Chapter 4 - Fundamentals of WANs

In practice, the clocking concept includes a _______ of different clock sources

hierarchy

DCE

Data Communications Equipment

DTE

Data Terminal Equipment

CSU/DSU

Channel Service Unit / Data Service Unit

The device that provides clocking is referred to as the (DCE/DTE)?

DCE

The device that receives clocking is referred to as the (DCE/DTE)?

DTE

Today, most telcos offer leased lines in multiples of __kbps

64

Speed of DS0

64kbps

Speed of DS1

1.544 Mbps

DS1 is also known as ______

T1

Speed of T1

1.544 Mbps

Speed of DS3

44.736 Mbps

DS3 is also known as _____

T3

Speed of T3

44.736 Mbps

The two most popular data link layer protocols used on point-to-point links are?

HDLC and PPP

The address field in HDLC is usually un-necessary becuase?

In a point-to-point link, there can only be one possible recipient for the frame.

The proprietary Cisco HDLC frame adds what field?

Type

The Address field in HDLC was useful in the past, when the telco would sell ________

multidrop circuits

T/F: Cisco uses the same values in its 2-byte HDLC Protocol Type field as it does in the Ethernet Protocol Type field

True

T/F: The PPP frame looks identical to the Cisco proprietary HDLC frame

True

For a Frame Relay service, a leased line is installed between each router and a nearby Frame Relay switch. These lines are called ______

access links

The address field used by Frame Relay is called _______

DLCI

DLCI

Data Link Connection Identifier

The Frame Relay header and trailer are defined by a protocol called _________

Link Access Procedure - Frame

LAPF

Link Access Procedure - Frame

The logical path that a frame travels between each pair of routers in a Frame Relay system is called a _______

Virtual Circuit

T/F: CIR represents the maximum data rate over a particular VC

False

CIR

Committed Information Rate

T/F: CIR represents a minimum data rate over a particular VC. The actual maximum data rate is usually higher.

True