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At which two layers of the OSI model does a WAN operate?
- Physical Layer
- Data Link Layer
Which WAN technology uses a fixed payload of 48 bytes and is transported across both switched and permanent virtual circuit.
What are two advantages of an analog PSTN WAN connection?
What three terms are associated with ISDN?
- time-division multiplexing
- data bearer channels
What can cause a reduction in available bandwidth on a cable broadband connection?
increased number of subscribers
Which two devices are commonly used as data communications equipment?
Which statement is TRUE about data connectivity between a customer and a service provider?
Demarcation Point is the place where the responsibility for the connection changes from the user to the service provider.
Which statement about WAN protocols is correct?
Most WAN protocols use HDLC or a variant of HDLC as a framing mechanism.
What is an advantage of packet-switched technology over circuit-switched technology?
Packet-switched networks can efficiently use multiply routes inside a service provider network.
For digital lines, which device is used to establish the communications link between the customer equipment and the local loop?
Which of the following is FALSE regarding packet-switching?
Uses Time-division multiplexing (TDM) gives each conversation a share of the connection in turn.
What type of connectivity is established when VPNs are used from the remote site to the private network?
Refer to the figure. On the basis of the show interface Serial 0/0 output, how many NCP sessions have been established?
Refer to the figure. Which statement is true about PPP operation?
Both the link establishment and network-layer phase completed successfully.
Refer to the figure. What statement is true regarding the output shown?
Layer 3 data is able to flow across this link.
Refer to the figure. Router R1, the DCE device, has just been configured for PPP encapsulation with authentication. What series of commands will allow another router, the DTE device, to communicate over its serial s0/0/0 interface to router R1?
- Router(config)# hostname R3
- R3(config)# username R1 password Cisco
- R3(config)# interface Serial 0/0/0
- R3(config-if)# encapsulation ppp
- R3(config-if)# ip address 172,16.2.2 255.255.255.0
- R3(config-if)# ppp authentication chap
Refer to the figure. What can be concluded about the function of the Serial 0/0/0 interface on the router after the commands are entered?
The serial link will be closed if the number of received packets at the destination node falls below 90 percent of the packets that are sent.
Which two statements are correct about HDLC encapsulation?
- HDLC implementation in Cisco routers is proprietary.
- HDLC is the default serial interface encapsulation on Cisco routers.
Which two options can LCP negotiate?
- link quality
Which PPP configuration option can be used to establish load balancing over the interfaces of a router?
What function do Network Control Protocols provide for a PPP connection?
to allow multiple Layer 3 protocols to operate over the same physical link
Which three statements correctly describe PPP authentication?
- PPP sends passwords in clear text.
- CHAP uses repeated challenges for verification.
- CHAP uses a challenge/ response that is based on MD5 hash algorithm.
Which two statements are true about time-division multiplexing (TDM)?
- Original data streams must be reconstructed at the destination.
- Multiple channels can transmit over a single link.
Which three statements are true regarding LCP?
- It terminates the link upon user request or the expiration of an inactivity timer.
- It is responsible for negotiating link establishment.
- It can test the link to determine if link quality is sufficient to bring up the link.
What best describes the benefits of using Frame Relay as opposed to a leased line?
Lower equipment cost and subscription cost especially is the network traffic are bursty.
What best describes the use of a data-link connection identifier (DLCI)?
locally significant address used to identify a virtual circuit
Which two items allow the router to map data link layer addresses to network layer addresses in a Frame Relay network?
- LMI status messages
- Inverse ARP
Refer to the figure. A ping is sent to address 192.168.50.10 from the Peanut router. Which DLCI will be used to send the ping?
Refer to the figure. What effect does the point-to-point configuration on subinterface S0/0.110 have on the operation of the router?
It eliminates split horizon issues without increasing the likelihood of routing loops.
Which three actions might a Frame Relay switch perform when it detects an excessive build-up of frames in its queue?
- drops frames from the queue that have the DE bit set
- sets the FECN bit on all frames it receives on the congested link
- sets the BECN bit on all frames it places on the congested link
Refer to the exhibit. What can be determined about the Frame Relay switch from the output shown?
It is experiencing congestion.
Refer to the exhibit. Frame Relay connectivity has been configured in the network and OSPF is used as the routing protocol. Router R1 can successfully ping R2 serial interface. When R1 attempts to ping network 192.168.3.0/24 the ping fails. What additional configuration should be applied on all routers to remedy the problem?
Add the broadcast keyword in the Frame Relay map command on both router.
Refer to the figure. You are a network administrator who has been tasked with completing Frame Relay topology that interconnects two remote sited. Router HQ belongs to both the 172.16.1.0/24 and 172.16.2.0/24 subnets with IP addresses of 172.16.1.3 and 172.16.2.3 respectively. Traffic between R1 and R2 must travel through HQ first. How should the serial interface on HQ be configured to complete the topology?
two point-to-point subinterfaces
Refer to the exhibit. Which statement explains why the Frame Relay connection between R1 and R2 is failing?
The frame-relay map commands are using incorrect DLCIs.
Refer to the exhibit. Router R1 has been configured for Frame Relay connectivity to routers R2 and R3. Which set of configuration options for routers R2 and R3 would provide each router connectivity to R1?
- R2(config)# interface serial0/0/1.201 point-to-point
- R2(config-if)# frame-relay interface-dlci 201
- R3(config)# interface serial0/0/1.301 point-to-point
- R3(config-if)# frame-relay interface-dlci 301
Refer to the exhibit. What can be determined from the output?
Serial 0/0/0 has the feature frame-relay inverse-arp enabled.
Refer to the figure. Router R1 has been configured for Frame Relay connectivity to routers R2 and R3. What configuration option should be configured on the R2 and R3 serial interfaces in order for ALL routers (R1, R2 and R3) to ping each other successfully?
- R2(config-if)# frame-relay map ip 10.1.1.1 201 broadcast
- R2(config-if)# frame-relay map ip 10.1.1.3 201 broadcast
- R3(config-if)# frame-relay map ip 10.1.1.1 301 broadcast
- R3(config-if)# frame-relay map ip 10.1.1.2 301 broadcast
Refer to the figure. Which two outcomes occur from the configuration shown?
- Frames sent to 10.1.1.1 by RT_1 will have a data link layer address of 22.
- The router will use DLCI 22 to forward data to 10.1.1.1.
Which two statements are TRUE regarding network security?
- Protecting network devices from physical damage caused by water or electricity is a necessary part of the security policy.
- Both experienced hackers who are capable of writing their own exploit code and inexperienced individuals who download exploits from the Internet pose a serious threat to network security.
Which two statements are true about network attacks?
- Attackers install “Backdoors” to provide them with a way to enter the system without being detected.
- A brute-force attack searches to try every possible password from a combination of characters.
Users are unable to access a company server. The system logs show that the server is operating slowly because it is receiving a high level of fake requests for service. Which type of attack is occurring?
Which two statements regarding preventing network attacks are true?
- Physical security threat mitigation consists of controlling access to device console ports, labeling critical cable runs, installing UPS systems, and providing climate control.
- Changing default usernames and passwords and disabling or uninstalling unnecessary services are aspects of device hardening.
The Cisco IOS image naming convention allows identification of different versions and capabilities of the IOS. What information can be gained from the filename c2600-d-mz.121-4?
- The IOS is for the Cisco 2600 series hardware platform.
- The software is version 12.1.4th revision.
Which two conditions should the network administrator verify before attempting to upgrade a Cisco IOS image using a TFTP server?
- Verify connectivity between the router and TFTP server using the ping command.
- Verify that there is enough flash memory for the new Cisco IOS image using the show flash command.
The password recovery process begins in which operating mode and using what type of connection?
- ROM monitor (ROMmon)
- direct connection through the console port
What is the best defense for protecting a network from phishing exploits?
Schedule training for all users
Refer to the exhibits. What is the purpose of the “ip ospf message-digest-key 1 md5 cisco” statement in the configuration?
to specify a key that is used to authenticate routing updates
Which of the following must be configured first before configuring SSH on VTY lines?
What is the configuration register setting that will cause the router to bypass the startup configuration?
Describe an Open Network.
- Easy to configure and administer
- Easy for end users to access network resources
- Security cost: least expensive
- Least secure
Describe a Closed Network.
- Most difficult to configure and administer
- Most difficult for end users to access resources
- Security cost: most expensive
- Most secure
Describe a Restrictive Network.
- More difficult to configure and administer
- More difficult for end users to access resources
- Security cost: more expensive
- More secure than Open Network, least secure than Closed Network.
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