges)
nxDSL (x digital subscriber line)
nHowever, PSTN is
nEasily congested when subscriber services
(or behavior) changes unexpectedly (no graceful degradation as in CDMA-PLMN): resource wasting