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Flashcards in WAN Fundamentals Deck (17):
1

Leased line service delivers....

bits in both directions, at a predetermined speed, using full-duplex logic

2

Telco ...

installs a large network of cables and specialized switching devices to create its own computer network

3

To create a leased line...

a physical path must exist between the routers on the ends of the link; usually a large and complex network that gives the appearance of a cable between two routers

4

Telcos put their equipment in....

Central offices (COs) where they connect cables from COs to buildings where they expect to sell their services

5

Customer premises equipment includes:

router, serial interface card (within router?), CSU/DSU

6

CSU/DSU typically provides

the clock rate

7

The serial cables normally used between a router and external CSU/DSU are called

Data Terminal Equipment (DTE) cables; male cable

8

DCE cables are....

cables that are female and have the equivalent task of an Ethernet crossover cable

9

A leased line provides a ________ service

Layer 1

10

Two most popular DLL protocols for leased lines

High Level Data Link Control (HDLC) and Point to Point Protocol (PPP)
SN: Organizations create Layer 2 protocols for WAN links

11

Ethernet as a WAN technology basics

The customer connects to an Ethernet link using a router interface.
The fiber leaves the customer building and conncts to some nearby Service Provider location called a point of presence (POP) by using an Ethernet switch

12

Ethernet over MPLS (EoMPLS) provides:

A point-to-point connection between two customer devices
Behavior as if a fiber Ethernet link existed between the two devices
Simply two routers with a single Ethernet link between the two routers; uses Ethernet header and trailer over the WAN link

13

Main idea of WANs

give IP routers a way to forward IP packets from a LAN at one site, over the WAN, and to another LAN at another site.

14

What all three Internet access technologies have in common:

they use a pair of routers: one at the customer side of the WAN link and one at the ISP side.

15

Digital Subscriber LIne (DSL)

Creates a relatively short (miles long, not tens of miles) high speed WAN link between a telco customer and an ISP; utilizes the same single-pair telephone line used for a typical home phone line

16

In order to have DSL service:

You need DSL capable devices such as a DSL modem and the telco has to add DSL equipment at the CO; telco uses a DSL Access Multiplexer (DSLAM) to differentiate data between voice signals and Internet connections via a router

17

Cable Internet

utilizes cable TV cable (CATV) to send data; similar to DSL; both send data faster downstream than upstream; telephone line is replaced with coaxial cable from CATV company and uses a cable modem instead of a DSL