Flashcards in WAN Fundamentals Deck (17):
Leased line service delivers....
bits in both directions, at a predetermined speed, using full-duplex logic
installs a large network of cables and specialized switching devices to create its own computer network
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
Telcos put their equipment in....
Central offices (COs) where they connect cables from COs to buildings where they expect to sell their services
Customer premises equipment includes:
router, serial interface card (within router?), CSU/DSU
CSU/DSU typically provides
the clock rate
The serial cables normally used between a router and external CSU/DSU are called
Data Terminal Equipment (DTE) cables; male cable
DCE cables are....
cables that are female and have the equivalent task of an Ethernet crossover cable
A leased line provides a ________ service
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
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
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
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.
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.
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
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