Cisco CCNP Enterprise 300-410 Questions & Answers

• Question 841:

  Which method changes the forwarding decision that a router makes without first changing the routing table or influencing the IP data plane?

  A. nonbroadcast multiaccess

  B. packet switching

  C. policy-based routing

  D. forwarding information base

  Correct Answer: C

• Question 842:

  Refer to the exhibit. The output of the trace route from R5 shows a loop in the network. Which configuration prevents this loop?

  

  

  

  A. Option A

  B. Option B

  C. Option C

  D. Option D

  Correct Answer: A

• Question 843:

  Refer to the exhibit. An engineer configures a static route on a router, but when the engineer checks the route to the destination, a different next hop is chosen. What is the reason for this?

  

  A. Dynamic routing protocols always have priority over static routes.

  B. The metric of the OSPF route is lower than the metric of the static route.

  C. The configured AD for the static route is higher than the AD of OSPF.

  D. The syntax of the static route is not valid, so the route is not considered.

  Correct Answer: C

  The AD of static route is manually configured to 130 which is higher than the AD of OSPF router which is 110.

• Question 844:

  DRAG DROP

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

  Select and Place:

  

  Correct Answer:

  

  

  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

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

• Question 845:

  How are CE advertised routes segmented from other CE routers on an MPLS PE router?

  A. with a combination of VRF-Lite and MP-BGP

  B. by pushing MPLS labels advertised by LDP on customer routes

  C. by enabling multiple instances of BGP, one for each CE router

  D. by assigning CE-facing interfaces to different VRFs

  Correct Answer: D

  In an MPLS (Multiprotocol Label Switching) network, Customer Edge (CE) routers are typically connected to Provider Edge (PE) routers. To keep the routes from different CE routers segregated on the PE router, Virtual Routing and Forwarding (VRF) is commonly used. Each VRF acts as a separate routing table, effectively isolating routes from one CE router from routes of another CE router.

• Question 846:

  Which Layer 3 VPN attribute installs customer routes in the VRF?

  A. RD

  B. RT

  C. extended-community

  D. MPLS label

  Correct Answer: B

• Question 847:

  Refer to the exhibit.

  

  R3 is learning the 1.0.0.0/24 route through OSPF instead of EIGRP. Which action causes R3 to choose EIGRP to reach the 1.0.0.0/24 network?

  A. Configure EIGRP administrative distance to 120.

  B. Configure EIGRP administrative distance to 110.

  C. Configure OSPF administrative distance to 120.

  D. Configure OSPF administrative distance to 200.

  Correct Answer: D

  Must make OSPF AD more than EIGRP External 170

• Question 848:

  Refer to the exhibit.

  

  It was noticed that after NetFlow is configured in the router, the collector stopped receiving flow information. Which action resolves the issue?

  A. Apply the ip flow egress command to the loopback2 interface.

  B. Modify the source through the ip flow-export source loopback1 command.

  C. Configure an IP address on the loopback2 interface to use as a source.

  D. Change the IP address of the loopback 2 interface to a public IP address.

  Correct Answer: B

• Question 849:

  Refer to the exhibit.

  

  R1 should receive 10.16.2.0/24 from R2. Which action resolves the issue?

  A. Add prefix-list seq 1 on R1 to permit 10.16.0.0/22.

  B. Add prefix-list seq 1 on R1 to permit 10.16.2.0/24.

  C. Modify prefix-list seq 5 on R2 to permit 10.16.0.0/22.

  D. Modify prefix-list seq 5 on R2 to permit 10.16.0.0/23.

  Correct Answer: C

• Question 850:

  Refer to the exhibit.

  

  The primary link between R1 and R2 went down, but R3 is still advertising the 192.168.200.0/24 network to R1 and the 192.168.100.0/24 network to R2, which creates a loop. Which action resolves the issue?

  A. Configure the eigrp stub command under the EIGRP process on R2.

  B. Configure the summary-address 192.168.0.0 255.255.0.0 100 command on R3.

  C. Configure the eigrp stub command under the EIGRP process on R3.

  D. Configure the eigrp stub leak-map command under the EIGRP process on R1.

  Correct Answer: C