CCNA Portable Command Guide (2nd Edition)
81 Which service takes information from multiple sources and allocates bandwidth on a single media?
81 Which service takes information from multiple sources and allocates bandwidth on a single media?
A. Time-division Multiplexing (TDM)
B. Signaling System 7 (SS7)
C. X.25
D. Frame relay
Ans A
82 Which three devices can be used to convert the user data from the DTE into a form acceptable to the WAN service's facility?
A. Modem
B. CSU/DSU
C. TA/NT1
D. CO
E. SS7
Ans A, B & C
A modem, CSU/DSU (Channel Service Unit/Data Service Unit), or TA/NT1 (Terminal Adapter/Network Termination 1) can be used to convert the user data from the DTE into a form acceptable to the WAN service's facility.
83 What is the juncture at which the CPE ends and the local loop portion of the service begins?
A. Demarc
B. CO
C. Local loop
D. Last-mile
Ans A
The demarcation or demarc is the juncture at which the CPE ends and the local loop portion of the service begins. The CO (Central Office) is the nearest point of presence for the provider's WAN service. The local loop or "last-mile" is the cabling that extends from the demarc into the WAN service provider's central office.
84 You can access three forms of WAN services with Cisco routers. Select the three forms:
A. Switched or relayed services
B. Interface front end to IBM enterprise data center computers
C. Using protocols that connect peer-to-peer devices like HDLC or PPP encapsulation.
D. IPX/SPX
E. NetBEUI
Ans: A, B & C
You can access three forms of WAN services with Cisco routers. Switched or relayed services include X.25, Frame Relay, and ISDN. An interface front end to IBM enterprise data center computers includes SDLC. And, you can access the services of WAN providers using protocols that connect peer devices such as HDLC and PPP encapsulation. IPX/SPX and NetBEUI are LAN protocols.
85 Select the fields for the Cisco HDLC protocol:
A. Flag, Address, Control
B. Flag, Address, Control, Protocol, LCP (Code, Identifier, Length, Data), FCS, Flag
C. Flag, Address, Control, Data, FCS, Flag
D. Flag, Address, Control, Proprietary, Data, FCS, Flag
Ans D
The Cisco HDLC frame format is Flag, Address, Control Proprietary, Data, FCS, Flag. The PPP frame format is Flag, Address, Control, Protocol, LCP (Code, Identifier, Length, Data), FCS, Flag. The SDLC and LAPB format is Flag, Address, Control, Data, FCS, Flag.
85: Select the physical interfaces that PPP can be configured on a Cisco router:
A. Asynchronous serial
B. HSSI
C. ISDN
D. Synchronous serial
Ans A, B, C & D
All four of them can carry PPP traffic. HSSI is High Speed Serial Interface.
86 Select the correct statements about PPP and SLIP for WAN communications?
A. PPP uses its Network Control Programs (NCPs) component to encapsulate multiple protocols.
B. PPP can only transport TCP/IP
C. SLIP can only transport TCP/IP.
D. SLIP uses its Network Control Programs (NCPs) component to encapsulate multiple protocols.
Ans A & C
87a Which protocol for PPP LCP (Link Control Protocol) performs a challenge handshake?
A. CHAP
B. PAP
C. UDP
D. IPX
Ans: A
87b Which form of PPP error detection on Cisco routers monitors data dropped on a link?
A. Quality
B. Magic Number
C. Error Monitor
D. Droplink
Ans: A
The Quality protocol monitors data dropped on a link. Magic Number avoids frame looping.
88 Which protocol for PPP provides load balancing across multiple links?
A. Multilink Protocol (MP)
B. Quality
C. Magic Number
D. Stacker
E. Predictor
Ans A
89 As the system administrator, you type "ppp authentication chap pap secret". Which authentication method is used first in setting up a session?
A. secret
B. PAP
C. CHAP
D. PPP/SLIP
Ans C
90 Select the compression protocols for PPP?
A. Stac
B. Predictor
C. Quality
Ans: A & B
91 What are the three phases of PPP session establishment?
A. Link establishment phase
B. Authentication phase
C. Network layer protocol phase
D. Handshake phase
E. Dial-in phase
Ans A, B & C
92 What is the default IPX Ethernet encapsulation?
A.) SNAP
B.) Arpa
C.) 802.2
D.) Novell-Ether
E.) SAP
Ans D
93 What must be true for two Routers running IGRP to communicate their routes?
A.) Same autonomous system number
B.) Connected using Ethernet only
C.) Use composite metric
D)Configured for PPP
Ans A
94 The following is partial output from a routing table, identify the 2 numbers in the square brackets; '192.168.10.0 [100/1300] via 10.1.0.1, 00:00:23, Ethernet1'
A.) 100 = metric, 1300 = administrative distance
B.) 100 = administrative distance, 1300 = hop count
C.) 100 = administrative distance, 1300 = metric
D.) 100 = hop count, 1300 = metric
Ans C
95 Identify 3 methods used to prevent routing loops?
A.) Split horizon
B.) Holddown timers
C.) Poison reverse
D.) SPF algorithm
E.) LSP's
Ans A B C
96 Which statement is true regarding full duplex?
A.) Allows for transmission and receiving of data simultaneously
B.) Only works in a multipoint configuration
C.) Does not affect the bandwidth
D.) Allows for transmission and receiving of data but not a the same time
Ans A
Full duplex is just the opposite of half duplex. It handles traffic in both directions simultaneously.
97 Identify the switching method that receives the entire frame then dispatches it?
A.) Cut-through
B.) Receive and forward
C.) Store and forward
D.) Fast forward
Ans C
Store and forward switching receives the entire frame before dispatching it.
98Identify the purpose of ICMP?
A.) Avoiding routing loops
B.) Send error and control messages
C.) Transporting routing updates
D.) Collision detection
Ans B
ICMP is used to send error and control messages. Ping uses ICMP to carry the echo-request and echo-reply.
99Which statement is true regarding the user exec and privileged exec mode?
A.) The '?' only works in Privileged exec
B.) They are identical
C.) They both require the enable password
D.) User exec is a subset of the privileged exec
Ans D
The user exec mode is a subset of the privileged exec mode. Only a certain number of commands are available at the user exec mode.
100 Which OSI layer end to end communication, segmentation and re-assembly?
A.) Network
B.) Transport
C.) Physical
D.) Application
E.) Data-Link
F.) Presentation
Ans B
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