Cisco 300-410 Online Practice Questions and Exam Preparation

Cisco 300-410 Online Questions & Answers

• Question 421:

  Which of the following statements are true regarding two OSPF routers to become neighbors? (Choose two.)

  A. Must use the same ASN
  B. Must have identical hello and dead timers
  C. Must have matching MTU's on the physical network links that connect the routers.
  D. Need not be on the same subnet.
  B. Must have identical hello and dead timers
  C. Must have matching MTU's on the physical network links that connect the routers.

• Question 422:

  Refer to the exhibit.

  

  An OSPF neighbor relationship between R2 and R3 is showing stuck in EXCHANGE/EXSTART state. The neighbor is established between R1 and R2. The network engineer can ping from R2 to R3 and vice versa, but the neighbor is still down. Which action resolves the issue?

  A. Restore the Layer 2/Layer 3 conectivity issue in the ISP network.
  B. Match MTU on both router interfaces or ignore MTU.
  C. Administrative "shut then no shut" both router interfaces.
  D. Enable OSPF on the interface, which is required.
  B. Match MTU on both router interfaces or ignore MTU.

  ---

  After two OSPF neighboring routers establish bi-directional communication and complete DR/BDR election (on multi-access networks), the routers transition to the exstart state. In this state, the neighboring routers establish a master/slave relationship and determine the initial database descriptor (DBD) sequence number to use while exchanging DBD packets.

  Neighbors Stuck in Exstart/Exchange State

  The problem occurs most frequently when attempting to run OSPF between a Cisco router and another vendor's router. The problem occurs when the maximum transmission unit (MTU) settings for neighboring router interfaces don't match. If the router with the higher MTU sends a packet larger that the MTU set on the neighboring router, the neighboring router ignores thepacket.

• Question 423:

  You instructed your assistant to configure load balancing on a router. The router currently has two routes to network A. One route has a cost of 15, and the other has a cost of 30.

  What command should the assistant execute to instruct the router to treat the two routes as equal without including any other routes in the load balancing?

  A. routerA(config)# variance 2
  B. routerA(config-router)# variance 2
  C. routerA(config)# variance 3
  D. routerA(config-router)# variance 3
  B. routerA(config-router)# variance 2

  ---

  The correct command to instruct the router to treat the two routes as equal is variance 2. It must be entered in EIGRP configuration mode, as evidenced by the routerA(config-router)# prompt. The number that comes after the command is called the multiplier. A multiplier of two tells the router that any route that is within twice the metric of the best route will be considered equal to the best route.

  The default setting for variance is one, which indicates that the routes must be equal to be considered for load balancing. An additional requirement of load balancing is that the alternate route's feasible distance must not be higher than the advertised distance of the route, which could indicate a routing loop.

  The assistant should not execute the variance 2 command at the routerA(config)# prompt, which is global configuration mode. The variance command must be entered in EIGRP configuration mode at the routerA (config-router)# prompt.

  The assistant should not use the variance 3 command in either mode because that would direct the router that any route within three times the cost of the best route (in this scenario, a cost of 45) would be considered equal to the cost of the best route. The scenario requires that two routes be load balanced. Because one route has a cost of 15 and the other has a cost of twice 15 (30), the variance multiplier must be two.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify EIGRP load balancing

  References:

  Cisco > Home > Support > Technology Support > IP > IP Routing > Design > Design Technotes > How Does Unequal Cost Path Load Balancing (Variance) Work in IGRP and EIGRP? Cisco > Support > Technology Support > IP > IP Routing > Design > Design Technotes > Route Selection in Cisco Routers > Document ID: 8651

• Question 424:

  You are configuring Open Shortest Path First (OSPF) protocol for IPv6 on Router5. The router has two interfaces, which have been configured as follows:

  S0/0 - 192.168.5.1/24 S0/1 - 10.0.0.6/8

  You would like OSPF to route for IPv6 only on the S0/0 network and not route for IPv6 on the S0/1 network. The process ID you have chosen to use is 25. You do not want to apply an IPv6 address yet.

  Which of the following command sets would enable OSPF for IPv6 as required?

  A. Router5(config)#ipv6 ospf 25 Router5(config)# network 192.168.5.0
  B. Router5(config)#ipv6 ospf 25 Router5(config)#router-id 192.168.5.1
  C. Router5(config)#ipv6 unicast-routing Router5(config)#ipv6 router ospf 25 Router5(config-rtr)#router-id 1.1.1.1 Router5(config)#interface S0/0 Router5(config-if)#ipv6 ospf 25 area 0
  D. Router5(config)#ipv6 unicast-routing Router5(config)#ipv6 ospf 25 Router5(config-rtr)#router-id 1.1.1.1
  C. Router5(config)#ipv6 unicast-routing Router5(config)#ipv6 router ospf 25 Router5(config-rtr)#router-id 1.1.1.1 Router5(config)#interface S0/0 Router5(config-if)#ipv6 ospf 25 area 0

  ---

  The correct command sequence would be as follows:

  Router5(config)# ipv6 unicast-routing

  Router5(config)# ipv6 router ospf 25

  Router5(config-rtr)# router-id 1.1.1.1

  Router5(config)# interface S0/0

  Router5(config-if)# ipv6 ospf 25 area 0

  The first line enables IPv6 routing with the ipv6 unicast-routing command. The second line enables OSPF routing for IPv6 with the ipv6 router ospf command. The third assigns a necessary router ID (which was chosen at random) with the router-id command. The last two lines enable OSPF for area 0 on the proper interface.

  The following command set is incorrect because it does not enable OSPF routing for IPv6, assign a necessary router ID, or enable OSPF for area 0 on the proper interface:

  Router5(config)# ipv6 ospf 25

  Router5(config)# network 192.168.5.0

  This command set also displays incorrect use of the network command. The network command would be used with OSPF v2.

  The following command set fails to enable OSPF routing for IPv6, assign a necessary router ID, or enable OSPF for area 0 on the proper interface:

  Router5(config)# ipv6 ospf 25

  Router5(config)# router-id 192.168.5.1

  It also assigns the router ID under global configuration mode, rather than under router ospf 25 configuration mode as required.

  The following command set fails to enable OSPF for area 0 on the proper interface:

  Router5(config)# ipv6 unicast-routing

  Router5(config)# ipv6 ospf 25

  Router5(config-rtr)# router-id 1.1.1.1

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify OSPF for IPv6

  References:

  Cisco > Implementing OSPF for IPv6 > How to Implement OSPF for IPv6 Cisco > Cisco IOS IPv6 Command Reference > ipv6 unicast-routing Cisco > Cisco IOS IPv6 Command Reference > ipv6 ospf area

• Question 425:

  Refer to the exhibit.

  

  Which command must be configured to make VRF CCNP work?

  A. interface Loopback0 ip address 10.1.1.1 255.255.255.0 vrf forwarding CCNP
  B. interface Loopback0 ip address 10.1.1.1 255.255.255.0
  C. interface Loopback0 vrf forwarding CCNP
  D. interface Loopback0 ip address 10.1.1.1 255.255.255.0 ip vrf forwarding CCNP
  B. interface Loopback0 ip address 10.1.1.1 255.255.255.0

  ---

  https://community.cisco.com/t5/mpls/interface-ip-removed-after-apply-the-ip-vrf-forwarding/td-p/487122

• Question 426:

  Which transport layer protocol is used to form LDP sessions?

  A. UDP
  B. SCTP
  C. TCP
  D. RDP
  C. TCP

  ---

  LDP multicasts hello messages to a well-known UDP port (646) in order to discover neighbors. Once the discovery is accomplished, a TCP connection (port 646) is established and the LDP session begins. LDP keepalives ensure the health of the session. Thanks to the LDP session, LDP messages create the label mappings required for a FEC. Withdraw messages are used when FECs need to be torn down.

• Question 427:

  DRAG DROP

  Drag and drop the OSPF adjacency states from the left onto the correct descriptions on the right.

  Select and Place:

  

  

  ---

  Explanation/Reference:

  

  Down

  This is the first OSPF neighbor state. It means that no information (hellos) has been received from this neighbor, but hello packets can still be sent to the neighbor in this state. During the fully adjacent neighbor state, if a router doesn't receive hello packet from a neighbor within the Router Dead Interval time (RouterDeadInterval = 4*HelloInterval by default) or if the manually configured neighbor is being removed from the configuration, then the neighbor state changes from Full to Down.

  Attempt

  This state is only valid for manually configured neighbors in an NBMA environment. In Attempt state, the router sends unicast hello packets every poll interval to the neighbor, from which hellos have not been received within the dead interval.

  Init

  This state specifies that the router has received a hello packet from its neighbor, but the receiving router's ID was not included in the hello packet. When a router receives a hello packet from a neighbor, it should list the sender's router ID in its hello packet as an acknowledgment that it received a valid hello packet.

  2-Way

  This state designates that bi-directional communication has been established between two routers. Bi-directional means that each router has seen the other's hello packet. This state is attained when the router receiving the hello packet sees its own Router ID within the received hello packet's neighbor field. At this state, a router decides whether to become adjacent with this neighbor. On broadcast media and non-broadcast multiaccess networks, a router becomes full only with the designated router (DR) and the backup designated router (BDR); it stays in the 2-way state with all other neighbors. On Point-to-point and Point-to-multipoint networks, a router becomes full with all connected routers.

  At the end of this stage, the DR and BDR for broadcast and non-broadcast multiacess networks are elected. For more information on the DR election process, refer to DR Election. Note: Receiving a Database Descriptor (DBD) packet from a neighbor in the init state will also a cause a transition to 2-way state.

  Exstart

  Once the DR and BDR are elected, the actual process of exchanging link state information can start between the routers and their DR and BDR. (ie. Shared or NBMA networks). In this state, the routers and their DR and BDR establish a master-slave relationship and choose the initial sequence number for adjacency formation. The router with the higher router ID becomes the master and starts the exchange, and as such, is the only router that can increment the sequence number. Note that one would logically conclude that the DR/BDR with the highest router ID will become the master during this process of master-slave relation. Remember that the DR/BDR election might be purely by virtue of a higher priority configured on the router instead of highest router ID. Thus, it is possible that a DR plays the role of slave. And also note that master/slave election is on a per-neighbor basis.

  Exchange

  In the exchange state, OSPF routers exchange database descriptor (DBD) packets. Database descriptors contain link-state advertisement (LSA) headers only and describe the contents of the entire link-state database. Each DBD packet has a sequence number which can be incremented only by master which is explicitly acknowledged by slave. Routers also send link-state request packets and link-state update packets (which contain the entire LSA) in this state. The contents of the DBD received are compared to the information contained in the routers link-state database to check if new or more current link-state information is available with the neighbor.

  Loading

  In this state, the actual exchange of link state information occurs. Based on the information provided by the DBDs, routers send link-state request packets. The neighbor then provides the requested link- state information in link-state update packets. During the adjacency, if a router receives an outdated or missing LSA, it requests that LSA by sending a link-state request packet. All link-state update packets are acknowledged.

  Full

  In this state, routers are fully adjacent with each other. All the router and network LSAs are exchanged and the routers' databases are fully synchronized. Full is the normal state for an OSPF router. If a router is stuck in another state, it is an indication that there are problems in forming adjacencies. The only exception to this is the 2-way state, which is normal in a broadcast network. Routers achieve the FULL state with their DR and BDR in NBMA/broadcast media and FULL state with every neighbor in the remaining media such as point-to- point and point-to-multipoint.

  Note: The DR and BDR that achieve FULL state with every router on the segment will display FULL/DROTHER when you enter the show ip ospf neighbor command on either a DR or BDR. This simply means that the neighbor is not a DR or BDR, but since the router on which the command was entered is either a DR or BDR, this shows the neighbor as FULL/DROTHER.

  Reference:

  https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13685-13.html

  + Each router compares the DBD packets that were received from the other router: Exchange

  + Routers exchange information with other routers in the multiaccess network: Exstart

  + The neighboring router requests the other routers to send missing entries: Loading

  + The network has already elected a DR and a backup BDR: 2-way

  + The OSPF router ID of the receiving router was not contained in the hello message: Init

  + No hellos have been received from a neighbor router: Down

  When OSPF adjacency is formed, a router goes through several state changes before it becomes fully adjacent with its neighbor.

  The states are Down -> Attempt (optional) -> Init -> 2-Way -> Exstart -> Exchange -> Loading -> Full. Short descriptions about these states are listed below:

  Down: no information (hellos) has been received from this neighbor. Attempt: only valid for manually configured neighbors in an NBMA environment. In Attempt state, the router sends unicast hello packets every poll interval to the neighbor, from which hellos have not been received within the dead interval.

  Init: specifies that the router has received a hello packet from its neighbor, but the receiving router's ID was not included in the hello packet

  2-Way: indicates bi-directional communication has been established between two routers. Exstart: Once the DR and BDR are elected, the actual process of exchanging link state information can start between the routers and their DR and BDR.

  Exchange: OSPF routers exchange and compare database descriptor (DBD) packets Loading: In this state, the actual exchange of link state information occurs. Outdated or missing entries are also requested to be resent.

  Full: routers are fully adjacent with each other

  http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093f0e.shtml

  https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13685-13.html

  https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13685-13.html

• Question 428:

  Refer to the exhibit. A network administrator is troubleshooting IPv6 address assignment for a DHCP client that is not getting an IPv6 address from the server.

  ipv6 dhcp server:

  ipv6 unicast-routing ! int e0/1 ipv6 enable ipv6 add 2001:11::1/64 ipv6 nd other-config-flag no shut ipv6 dhcp server IPv6Pool ! ipv6 dhcp pool IPv6Pool dns-server 2002:555::1 domain-name my.net

  ipv6 dhcp client:

  interface Ethernet0/1 no ip address ipv6 address dhcp ipv6 enable no shut

  

  Which configuration retrieves the client IPv6 address from the DHCP server?

  A. ipv6 address autoconfig command on the interface
  B. ipv6 dhcp server automatic command on DHCP server
  C. ipv6 dhcp relay-agent command on the interface
  D. service dhcp command on DHCP server
  A. ipv6 address autoconfig command on the interface

• Question 429:

  What is a MPLS PHP label operation?

  A. Downstream node signals to remove the label.
  B. It improves P router performance by not performing multiple label lookup.
  C. It uses implicit-NULL for traffic congestion from source to destination forwarding
  D. PE removes the outer label before sending to the P router.
  A. Downstream node signals to remove the label.

• Question 430:

  Refer to the exhibit.

  

  R3 cannot authenticate via TACACS. Which configuration resolves the issue?

  A. tacacs server SITE6_TACACS key C!sc0TACACS
  B. tacacs server SITE6_TACACS key C!scoTACACS
  C. tacacs server SITE6_TACACS address ipv4 10.60.66.66 key C!scoTACACS
  D. tacacs server SITE6_TACACS address ipv4 10.66.66.66 key CiscoTACACS
  B. tacacs server SITE6_TACACS key C!scoTACACS