WAN Connections

Question 1

Dedicated Lease Line

Answer 1

Logical connection between service provider to another remote site

Question 2

Circuit-Switched

Answer 2

-Similar to phone call, only brought open when needed.
-ISDN

Question 3

Packet-switched

Answer 3

-Works like dedicated lease line, but all customers use same bandwidth
-Given SLA
-Virtual circuits

Question 4

Metro Ethernet

Answer 4

Metropolitan area Ethernet
-Simply providing Ethernet on both sides instead of changing media.
-could be Ethernet w/MPLS in middle, Ethernet over dwdm, Ethernet over sdh, or pure Ethernet.
-less expensive and more common that specialized serial ports used in a csu/dsu

Question 5

Frame Relay

Answer 5

Virtual circuits
Point to point or point to multipoint
Layer 2
Sharing bandwidth
Replaced by mpls
Packet switched wan technology

Question 6

ATM

Answer 6

-Asynchronous Transfer Mode
-Layer 2
-Permanent virtual circuits and switched virtual circuits
-Fixed 53-byte cells(48-byte payload with 5-byte header)
-UNI (user-network interface)
—atm switches to endpoints
-NNI (network-node interface)
—atm switch to atm switch

Question 7

MPLS

Answer 7

-Multiprotocol Label Switching
-routing technique that directs data from one node to the next based on short path labels rather than long network addresses
-avoids complex lookups in a routing table
-Common network
-Supports frame relay and atm on same backbone
-packets have label(pushing and popping)

Question 8

PPP

Answer 8

-Point to Point protocol
-Way to connect 2 devices to send other protocols over that wan link (layer 2 protocol commonly used to transmit multiple layer 3 protocols)
-layer 2
-authentication, error detection, multi link, compressed
-PAP, CHAP, MS-CHAP
-each layer 3 control protocol runs an instance of PPP’s Link Control Protocol(LCP)

Question 9

PPPoE

Answer 9

Encapsulates PPP frames within Ethernet frames
-common with DSL
-allows for authentication over Ethernet

Question 10

DMVPN

Answer 10

-Dynamic Multipoint VPN
-common with Cisco
-tunnels dynamically built on demand
-more efficient than a remote site having to communicate back to main office before reaching the other remote site.

Question 11

POTS

Answer 11

Plain Old Telephone Service
-analog connections using PSTN (public switched telephone network)

Question 12

ISDN

Answer 12

-Integrated Services Digital Network
-circuit-switched wan technology
-changes internal connections of PSTN carrying analog signals to time-division multiplexed digital signals
-older tech to carry data over B channels
-BRI (basic rate interface) or PRI (primary rate interface)

Question 13

SONET

Answer 13

-Synchronous Optical Network
-layer 1 tech using fiber as media
-transports layer 2 encapsulation like atm
-can be bus or ring

Question 14

Cable Modems

Answer 14

HFC(Hybrid Fiber-Coax)
DOCSIS (Data over cable Service interface Specification)
—determines frequency ranges used for upstream and downstream data transmission

Question 15

Satellite Modems

Answer 15

1/2 delay times
Relatively fast like DSL modem, but low bandwidth

Question 16

mGRE

Answer 16

-Multipoint generic routing encapsulation
-protocol that can be used to enable one node to communicate with many by encapsulating layer 3 protocols to create tunnels over another network.
-point to multipoint link
-combined with DMVPN for security

-think of ferry having to encapsulate cars over water
-tunneling protocol/does not provide encryption

Question 17

T1 data rate

Answer 17

1.544 Mbps

Question 18

T3 data rate

Answer 18

44.736 Mbps

Question 19

E1 data rate

Answer 19

2.048 Mbps

Question 20

E3 data rate

Answer 20

34.4 Mbps

Question 21

SDWAN

Answer 21

-software defined wan
-network that is abstracted from its hardware which creates a virtualized network overlay

Question 22

CSU/DSU

Answer 22

-Channel Service Unit/Data Service Unit
-hardware device that converts digital data frames from communications technology used on a lan into frames appropriate to a wan and vice versa.
-about the size of external modem
-will have this with digital lines like t1,t3,e1,e3

Question 23

PAP (PPP Auth)

Answer 23

One way authentication between client and server
-sent in clear text

Question 24

CHAP (PPP auth)

Answer 24

Challenge-Handshake Authentication Protocol
-one way authentication using 3 way handshake
-credentials hashed before transmission

Question 25

MS-CHAP (PPP auth)

Answer 25

Microsoft Challenge-Handshake Authentication Protocol
-Microsoft’s enhanced version of CHAP
-includes 2-way authentication

Question 26

DSL

Answer 26

Digital Subscriber Line
ADSL
-asymmetric
-max dist to dslam: 18,000 ft
-voice and data same line

SDSL
-symmetric
-dslam dist: 12,000 ft
-no simultaneous voice and data

VDSL
-very high bit rate
-dist: 4,000 ft