networking - Why does the number of links not matter in the transmission time of circuit switching? -


i reading book networking, , says that, in circuit switching environment, number of links , switches signal has go through before getting destination not affect overall time takes signal received. on other hand, in packet switching scenario number of links , switches make difference. spent quite bit of time trying figure out, can't seem it. why that?

to drastically over-simplify, circuit-switched environment has direct line transmitter transmitted once connection has been established; imagine old-fashioned phone-call going through switchboards. therefore transmission time same regardless of hops (well, ignoring physical time takes signal move on wire, small since it's moving @ speed of light).

in packet-switched environment, there no direct connection. packet of data sent transmitter first hop, tries calculate open route destination. passes data onto next hop, again has calculate next available hop, , on. takes time linearly increases number of hops. think sending letter through postal system. has go house post office, post office local distribution center, local distribution center national one, recipient's local distribution center, recipient's post office, house.

the difference 1 connection @ time per circuit can exist on circuit-switched network; again, think phone line using make call. whereas in packet switched network many transmitters , receivers can sending data @ same time; again, think many people sending/recieving letters.


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