CCNA 4 Module 4 V3.1 Answers
1. Which of the following correctly describes ISDN BRI? (Choose three.)
two 64 kbps B channels and one 16 kbps D channel
B channel is suitable for voice data
uses in-band signaling
uses out-of-band signaling
offers the equivalent of a T1/E1 connection
twenty-three 64 kbps B channels and one 16 kbps D channel
2. Which of the following is considered out-of-band signaling?
using a frequency outside of the rated bandwidth for transmission
transmitting data over a control channel
using a separate channel for control signals
transmitting control signals over a data channel
3. A network administrator is troubleshooting ISDN connectivity. The administrator suspects the problem lies with the authentication protocol. What command should the administrator use to view the authentication process between the router and the ISDN switch?
debug pap authentication
debug chap authentication
debug ppp authentication
debug isdn authentication
4. Which router command would be used to enter the mode for configuring a T1 PRI connection?
Router(config)# controller t1 {slot/port}
Router(config)# interface pri t1 {slot/port}
Router(config)# interface pri {slot/port} t1
Router(config)# controller {slot/port} t1
5.
The network administrator of XYZ company needs to configure a new ISDN router. After entering the commands shown in the graphic, the administrator tries to access the Internet but the ISDN connection does not open. If the service provider verifies that the problem is with XYZ's configuration, what is a possible cause of the problem?
The dialer map is configured incorrectly.
The encapsulation type is configured incorrectly.
The dialer group is configured incorrectly.
The ACL is configured incorrectly.
The isdn switch-type command needs to be configured globally.
6. Which of the following protocols can be used to encapsulate data traffic sent from a router BRI interface? (Choose two.)
Link Access Protocol - Data
High-Level Data Link Control
Logical Link Control
Serial Data Link Control
Point to Point protocol
Binary Synchronous Control protocol
7.
A small company uses an ISDN WAN link to transfer e-mail to remote sites. What command would the administrator use to determine if the ISDN link is up?
show isdn status
show isdn active
show dialer
show interface bri0/0
debug isdn active
8. Which command configures an ISDN interface to use a switch type which is different from that used on other interfaces on the router?
Router(config)#switch-type switch-type
Router(config-if)#switch-type switch-type
Router(config)#isdn switch-type switch-type
Router(config-if)#isdn switch-type switch-type
9. Which of the following is essential for all ISDN BRI interface configurations?
ISDN switch type
line encoding technique
line framing method
local directory number
service profile identifier
10. You have just taken delivery of a new US standard Cisco 2620 router that includes a BRI "U" interface? Which of the following describes how this router will be connected in the ISDN network?
An external terminal adapter (TA) must be attached to the router for connectivity.
An NT1 must be connected to the router for connectivity.
The router is a TE1 device and is ready to connect to the provider's network.
The router is a TE2 device and requires both a TA and NT1 for connectivity.
11. What must be configured for an ISDN PRI connection? (Choose three.)
ISDN switch type
Service Profile Identifier (SPID)
Dial-on-Demand Routing (DDR)
PRI group time slot
T1/E1 controller, framing type and line coding
12.
A network administrator is troubleshooting an ISDN connectivity problem. Users are complaining they cannot connect to the Internet. The network administrator suspects the ISDN connection attempt is timing out before a connection can be established. What command would the network administrator use to determine what the "wait for carrier" timeout value is set to?
show isdn status
show isdn active
show dialer
show interfaces bri0/0
debug isdn q931
show ISDN interfaces
13. What is a reason why static routes are preferred over dynamic routes for DDR to operate on an ISDN interface?
An ISDN interface will not allow dynamic routing updates that use broadcast technology.
A dynamic route will take precedence over a static route because of its lower administrative distance.
Dynamic routing can never be considered interesting traffic by default.
Dialer-list configuration does not support dynamic routing.
Dynamic routes may cause the ISDN connection to dial constantly to transmit updates.
14. Which of the following describes the use of a SPID? (Choose two.)
selects the ISDN switch type
identifies the line configuration of the BRI service
allows multiple ISDN devices to share the local loop
designates whether a device is a TE1 or TE2
allows ISDN broadcasts
15. Which command is used within an existing ISDN network to display current call information, including the called number?
show isdn status
show isdn active
show interfaces bri0/0
show ip interfaces
16. Which of the following are true of ISDN routers configured with dialer profiles? (Choose two.)
They do not use ACL to define interesting traffic.
Their B channels can be configured with different subnets and encapsulation types.
Their BRI interfaces can belong to multiple dialer pools.
They use PPP only.
They can only use the CHAP authentication protocol.
17. A network administrator in Europe has been asked to provide the network with an ISDN WAN link. The router available to provide the WAN connection is a non-modular Cisco router with an S/T interface. What further equipment will be provided by the ISDN service provider for the ISDN connection?
Nothing. The router is already suitable.
BRI WAN interface card to install in the router
an external NT1 to terminate the local loop
a TA/NT1 device to install on the router
18. Why must routers be configured to specify the ISDN switch type?
Switches use various implementations of Q.931.
The IOS of most routers lacks the ability to autosense the switch.
The switch must know what type of router it is communicating with.
The Layer 3 connection between the terminal equipment and the ISDN switch is not standardized.
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