Page 281 Test Your understanding 2 ·3b ·4acd 5 b 6-26
6-26 • Page 281 • Test Your understanding • 2 • 3 b • 4 a,c,d • 5 b
I Figure 6-3: Points of Presence(POPs) Local Access and Transport Area ( LATA) Other Local area Local Long-Distance POP Carrier 1 Carrier a POP Sw itch E International CarrierⅩ Local Carrier 2 Sw itch Other Country Local Local In the U.s., competing Carrier 1 Carrier 2 carriers connect at Customer Customer points of presence(POPs) 6-27
6-27 Figure 6-3: Points of Presence (POPs) In the U.S., competing carriers connect at points of presence (POPs). Local Access and Transport Area (LATA) Local Carrier 1 Sw itch Local Carrier 2 Sw itch POP Local Carrier 1 Customer Local Carrier 2 Customer Other Local Area Other Country POP Long-Distance Carrier A International Carrier X
Page 282 Test Your understanding ·6b 6-28
6-28 • Page 282 • Test Your understanding • 6 b
I Figure 6-4: Circuit Switching The Pstn has traditionally used circuit sw itching a circuit is an end-to-end connection between two subscribers Capacity is reserved on all trunk lines and sw itches along the w ay 日日 Capacity must be paid for even if it is not used 6-29
6-29 Figure 6-4: Circuit Switching A circuit is an end-to-end connection betw een tw o subscribers. Capacity is reserved on all trunk lines and sw itches along the w ay. Capacity must be paid for even if it is not used. The PSTN has traditionally used circuit sw itching
Figure 6-5: Voice and Data Traffic Full-Duplex(TWo-Way) Circuit Voice traffic. Fairly Constant Use Circuit Switching Is Fairly Eficient Full-Duplex(Two-Way) Circuit Data traffic Short Bursts ong Silences Circuit Switching Is Inefficient The reserved capacity of circuit switching is OK for voice, but not for bursty data transmission 6-30
6-30 Figure 6-5: Voice and Data Traffic Full-Duplex (Two-Way) Circuit Voice Traffic: Fairly Constant Use; Circuit Switching Is Fairly Efficient Data Traffic: Short Bursts, Long Silences; Circuit Switching Is Inefficient Full-Duplex (Two-Way) Circuit The reserved capacity of circuit switching is OK for voice, but not for bursty data transmission