2.5 WAN technologies

Question 1

What do dashed lines represent in WAN topology?

Answer 1

Virtual circuits.

Question 2

What is frame relay?

Answer 2

WAN packet switching technology, encapsulates data in labelled frames and puts it in frame relay cloud.
Leaves error correcting up to end user.
Replaced by MPLS.

Question 3

What commonly uses frame relay?

Answer 3

ISDN

Question 4

Which is better frame relay or ATM?

Answer 4

ATM

Question 5

What is BRI?

Answer 5

Basic Rate Interface (2B+D);
One of the two delivery method for ISDN, used for smaller connections.
Two 64 kbps bearer channels (B) for data, One 16kbps signaling channel (D).

Question 6

What is PRI?

Answer 6

Primary Rate Interface;

One of the two delivery methods for ISDN, connects PSTN to large PBX systems over T1/E1.

Question 7

What are the two delivery methods for ISDN?

Answer 7

PRI and BRI.

PRI is better, used for large networks to support existing PSTN/PBX/radio/broadcasting services.

Question 8

What is time-division multiplexing?

Answer 8

WAN technology for T1/E1, bandwidth rationed in time slots.

Question 9

T3/E3 WAN uses what connections?

Answer 9

Coaxial cable with BNC

Question 10

T1/T3/E1/E3 are all examples of what?

Answer 10

Circuit-switched connections.

Question 11

Is SONET circuit or packet?

Answer 11

packet-switched

Question 12

OC-3

Answer 12

155 Mbps

Question 13

OC-12

Answer 13

622 Mbps

Question 14

OC-48

Answer 14

2.5 Gbps

Question 15

OC-192

Answer 15

9.95 Gbps

Question 16

What is Metropolitan Ethernet typically delivered over?

Answer 16

MPLS or DWDM

Question 17

What is broadband, what is it used in?

Answer 17

Transmission across multiple frequencies simultaneously.

Used for DOCSIS/cable internet.

Question 18

What is the speed of dialup?

Answer 18

56kbps

Question 19

What frequency is satelite?

Answer 19

2GHz

Question 20

What is WDM

Answer 20

Wavelength division multiplexing

Used for SONET/OC/fiber.

Question 21

What is ATM?

Answer 21

Asynchronous Transfer Mode, protocol transported over SONET

Question 22

What PDU and speed does ATM use?

Answer 22

Fixed 53-byte cells, max speed of OC-192 (almost 10Gbps).

Became less common as IP technology became popular.

Question 23

What is MPLS?

Answer 23

Multi-Protocol Label Switching;
WAN technology that uses the labelling and encapsulation for easy routing decisions, supports any protocol, replacing Frame Relay and ATM.

Question 24

What is PPP?

Answer 24

Point to Point Protocol;

Creates/tunnels a network link between two devices over a WAN, allows authenticaiton and multilink connections.

Question 25

What is PPPoE?

Answer 25

PPP encapsulated in Ethernet. Does not require routing.

Question 26

Where is PPPoE commonly seen?

Answer 26

DSL networks.

Question 27

What is DMVPN?

Answer 27

Dynamic multipoint VPN;

Technology that creates and tears down VPN tunnels across WANs dynamically as needed.

Question 28

What is SIP trunking?

Answer 28

Communication using VoIP to an IP-PBX provider, much more efficient and cheaper than ISDN.

Question 29

What is a demarc?

Answer 29

Demarcation points;
The point where WAN provider conencts to the premises. Usually in a central location or box outside the building, connects to customer premises equipment.

Question 30

What is CSU/DSU?

Answer 30

Channel Service/Data Service Unit;

Simple cable handoff that connects the ISP to customer premise equipment, kinda like a modem.

Question 31

What are 3 authentication methods for PPP?

Answer 31

Password Authentication Protocol (PAP)
Challenge-Handshake Authentication Protocol (CHAP)
Microsoft Challenge-Handshake Authentication Protocol (MS-CHAP)

Question 32

CSU/DSUs sometimes have what?

Answer 32

Monitor jacks, useful for diagnostic equipment.

Question 33

What is a smartjack?

Answer 33

Network interface unit that determines the demarcation point, more intelligent than a CSU/DSU.
WAN provider can do diagnostics on customer network through it without having to visit the locaiton.