4A0-113 Sample Questions Answers

Area Border Router

Autonomous System Boundary Router

Designated Router

All routers within an OSPF area.

configure router static-route 139.120.121.0/24 next-hop 138.120.199.2

configure router static-route 139.120.121.0/24 next-hop 138.120.199.1

configure router static-route 138.120.199.2/24 next-hop 138.120.199.1

configure router static-route 139.120.121.0/24 next-hop 139.120.121.2

True

False

Router R1 generates a type 5 LSA that is flooded through all OSPF areas.

Router R1 generates a type 7 LSA that is flooded through all OSPF areas.

Router R1 generates a type 5 LSA that is flooded through area 1. Router R2 generates a type 7 LSA that is flooded through areas 0 and 2.

Router R1 generates a type 7 LSA that is flooded through area 1. Router R3 generates a type 5 LSA that is flooded through areas 0 and 2.

When two areas need to communicate and there is no area 0.

When an area needs to traverse another area to reach area 0.

When two areas are connected to area 0, but there is no direct path between them.

When an area needs to connect directly to another area without using area 0.

Area ID W B.

Hello and Dead intervals PC.

Stub flag

Checksum values

The list of neighbors

When a Link State Update is received in response to a Link State Request

When a router receives a Hello packet from a neighbor that contains its router id in the neighbor list

When OSPF neighbors exchange Database Descriptor packets

When a Link State Acknowledgement is received in response to a Link State Update

An OSPF type 3 LSA is an intra-area LSA, generated by the ABR only when route summarization is configured.

An OSPF type 3 LSA is an inter-area LSA, generated by the ABR only when route summarization is configured.

An OSPF type 3 LSA is an inter-area LSA, generated by an ASBR to describe external routes.

An OSPF type 3 LSA is an inter-area LSA, generated by the ABR to describe a route to neighbors outside the area.

The term backbone router has the same definition as the term area border router.

An OSPF network needs at least one area border router to function.

Area border routers connect the backbone area to other areas in an OSPF network.

By definition, an area border router must perform route summarization between areas.

Source IP address

TCP source port

Prefix list

Protocol type

On a point-to-point link, there is no need for a DR and BDR election; all routing updates are sent to 224.0.0.5.

On a point-to-point link, a DR and BDR are elected. The DR sends link-state advertisements describing the network.

On a point-to-point link, a DR and BDR are elected. To ensure resiliency, both the DR and BDR send link-state advertisements describing the network.

On a point-to-point link, there is no need for a DR and BDR election. All routing updates are sent to the unicast address of the neighbor's interface.

Default path

Default gateway

Gateway path

Proxy ARP

The adjacency state is two way because both routers have received a database description packet.

The adjacency is in the exchange state. The next step is to exchange link state request and link state update packets.

The adjacency is in the ex start state. The routers have exchanged database description packets, but still have to negotiate the starting sequence number.

The adjacency state is full. The routers are exchanging database description packets to notify each other that all link state advertisements have been received.

Hop count and 16

Hop count and 15

Link cost and 15

Link cost and 16

Neighbor, adjacency, route table

Neighbor, topology, forwarding

Topology, routing, forwarding

There are only two databases: adjacency and topology

MD5 Authentication is not supported.

Router LSAs do not carry IPv6 prefix information

NSSA is not supported in OSPFv3.

OSPFv3 uses a 32-bit router ID.

The MTU does not match on both interfaces.

OSPF is not enabled on one of the routers.

The router ID is the same on both routers.

An OSPF Hello has not been received from the neighbor.

The interfaces are configured as point-to-point on one side and broadcast on the other.

A policy statement within the router identifying what is to be advertised

Access-lists denoting what is to be advertised

Default metrics for each link

A group and neighbor statement for each peer

Full; both routers are exchanging Helios to maintain the adjacency.

The adjacency is down.

The adjacency is in exstart state.

The adjacency is in the exchange state.

The router sends a link-state update to its neighbor.

The router sends a link-state acknowledgement to its neighbor.

The router updates the information in its LSDB with the information received from its neighbor.

The router sends a link-state request to its neighbor.

The router takes no action.

30 second network updates

Classless routing

Broadcast advertisement

Poison Reverse

From the last 32 bits of the chassis MAC address

From the first 32 bits of the chassis MAC address

The loopback IP address

By using the command "config router ospf rid X.X.X.X"

From the system IP address

From the highest interface IP address

Convergence is triggered when the adjacency between routers R1 and R2 drops as a result of Hello timeouts. At this point, both routers R1 and R2 re-compute their link state database and send updates to their adjacent routers. Once the process is complete for all routers, the networks have converged.

Convergence is triggered when the physical interfaces between routers R1 and R2 go down. At this point, both routers R1 and R2 re-compute their link state database and send updates to their adjacent routers. Once the process is complete for all routers, the networks have converged.

Convergence will not be triggered because switches cannot run routing protocols between them.

Convergence is triggered when the switches notify the routers about the link state information. At this point, both routers R1 and R2 re-compute their link state database and send updates to their adjacent routers. Once the process is complete for all routers, the networks have converged

Convergence is triggered when an LSA is sent from router R1 to router R2 to indicate that the link is down. At this point, both routers R1 and R2 re-compute their link state database and send updates to their adjacent routers. Once the process is complete for all routers, the networks have converged.

Use split horizon by default.

Send information about directly connected links to neighbors at periodic intervals.

Use holddown timers when topologies change to allow for convergence.

Maintain multiple databases: neighbor, topology and routing.

5 and 15 seconds

10 and 30 seconds

5 and 20 seconds

10 and 40 seconds

Fast reroute capability

Control traffic prioritization

Route redistribution

Traffic engineering extensions

Cut through forwarding

The age for newly created link state information is set to 0 for OSPF and 1200 for IS-IS

The age for newly created link state information is set to 1200 for OSPF and 0 for IS-IS

The age is incremented or decremented as it is flooded from router to router and as it is held in the topological database.

The age is incremented or decremented only as it is held in the topological database and not as it is flooded router to router.