Prepare 4A0-112 Question Answers - 4A0-112 Exam Dumps
Real Nokia 4A0-112 Exam Questions [Updated 2025]
Nokia 4A0-112 certification exam is a professional-level certification that focuses on the Nokia IS-IS routing protocol. 4A0-112 exam is designed for network professionals who are responsible for designing, configuring, and maintaining large-scale service provider networks. The Nokia IS-IS routing protocol is widely used in service provider networks to provide fast and efficient routing of IP packets. With this certification, network professionals can demonstrate their expertise in Nokia IS-IS routing protocol and their ability to deploy and manage large-scale service provider networks.
NEW QUESTION # 22
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?
- A. Every router that receives the new link-state advertisement updates its age field before forwarding it.
- B. If a router receives the new link-state advertisement, it acknowledges it, stores it, and forwards it to its own neighbors.
- C. If a router receives multiple copies of the new link-state advertisement, it will simply ignore all copies received after the first one.
- D. Every router that receives the new link-state advertisement runs the SPF algorithm to recalculate its shortest-path tree and its forwarding database.
Answer: A
Explanation:
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.
NEW QUESTION # 23
Which of the following statements about router interfaces on a Nokia 7750 SR is FALSE?
- A. The system interface exists by default.
- B. They can be assigned IPv4 and/or IPv6 addresses.
- C. They can be logical or physical.
- D. They can be used in pairs on the same subnet for redundancy.
Answer: D
Explanation:
Typically, interfaces on a Nokia 7750 SR router are not configured in pairs on the same subnet for redundancy. Instead, redundancy is achieved through mechanisms like Virtual Router Redundancy Protocol (VRRP) or other high availability protocols, not by simply using interfaces in pairs on the same subnet.
NEW QUESTION # 24
Two IS-IS routers are exchanging Hello packets. One is configured to use authentication and the other is not. Which of the following statements is TRUE?
- A. An adjacency will be established without authentication.
- B. An adjacency will not be established.
- C. An adjacency will be established with authentication using the default parameters defined for IS-IS routers.
- D. The two routers will negotiate the authentication parameters and the establish an adjacency.
Answer: B
Explanation:
IS-IS routers must have matching authentication settings to establish an adjacency. If one router is configured with authentication and the other is not, the routers will not be able to establish an adjacency because their authentication parameters do not match.
NEW QUESTION # 25
For a link-state routing protocol, which of the following statements about link-state updates is FALSE?
- A. Aging helps ensure that routers that are no longer part of the topology will eventually get removed from the link-state database.
- B. The age value is updated as the link-state update is flooded throughout the network and when it is in the link-state database
- C. When a router detects that a link-state update has reached its maximum age, it will request a new update from the source router.
- D. When a link-state update reaches its maximum age on a router, the router will flood that update to its neighbors.
Answer: D
Explanation:
When a link-state update reaches its maximum age, it is removed from the router's link-state database, not flooded to its neighbors. This prevents outdated information from continuing to affect the routing decisions. The router does not flood the aged update; instead, it will typically request a new link-state advertisement from the original source router if the information is still needed.
NEW QUESTION # 26
When using IS-IS in native mode for routing in a dual-stack IPv4/IPv6 environment, which of the following statements is FALSE?
- A. It may lead to traffic black-holing if not properly designed.
- B. All links are assumed to be IPv4- and IPv6-capable.
- C. The same topology information is used to calculate the shortest path tree for both IPv4 and IPv6.
- D. In a multi-area environment, the SPF algorithm needs to be run four times on each L1/L2 router.
Answer: D
Explanation:
In a dual-stack IPv4/IPv6 IS-IS environment, the SPF (Shortest Path First) algorithm is only run once per router for each protocol (IPv4 or IPv6). The topology is shared, but the SPF calculations for IPv4 and IPv6 are separate. This means that the SPF algorithm will run twice (once for IPv4 and once for IPv6) for each L1/L2 router, not four times.
NEW QUESTION # 27
Refer to the exhibit.
Routers R1 through R4 are running an IGP in such a way that they have each other's system IP addresses in their routing tables. A static route is configured on router R1 so that it can reach subnetwork 10.4.100.0/24. The network administrator decides to use an indirect static route, as shown in the diagram. However, pinging the server from router R1 fails. What may be the problem in this case?
- A. Router R3 drops the echo request because it does not have subnet 10.4.100.0/24 in its routing table.
- B. Router R2 drops the echo request because it does not have subnet 10.4.100.0/24 in its routing table.
- C. The echo request arrives at the server but there is no path for the echo response to return to router R1.
- D. Router R1 drops the echo request because address 10.10.10.3 does not belong to an adjacent router.
Answer: C
Explanation:
The static route configured on router R1 uses an indirect next-hop, which is 10.10.10.3 (R3). While the echo request from R1 reaches the server through the IGP, the problem lies in the return path for the echo response.
The route 10.4.100.0/24 is reachable through R3, but there is no reciprocal route in R3's routing table that allows the response to flow back towards R1. This results in a failure to return the echo response to R1, causing the ping to fail.
NEW QUESTION # 28
Refer to the exhibit.
Which of the following statements best describes the IS-IS domain to which the command output corresponds?
- A. Multi-area IS-IS domain with broadcast interfaces.
- B. Single-area IS-IS domain with broadcast interfaces.
- C. Single-area IS-IS domain with no broadcast interfaces.
- D. Multi-area IS-IS domain with no broadcast interfaces.
Answer: A
Explanation:
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.
NEW QUESTION # 29
Consider the exhibit.
All routers are running IS-IS with IPv6 support enabled. Based on the topology shown, and the route tables of routers R3 and R4, which of the following statements is TRUE?
- A. Route leaking is configured on both routers R1 and R2.
- B. Route leaking is configured on router R1 but not on router R2.
- C. There is no route leaking configured on router R1 or router R2.
- D. Route leaking is configured on router R2 but not on router R1.
Answer: A
Explanation:
Based on the IPv6 route table output for R3 and R4, we can see that the routers have remote routes listed as "Remote ISIS", indicating that the route is being advertised from a different area (area 49.01 or 49.02). This is a sign of route leaking, where routes from one area are being shared across areas.
The routes from R3 (level-1 router) are being advertised to R4 (level-1 router), and vice versa, with ISIS as the protocol. This implies that there is route leaking configured to allow information to pass between areas.
NEW QUESTION # 30
Refer to the exhibit.
In the diagram, all routers are using IS-IS as their routing protocol. The number next to each link is its metric value.
What path will traffic follow from router R6 to router R3, and from router R3 to router R6?
- A. Router R6 to router R3 will follow (R6-R5-R2-R3). Router R3 to router R6 will follow (R3-R4-R7-R5-R6).
- B. Router R6 to router R3 will follow (R6-R5-R2-R3). Router R3 to router R6 will follow (R3-R4-R2-R5-R6).
- C. Router R6 to router R3 will follow (R6-R5-R7-R4-R3). Router R3 to router R6 will follow (R3-R4-R7-R5-R6).
- D. Router R6 to router R3 will follow (R6-R5-R2-R3). Router R3 to router R6 will follow (R3-R2-R5-R6).
Answer: D
Explanation:
The metric values between the routers dictate the routing paths, and IS-IS will calculate the shortest path based on these values.
R6 to R3: The path from R6 to R3 will go through R5 and R2, as this route has the least cumulative metric (10 + 10 + 15 = 35).
R3 to R6: The reverse path from R3 to R6 will follow R3 → R2 → R5 → R6 because this route is also the shortest with a total metric of 10 + 10 + 10 = 30.
NEW QUESTION # 31
Refer to the exhibit.
All routers in the diagram are running an interior gateway protocol (IGP) and have been configured with an ECMP value of 4. Router R5 advertises the prefix 192.168.3.0/24 using the IGP. Assuming all links have the same cost, how many entries for prefix 192.168.3.0/24 will be in router R3's routing table?
- A. 0
- B. 1
- C. 2
- D. 3
Answer: D
Explanation:
In this scenario, the routers are configured with an Equal-Cost Multi-Path (ECMP) value of 4, meaning they can utilize up to 4 equal-cost paths to reach a destination. Since Router R5 is advertising the 192.168.3.0/24 prefix and all links have the same cost, router R3 will receive multiple routes to reach this destination.
Given that all the routers (R1, R2, R3, R4, and R5) are connected in a way that can support multiple equal-cost paths, and assuming ECMP is set to 4, the routing table on Router R3 will have up to 4 entries for the prefix 192.168.3.0/24.
Thus, Router R3's routing table will contain 4 entries for the prefix 192.168.3.0/24.
NEW QUESTION # 32
Which of the following statements about IS-IS is FALSE?
- A. IS-IS uses the concept of level-1 and level-2 routers to implement hierarchy.
- B. In IS-IS, routers are associated with an area, not the interfaces.
- C. A router becomes level-2 when it is associated with the backbone area.
- D. A level-1 router forwards traffic to other areas through the nearest I eve I-1/1 eve I-2 router.
Answer: B
Explanation:
In IS-IS, routers are actually associated with interfaces rather than the entire router being associated with a single area. A router can have interfaces in multiple areas, and it is the interface's configuration that determines which area it belongs to.
NEW QUESTION # 33
Which of the following is NOT a function of the control plane a router?
- A. To determine the best way to forward packets.
- B. To establish routing paths to deliver packets from source to destination and to reestablish them in case of failure.
- C. To exchange signaling messages with other routers.
- D. To utilize the forwarding tables to forward data packets towards their destination.
Answer: D
Explanation:
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.
NEW QUESTION # 34
What is the replacement for ARP in IPv6?
- A. Neighbor discovery procedures.
- B. Stateless address auto-configuration procedures.
- C. Duplicate address detection procedures.
- D. Router discovery procedures.
Answer: A
Explanation:
In IPv6, the Neighbor Discovery Protocol (NDP) replaces the Address Resolution Protocol (ARP) used in IPv4. NDP is responsible for several functions, including resolving IP addresses to MAC addresses (similar to ARP), detecting duplicate IP addresses, and discovering other devices on the network.
NEW QUESTION # 35
Refer to the exhibit.
All routers in the diagram are running a link-state routing protocol. Before the link failure, all routers have operational adjacencies with each other and there is a BFD session between routers R1 and R3. After the link failure, which of the following affects the routing protocol's convergence time?
- A. The time taken by the switches to detect that the physical ports are down.
- B. The value of the routing protocol hello timers on routers R1 and R3.
- C. The value of the BFD transmit interval, receive interval and multiplier settings on routers R1 and R3.
- D. The value of the Ethernet hello timers on the switches.
Answer: C
Explanation:
BFD (Bidirectional Forwarding Detection) is used to detect link failures quickly and helps improve convergence time in link-state routing protocols. The BFD session between routers R1 and R3 allows them to detect the failure of the link between them more quickly than the regular routing protocol hello timers. The transmit interval, receive interval, and multiplier settings determine how fast BFD detects a failure and triggers the routing protocol to converge, which directly impacts the convergence time.
NEW QUESTION # 36
Refer to the exhibit.
Static routing is to be used in a network between a corporate head office and a branch office. The head office has many connected subnetworks, whereas the branch office has one subnetwork and a single connection to the head office. Which of the following is the most likely configuration on the head office and branch office routers?
- A. The head office has a specific static route and the branch office has a default route.
- B. The head office and the branch offices both have specific static routes.
- C. The head office has a default route and the branch office has a specific static route.
- D. The head office and the branch office both have default routes.
Answer: C
Explanation:
The head office has many connected subnetworks, so it will typically have a default route to forward traffic to the branch office (or external networks), since it may not need to define static routes for each branch network.
The branch office, which has only one subnetwork and a single connection to the head office, will have a specific static route to reach the head office subnet or other subnets at the head office, since it only needs to know the specific route to reach the head office's network.
NEW QUESTION # 37
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?
- A. The equal cost multipath configuration
- B. The routing table manager (RTM)
- C. The forwarding information base (FIB)
- D. The routing information base (RIB)
Answer: B
Explanation:
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.
NEW QUESTION # 38
There are several differences between IS-IS Hello packets used on broadcast interfaces and on point-to-point interfaces.
Which of the following statements is FALSE?
- A. The neighbors are identified using their interface MAC addresses on broadcast Hello messages and using their system IDs on point-to-point Hello messages.
- B. Broadcast Hello messages identify the elected designed IS (DIS) and point-to-point Hello messages do not.
- C. On broadcast interfaces there are different Hello packet types for level-1 and level-2 adjacencies, whereas on point-to-point interfaces there is a single Hello packet type.
- D. The multicast MAC addresses to which the Hello messages are sent are different on broadcast interfaces and on point-to-point interfaces.
Answer: A
NEW QUESTION # 39
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Nokia 4A0-112 exam covers a range of topics related to the IS-IS protocol, including its design, configuration, and operation in a network environment. Candidates will be expected to have a deep understanding of IS-IS features and functionality, as well as the ability to troubleshoot common issues that may arise in IS-IS networks. In addition, the exam will test candidates' knowledge of related technologies such as IP routing, MPLS, and BGP.
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