Cisco 200-120 Online Practice Questions and Exam Preparation

Cisco 200-120 Online Questions & Answers

• Question 11:

  Why do large OSPF networks use a hierarchical design? (Choose three.)

  A. to decrease latency by increasing bandwidth
  B. to reduce routing overhead
  C. to speed up convergence
  D. to confine network instability to single areas of the network
  E. to reduce the complexity of router configuration
  F. to lower costs by replacing routers with distribution layer switches
  B. to reduce routing overhead
  C. to speed up convergence
  D. to confine network instability to single areas of the network

  ---

  OSPF implements a two-tier hierarchical routing model that uses a core or backbone tier known as area zero (0). Attached to that backbone via area border routers (ABRs) are a number of secondary tier areas. The hierarchical approach is used to achieve the following: ?Rapid convergence because of link and/or switch failures ?Deterministic traffic recovery ?Scalable and manageable routing hierarchy, reduced routing overhead.

• Question 12:

  Host 1 is trying to communicate with Host 2. The e0 interface on Router C is down.

  

  Which of the following are true? (Choose two.)

  A. Router C will use ICMP to inform Host 1 that Host 2 cannot be reached.
  B. Router C will use ICMP to inform Router B that Host 2 cannot be reached.
  C. Router C will use ICMP to inform Host 1, Router A, and Router B that Host 2 cannot be reached.
  D. Router C will send a Destination Unreachable message type.
  E. Router C will send a Router Selection message type.
  F. Router C will send a Source Quench message type.
  A. Router C will use ICMP to inform Host 1 that Host 2 cannot be reached.
  D. Router C will send a Destination Unreachable message type.

  ---

  Host 1 is trying to communicate with Host 2. The e0 interface on Router C is down. Router C will send ICMP packets to inform Host 1 that Host 2 cannot be reached.

• Question 13:

  Refer to the exhibit.

  

  What is the most efficient summarization that R1 can use to advertise its networks to R2?

  A. 172.1.0.0/22
  B. 172.1.0.0/21
  C. 172.1.4.0/22
  D. 172.1.4.0/24 172.1.5.0/24 172.1.6.0/24 172.1.7.0/24
  E. 172.1.4.0/25 172.1.4.128/25 172.1.5.0/24 172.1.6.0/24 172.1.7.0/24
  C. 172.1.4.0/22

  ---

  The 172.1.4.0/22 subnet encompasses all routes from the IP range 172.1.4.0 ?172.1.7.255.

• Question 14:

  Refer to the exhibit.

  

  What is the effect of the configuration that is shown?

  A. It configures SSH globally for all logins.
  B. It tells the router or switch to try to establish an SSh connection first and if that fails to use Telnet.
  C. It configures the virtual terminal lines with the password 030752180500.
  D. It configures a Cisco network device to use the SSH protocol on incoming communications via the virtual terminal ports.
  E. It allows seven failed login attempts before the VTY lines are temporarily shutdown.
  D. It configures a Cisco network device to use the SSH protocol on incoming communications via the virtual terminal ports.

  ---

  Secure Shell (SSH) is a protocol which provides a secure remote access connection to network devices. Communication between the client and server is encrypted in both SSH version 1 and SSH version 2. If you want to prevent non-SSH connections, add the "transport input ssh" command under the lines to limit the router to SSH connections only. Straight (non-SSH) Telnets are refused.

  Reference: www.cisco.com/warp/public/707/ssh.shtml

• Question 15:

  Which IPv6 address is the all-router multicast group?

  A. FF02::1
  B. FF02::2
  C. FF02::3
  D. FF02::4
  B. FF02::2

  ---

  

• Question 16:

  Refer to the exhibit.

  

  A network administrator is configuring an EtherChannel between SW1 and SW2. The SW1 configuration is shown. What is the correct configuration for SW2?

  A. interface FastEthernet 0/1 channel-group 1 mode active switchport trunk encapsulation dot1q switchport mode trunk interface FastEthernet 0/2 channel-group 1 mode active switchport trunk encapsulation dot1q switchport mode trunk
  B. interface FastEthernet 0/1 channel-group 2 mode auto switchport trunk encapsulation dot1q switchport mode trunk interface FastEthernet 0/2 channel-group 2 mode auto switchport trunk encapsulation dot1q switchport mode trunk
  C. interface FastEthernet 0/1 channel-group 1 mode desirable switchport trunk encapsulation dot1q switchport mode trunk interface FastEthernet 0/2 channel-group 1 mode desirable switchport trunk encapsulation dot1q switchport mode trunk
  D. interface FastEthernet 0/1 channel-group 1 mode passive switchport trunk encapsulation dot1q switchport mode trunk interface FastEthernet 0/2 channel-group 1 mode passive switchport trunk encapsulation dot1q switchport mode trunk
  C. interface FastEthernet 0/1 channel-group 1 mode desirable switchport trunk encapsulation dot1q switchport mode trunk interface FastEthernet 0/2 channel-group 1 mode desirable switchport trunk encapsulation dot1q switchport mode trunk

  ---

  If the etherchannel was configured with mode "auto", it was using PagP, so, we need to configure the other switch with "desirable" mode.

  PagP modes: auto | Desirable LACP modes: active | pasive

• Question 17:

  In a GLBP network, who is responsible for the ARP request?

  A. AVF
  B. AVG
  C. Active Router
  D. Standby Router
  B. AVG

  ---

  Members of a GLBP group elect one gateway to be the active virtual gateway (AVG) for that group. Other group members provide backup for the AVG in the event that the AVG becomes unavailable. The AVG assigns a virtual MAC address

  to each member of the GLBP group. Each gateway assumes responsibility for forwarding packets sent to the virtual MAC address assigned to it by the AVG. These gateways are known as active virtual forwarders (AVFs) for their virtual MAC

  address.

  The AVG is responsible for answering Address Resolution Protocol (ARP) requests for the virtual IP address. Load sharing is achieved by the AVG replying to the ARP requests with different virtual MAC addresses.

  Reference: http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ft_glbp.html

• Question 18:

  Which subnet mask would be appropriate for a network address range to be subnetted for up to eight LANs, with each LAN containing 5 to 26 hosts?

  A. 0.0.0.240
  B. 255.255.255.252
  C. 255.255.255.0
  D. 255.255.255.224
  E. 255.255.255.240
  D. 255.255.255.224

  ---

  For a class C network, a mask of 255.255.255.224 will allow for up to 8 networks with 32 IP addresses each (30 usable).

• Question 19:

  Which three statements about RSTP are true? (Choose three.)

  A. RSTP significantly reduces topology reconverging time after a link failure.
  B. RSTP expands the STP port roles by adding the alternate and backup roles.
  C. RSTP port states are blocking, discarding, learning, or forwarding.
  D. RSTP provides a faster transition to the forwarding state on point-to-point links than STP does.
  E. RSTP also uses the STP proposal-agreement sequence.
  F. RSTP uses the same timer-based process as STP on point-to-point links.
  A. RSTP significantly reduces topology reconverging time after a link failure.
  B. RSTP expands the STP port roles by adding the alternate and backup roles.
  D. RSTP provides a faster transition to the forwarding state on point-to-point links than STP does.

  ---

  One big disadvantage of STP is the low convergence which is very important in switched network. To overcome this problem, in 2001, the IEEE with document 802.1w introduced an evolution of the Spanning Tree Protocol: Rapid Spanning

  Tree Protocol (RSTP), which significantly reduces the convergence time after a topology change occurs in the network. While STP can take 30 to 50 seconds to transit from a blocking state to a forwarding state, RSTP is typically able to

  respond less than 10 seconds of a physical link failure.

  RSTP works by adding an alternative port and a backup port compared to STP. These ports are allowed to immediately enter the forwarding state rather than passively wait for the network to converge.

  RSTP bridge port roles:

  *

  Root port ?A forwarding port that is the closest to the root bridge in terms of path cost

  *

  Designated port ?A forwarding port for every LAN segment

  *

  Alternate port ?A best alternate path to the root bridge. This path is different than using the root port. The alternative port moves to the forwarding state if there is a failure on the designated port for the segment.

  *

  Backup port ?A backup/redundant path to a segment where another bridge port already connects. The backup port applies only when a single switch has two links to the same segment (collision domain). To have two links to the same collision domain, the switch must be attached to a hub.

  *

  Disabled port ?Not strictly part of STP, a network administrator can manually disable a port.

• Question 20:

  Refer to the exhibit.

  

  Which address range efficiently summarizes the routing table of the addresses for router Main?

  A. 172.16.0.0./21
  B. 172.16.0.0./20
  C. 172.16.0.0./16
  D. 172.16.0.0/18
  B. 172.16.0.0./20

  ---

  The 172.16.0.0./20 network is the best option as it includes all networks from 172.16.0.0 ?172.16.16.0 and does it more efficiently than the /16 and /18 subnets. The /21 subnet will not include all the other subnets in this one single summarized address.