Nokia 4A0-112 Exam Practice Test Instant Access

Question 1

Which of the following is NOT a required configuration step to successfully run IS-IS on a router?

AThe router needs to be associated with an IS-IS area ID.

BLayer-3 interfaces that will participate in IS-IS need to be identified.

CA reference bandwidth needs to be configured to calculate link costs.

DThe IS-IS context needs to be enabled.

Answer : C

While configuring a reference bandwidth (which is used to calculate link costs) can be useful, it is not strictly required for IS-IS to run. IS-IS uses default bandwidth values to calculate costs, and it can function without explicitly configuring a reference bandwidth.

Question 2

When a router performs the SPF calculation, which router is used as the root of the shortest path tree?

AThe router with the fewest links.

BThe router with the lowest router ID.

CThe router's closest neighbor.

DThe router doing the calculation.

Answer : D

When a router performs the SPF (Shortest Path First) calculation, it uses itself as the root of the shortest path tree (SPT). This router computes the shortest paths to all other routers in the network, treating itself as the origin and calculating the paths based on its view of the network.

Question 3

A router is trying to establish an IS-IS adjacency with the DIS on a broadcast link. What event causes the adjacency to change from ''Initializing'' to ''UP''?

AReceiving a Hello packet from the DIS that contains the local router's own MAC address in the neighbor list.

BReceiving the first CSNP packet from the DIS that lists the LSPs in the DIS's link-state database.

CReceiving a CSNP packet from the DIS acknowledging the last transmitted LSP.

DReceiving the last LSP requested from the DIS.

Answer : B

The process of establishing an IS-IS adjacency on a broadcast link involves several steps, and the transition from the Initializing state to the UP state occurs when both routers exchange sufficient information to confirm they have a consistent view of the link-state database.

The CSNP (Complete Sequence Number PDU) packet is used to advertise the list of LSPs in the router's link-state database. When a router receives the first CSNP from the DIS (Designated Intermediate System) that lists the LSPs in the DIS's database, it indicates that the router has enough information to establish the adjacency and synchronize its database.

Question 4

Which of the following is NOT a function of the control plane a router?

ATo exchange signaling messages with other routers.

BTo determine the best way to forward packets.

CTo establish routing paths to deliver packets from source to destination and to reestablish them in case of failure.

DTo utilize the forwarding tables to forward data packets towards their destination.

Answer : D

The data plane (or forwarding plane) is responsible for actually forwarding the data packets. It uses the information stored in the forwarding table to determine how to move packets from one interface to another toward their destination.

Question 5

A router running a link-state routing protocol detects that one of its neighbors is no longer connected to it. The router generates a new link-state advertisement to inform other routers of the topology change. Which of the following is NOT an action that is triggered by this event?

AIf a router receives the new link-state advertisement, it acknowledges it, stores it, and forwards it to its own neighbors.

BIf a router receives multiple copies of the new link-state advertisement, it will simply ignore all copies received after the first one.

CEvery router that receives the new link-state advertisement updates its age field before forwarding it.

DEvery router that receives the new link-state advertisement runs the SPF algorithm to recalculate its shortest-path tree and its forwarding database.

Answer : C

When a router receives a link-state advertisement (LSA), it does not update the age field before forwarding it. The age field in an LSA is typically updated by the originating router or during the process of forwarding the LSA within the network. Routers do not modify the age field upon receiving and forwarding an LSA.

Question 6

When multiple routing protocols offer a route for the same prefix, what part of the router is in charge of deciding which route to make active?

AThe routing information base (RIB)

BThe routing table manager (RTM)

CThe equal cost multipath configuration

DThe forwarding information base (FIB)

Answer : B

The routing table manager (RTM) is responsible for selecting the best route when multiple routing protocols provide a route for the same destination prefix. It makes the decision on which route to add to the routing table based on the administrative distance, metric, and other criteria.

Question 7

Refer to the exhibit.

Which of the following statements best describes the IS-IS domain to which the command output corresponds?

ASingle-area IS-IS domain with no broadcast interfaces.

BMulti-area IS-IS domain with no broadcast interfaces.

CSingle-area IS-IS domain with broadcast interfaces.

DMulti-area IS-IS domain with broadcast interfaces.

Answer : D

The output shows two levels of IS-IS databases: Level 1 (L1) and Level 2 (L2). This indicates that the domain is multi-area, as L1 routers are confined to a single area, while L2 routers can route between different areas. The presence of Level 1/Level 2 (L1/L2) routers also suggests that the domain spans multiple areas.

The LSP (Link-State PDU) entries show L1/L2 ATT attributes, which typically indicate that these routers are capable of routing both within their own area (Level 1) and across areas (Level 2), suggesting a multi-area design.

The IS-IS domain likely includes broadcast interfaces, as indicated by the 'ATT' attribute (typically referring to the type of interface) and common IS-IS configuration practices on broadcast networks like Ethernet.

Nokia 4A0-112 Nokia IS-IS Routing Protocol Exam Practice Test