Interconnected Network Design

Th pblc swtchd tlphn ntwrk (PSTN) s th ggrgt f th wrld's tlphn ntwrks tht r prtd by ntnl, rgnl, r lcl tlphny prtrs. t prvds nfrstrctr nd srvcs fr pblc tlphny. Th PSTN cnssts f tlphn lns, fbr-ptc cbls, mcrwv trnsmssn lnks, clllr ntwrks, cmmnctns stllts, nd ndrs tlphn cbls ntrcnnctd by swtchng cntrs, sch s cntrl ffcs, ntwrk tndms, nd ntrntnl gtwys, whch llw tlphn srs t cmmnct wth ch thr. rgnlly ntwrk f fxd-ln nlg tlphn systms, th PSTN s nw prdmnntly dgtl n ts cr ntwrk nd nclds trrstrl clllr, stllt, nd lndln systms. Ths ntrcnnctd ntwrks nbl glbl cmmnctn, llwng clls t b md t nd frm nrly ny tlphn wrldwd. Mny f ths ntwrks r prgrssvly trnstnng t ntrnt Prtcl t crry thr tlphny trffc. Th tchncl prtn f th PSTN dhrs t th stndrds ntrntnlly prmlgtd by th T-T. Ths stndrds hv thr rgns n th dvlpmnt f lcl tlphn ntwrks, prmrly n th Bll Systm n th ntd Stts nd n th ntwrks f rpn T mmbrs. Th .164 stndrd prvds sngl glbl ddrss spc n th frm f tlphn nmbrs. Th cmbntn f th ntrcnnctd ntwrks nd glbl tlphn nmbrng pln llws tlphns rnd th wrld t cnnct wth ch thr.