Chapter 3

Question 1

SOHO

Answer 1

Small Office Home Office

Question 2

Leased Line

Answer 2

Leased Line service delivers bits in both directions, at a predetermined speed, using full-duplex logic. Leased line uses two pairs of wires, one pair for each direction of sending data, which allows full-duplex operation.

Question 3

Leased circuit, Circuit

Answer 3

The word line and circuit are often used as synonyms in telco terminology; circuit makes reference to the electrical circuit between the two endpoints

Question 4

Serial Link, Serial Line

Answer 4

The words link and line are also often used as synonyms. Serial in this case refers to the fact that the bits flow serially, and that routers use serial interfaces

Question 5

Point-to-point link, Point-to-point Line

Answer 5

Refers to the fact that the topology stretches between two points, and two points only. (Some older leased lines allowed more than two devices)

Question 6

T1

Answer 6

A specific type of leased line that transmits data at 1.544 megabits per second (1.544 Mbps)

Question 7

WAN link, Link

Answer 7

Both these terms are very general, with no reference to any specific technology

Question 8

Private Line

Answer 8

Refers to the fact that the data sent over the line cannot be copied by other telco customers, so the data is private

Question 9

CSU/DSU

Answer 9

Channel Service Unit/ Data Service Unit

Question 10

How does one site communicate with another site using a Leased Line?

Answer 10

For each site there will be a Customer Premises equipment (CPE), which includes the router, serial interface card, and CSU/DSU. Each router uses a serial interface card that acts somewhat line and Ethernet NIC, sending and recieving data over the physical link. The physcial link requires a function called a channel service unit/ data service unit (CSU/DSU). The CSU/DSU can either be intergrated into the serial interface card in the router or sit outside the router as an external device.