The new types of digital lines installed by the carriers began to form a new physical carrier services network. The lines did not cross-connect or inter- sect with any of the millions of circuit-switched lines that are in place and continue to be installed by the carriers. At the carrier company’s facilities, newer types of fully digital equipment terminated these digital lines.
This new carrier services network was called the digital services carrier net- work. (It is also known as the digital signal carrier network, or simply as the DS.) This network used higher-bandwidth digital lines and operated with packet-switched protocols to network computer data. (For more on proto- cols, which are simply rules for using the network, see Chapter 1.)
Soon thereafter, the DS network was defined based on its fundamental unit of bandwidth, known as the channel. The smallest channel unit provided a bandwidth of 64 Kbps (64 thousand bits per second). This channel was called a DS0, pronounced “D–S–zero.” (Many computer gurus start counting with 0; it’s a binary thing.) DS0 became the base unit of bandwidth from which other dedicated transports were defined. (In Chapter 7, I cover the popular DS stan- dards in detail.)
The DS network also introduced to the telecommunications vocabulary another term that characterizes most of the transport mechanisms that are not part of the older circuit-switched network. Because the lines used by the DS carriers were installed between private customer locations and the public at large could not use or connect to them, DS lines became known as dedi- cated to the customer leasing them. The entire series of DS standards eventu- ally became known as the dedicated carrier services network.
This new carrier services network was called the digital services carrier net- work. (It is also known as the digital signal carrier network, or simply as the DS.) This network used higher-bandwidth digital lines and operated with packet-switched protocols to network computer data. (For more on proto- cols, which are simply rules for using the network, see Chapter 1.)
Soon thereafter, the DS network was defined based on its fundamental unit of bandwidth, known as the channel. The smallest channel unit provided a bandwidth of 64 Kbps (64 thousand bits per second). This channel was called a DS0, pronounced “D–S–zero.” (Many computer gurus start counting with 0; it’s a binary thing.) DS0 became the base unit of bandwidth from which other dedicated transports were defined. (In Chapter 7, I cover the popular DS stan- dards in detail.)
The DS network also introduced to the telecommunications vocabulary another term that characterizes most of the transport mechanisms that are not part of the older circuit-switched network. Because the lines used by the DS carriers were installed between private customer locations and the public at large could not use or connect to them, DS lines became known as dedi- cated to the customer leasing them. The entire series of DS standards eventu- ally became known as the dedicated carrier services network.
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