Chapter 16 Flashcards
are communications networks that cover broad geographic areas that still frequently use phone companies (service providers) along with their circuit-switched networks to connect LANs together. p576
WANs
WAN service type from a provider typically use: p577
Customer premises equipment (CPE) Channel service unit/data service unit (CSU/DSU) Demarcation point Smart Jack/NIU Copper Line Drivers/Repeaters Local loop Central office (CO) Toll network
is a Layer 1 device that connects your serial ports on your router to the provider’s network and connects directly to the demarcation point (demark) or location. p577
Channel service unit/data service unit (CSU/DSU)
What is a Demarcation point p578
The demarc is the precise spot where the service provider’s (local exchange carrier) responsibility ends and the CPE begins. It’s generally a device in a telecommunications closet owned and installed by the telecommunications company (telco).
What is a Local loop. p579
A cable consisting of a pair of copper wires called the local loop connects the demarc to the closest switching office known as a central office (CO).
What is a Central office (CO).p 579
A phone company building that connects the customer’s network to the provider’s switching network. Good to know is that a CO is sometimes referred to as a point of presence (POP).
What is a Toll network. p579
The toll network is a trunk line inside a WAN provider’s network. This network is a collection of switches and facilities owned by the ISP.
The portion of the PSTN that runs from your house to the rest of the world is known as. p579
plain old telephone service (POTS)
Two key concepts to keep in mind about PSTN are. p579
public and switched
basically means that, for a fee, anyone can lease the use of the network without having to deal with running any cabling. p579
Public
is a pre-established WAN communications path that goes from the CPE through the DCE switch and then over to the CPE of the remote site. p580
dedicated leased line
uses dial-up modems or ISDN and is used for low-bandwidth data transfers. p581
Circuit switching
can be thought of as a network that’s designed to look like a leased line yet charges you more like circuit switching does. p581
Packet switching
What are some WAN connection types. p580-81
Packet switching
Circuit switching
dedicated leased line
Modems are required to _______________ the signal, which means translating the analog signal our ears hear into a digital stream for transfer across a digital network. p582
modulate/demodulate
