HUT Comms.
Lab, Timo O. Korhonen
31
The PSTN (cont.)
nThe PSTN is optimized for statistically distributed, analog speech
subscribers (by using the circuit switching technology
that was available beginning of this century).
nSupport for data traffic "artificially added" by
nmodems
nISDN (integrated into exchanges)
nxDSL (asynchronous digital subscriber line)
nHowever, PSTN is
nEasily congested when subscriber behavior
changes unexpectedly (no graceful degradation as in
CDMA-PLMN): resource wasting