View Full Cisco CCNP 300-415 Exam Dumps and Practice Test Dumps.

 

Question 41

Which EIGRP feature allows a router to advertise a summary route instead of multiple specific routes?

1. Route filtering
2. Route summarization
3. Split horizon
4. Stub routing

Correct Answer: 2

Explanation

EIGRP route summarization allows a router to advertise a summarized network prefix instead of multiple individual routes. This can significantly reduce the amount of routing information exchanged between routers and can make the routing table smaller. Summarization can also limit the scope of EIGRP queries and improve network stability by hiding specific topology changes from other parts of the network. EIGRP supports manual summarization on interfaces, allowing administrators to define the summary prefix that should be advertised. Proper summarization requires careful address planning to avoid accidentally creating black holes. It is particularly useful in hierarchical enterprise network designs.

Question 42

Which OSPF command displays information about the OSPF link-state database?

1. show ip ospf database
2. show ip ospf neighbor
3. show ip route ospf
4. show ip protocols

Correct Answer: 1

Explanation

The show ip ospf database command displays the OSPF link-state database maintained by the router. The output can contain different LSA types, including Router LSAs, Network LSAs, Summary LSAs, ASBR Summary LSAs, and AS External LSAs depending on the router’s role and OSPF topology. This information is useful for verifying whether OSPF routers have learned the expected topology information. Administrators can use additional command options to examine specific LSA types or areas. The neighbor command focuses on adjacency states, while the routing-table command shows installed OSPF routes. The database command is therefore an important troubleshooting tool for OSPF topology problems.

Question 43

Which BGP attribute is normally assigned to routes that are originated locally using a network statement?

1. Incomplete origin
2. EGP origin
3. IGP origin
4. External origin

Correct Answer: 3

Explanation

Routes introduced into BGP using a network statement are normally assigned an IGP Origin attribute. In BGP terminology, the IGP origin is represented by the value “i” and is generally preferred over EGP and Incomplete origins during the relevant stage of best-path selection. An Incomplete origin commonly indicates that a route entered BGP through redistribution. The Origin attribute is only one component of the BGP best-path algorithm and is considered after several other attributes. Understanding how routes receive their Origin values helps administrators troubleshoot differences between paths and understand why one BGP route may be preferred over another.

Question 44

Which OSPF router is responsible for generating Type 3 LSAs between areas?

1. ASBR
2. ABR
3. DR
4. BDR

Correct Answer: 2

Explanation

An Area Border Router, or ABR, generates Type 3 Summary LSAs to advertise networks from one OSPF area into another. ABRs maintain link-state information for the areas to which they are connected and provide the inter-area connectivity required by the OSPF hierarchical architecture. Type 3 LSAs allow routers to learn about networks outside their local area without receiving the complete topology database of every other area. An ASBR has a different function because it introduces external routes into OSPF. DR and BDR roles are primarily associated with multiaccess network segments. Proper ABR operation is therefore important for inter-area route propagation.

Question 45

Which EIGRP metric value is normally accumulated across all links along a path?

1. Delay
2. Bandwidth
3. MTU
4. Reliability

Correct Answer: 1

Explanation

EIGRP accumulates interface delay values across all links in a route when calculating its composite metric. The total delay represents the cumulative delay of the path and contributes to route selection along with bandwidth under the default EIGRP metric configuration. Bandwidth is treated differently because EIGRP uses the minimum bandwidth along the path rather than simply adding bandwidth values from each interface. MTU is carried in EIGRP topology information but is not part of the default metric calculation. Reliability can be included if the appropriate K values are configured, although this is not the default behavior. Understanding metric components is important for predicting EIGRP path selection.

Question 46

Which BGP command provides detailed information about a specific BGP neighbor?

1. show ip bgp
2. show ip bgp summary
3. show ip bgp neighbors
4. show ip route

Correct Answer: 3

Explanation

The show ip bgp neighbors command provides detailed information about BGP peer relationships. It can display session state, remote autonomous system information, timers, capabilities, message counters, prefixes received, prefixes advertised, and other operational details. Administrators can use this command when investigating BGP session problems or determining whether routes are being exchanged correctly with a particular peer. The show ip bgp summary command provides a shorter overview of all neighbors, while show ip bgp displays the BGP routing table. Detailed neighbor information is particularly useful when troubleshooting route policies, authentication, capabilities, and session establishment issues.

Question 47

Which OSPF packet is responsible for discovering neighboring routers?

1. Database Description
2. Hello
3. Link-State Update
4. Link-State Acknowledgment

Correct Answer: 2

Explanation

OSPF Hello packets are responsible for discovering neighboring OSPF routers and maintaining neighbor relationships. Routers periodically send Hello packets through OSPF-enabled interfaces. These packets contain information such as the router ID, area ID, timers, network mask, and other parameters used to determine whether neighboring routers are compatible. If the required parameters match, the routers can establish a neighbor relationship and proceed through the OSPF adjacency states. Hello packets also help detect failed neighbors when expected messages are no longer received within the configured dead interval. This makes Hello packets fundamental to OSPF neighbor discovery and adjacency maintenance.

Question 48

Which EIGRP packet is sent in response to a Query packet?

1. Reply
2. Update
3. Hello
4. Acknowledgment

Correct Answer: 1

Explanation

EIGRP Reply packets are sent in response to Query packets. When an EIGRP router loses its successor and does not have a feasible successor, it can enter an active state and query neighboring routers for alternative paths. Neighboring routers process the query and respond with Reply packets indicating whether they have a valid route to the destination. The originating router uses these responses as part of the DUAL process to determine the next available loop-free path. Excessive query propagation can create convergence problems in large networks, which is why techniques such as route summarization and EIGRP stub routing are commonly used.

Question 49

Which BGP attribute is exchanged between eBGP peers and is used to identify the path length through autonomous systems?

1. Local Preference
2. Weight
3. AS Path
4. MED

Correct Answer: 3

Explanation

The AS Path attribute records the autonomous systems that a BGP route has traversed. When an autonomous system advertises a route to an external BGP neighbor, its AS number is normally added to the AS Path. This information allows routers to identify routing loops because a route containing the local AS number can be rejected. AS Path length is also considered during BGP best-path selection, with shorter paths generally preferred when higher-priority attributes are equal. Administrators can manipulate AS Path using techniques such as AS-path prepending to influence inbound traffic decisions made by external networks. It is therefore important for both routing-loop prevention and policy control.

Question 50

Which OSPF LSA type is generated by a DR on a multiaccess network?

1. Type 1
2. Type 2
3. Type 3
4. Type 5

Correct Answer: 2

Explanation

OSPF Type 2 LSAs, known as Network LSAs, are generated by the Designated Router on multiaccess network segments such as Ethernet networks. The Type 2 LSA describes the routers connected to that shared network segment and identifies the DR as the originating router. This mechanism reduces the amount of OSPF adjacency information that would otherwise be required if every router on a multiaccess segment had to establish a full adjacency with every other router. Type 1 LSAs describe individual routers, Type 3 LSAs advertise networks between areas, and Type 5 LSAs represent external routes. DR operation is therefore closely associated with Type 2 LSAs.

Question 51

Which BGP attribute is propagated throughout an autonomous system and normally has a higher value preference?

1. Local Preference
2. MED
3. Origin
4. AS Path

Correct Answer: 1

Explanation

Local Preference is a BGP attribute used within an autonomous system to influence the preferred exit point for outbound traffic. It is normally propagated to internal BGP peers, allowing multiple routers to apply a consistent routing policy. When comparing otherwise suitable paths, BGP generally prefers the route with the higher Local Preference value. This differs from MED, where a lower value is generally preferred. Local Preference is not normally advertised to external BGP peers. Administrators commonly use route maps to modify Local Preference based on route characteristics, neighbor relationships, or business policies. It is therefore a key attribute for controlling outbound traffic across multiple external connections.

Question 52

Which OSPF area type allows an ASBR to redistribute external routes while using Type 7 LSAs?

1. Stub area
2. Totally stubby area
3. NSSA
4. Backbone area

Correct Answer: 3

Explanation

A Not-So-Stubby Area, or NSSA, allows an OSPF ASBR to introduce external routes while keeping Type 5 LSAs out of the area. External routes redistributed by the ASBR are represented using Type 7 LSAs within the NSSA. An ABR can translate appropriate Type 7 LSAs into Type 5 LSAs when the external routes need to be advertised into other OSPF areas. This provides a useful combination of external route redistribution and reduced external LSA flooding. Stub and totally stubby areas do not allow an internal ASBR to introduce external routes in the same way. NSSA is therefore useful for specific hierarchical OSPF designs.

Question 53

Which command displays EIGRP neighbor relationships for IPv4?

1. show ip eigrp topology
2. show ip eigrp neighbors
3. show ip route eigrp
4. show ip protocols

Correct Answer: 2

Explanation

The show ip eigrp neighbors command displays information about EIGRP neighbor relationships. The output typically includes the neighbor’s address, interface, hold time, uptime, sequence information, and the EIGRP topology table version. This command is useful when verifying whether EIGRP routers have successfully established neighbor relationships. If a neighbor is missing, administrators can investigate interface configuration, autonomous system numbers, network statements, authentication, K values, and connectivity. The topology command provides route information rather than the primary neighbor table, while the routing command displays installed routes. Checking the EIGRP neighbor table is often an important first step when troubleshooting EIGRP adjacency problems.

Question 54

Which BGP state indicates that the BGP session has been successfully established?

1. Active
2. OpenSent
3. Established
4. Idle

Correct Answer: 3

Explanation

The Established state indicates that a BGP session has successfully completed the required negotiation and that the peers can exchange routing information. During session establishment, BGP progresses through states such as Idle, Connect, Active, OpenSent, OpenConfirm, and finally Established. Once established, Update messages can be exchanged to advertise or withdraw routes. If a session remains in Idle or Active, administrators should investigate connectivity, TCP port 179 access, autonomous system configuration, router IDs, authentication, and other parameters. The show ip bgp summary command is commonly used to identify the current state of BGP peers and determine whether the session has reached the Established state.

Question 55

Which OSPF algorithm calculates the shortest path tree?

1. DUAL
2. SPF
3. Bellman-Ford
4. Path Vector

Correct Answer: 2

Explanation

OSPF uses the Shortest Path First algorithm, commonly associated with Dijkstra’s algorithm, to calculate the shortest path tree from the perspective of each router. The calculation is based on the link-state information contained in the OSPF database. Each router independently builds its shortest path tree and uses the resulting information to determine the best routes. OSPF’s link-state approach allows routers to maintain a detailed view of the network topology within their areas. EIGRP uses DUAL, while BGP uses a path-vector approach. Understanding SPF calculations is important when analyzing OSPF convergence, route selection, and the effects of topology changes.

Question 56

Which EIGRP value represents the metric advertised by a neighboring router to reach a destination?

1. Feasible Distance
2. Reported Distance
3. Composite Metric
4. Administrative Distance

Correct Answer: 2

Explanation

Reported Distance, also called Advertised Distance in some EIGRP terminology, represents the metric that an EIGRP neighbor reports for reaching a particular destination. EIGRP uses this value as part of the feasibility condition when determining whether an alternate route can become a feasible successor. The Feasible Distance represents the best-known metric from the local router to the destination. If a neighbor’s Reported Distance is lower than the local Feasible Distance, the path can satisfy the feasibility condition. These values are visible in EIGRP topology information and are important for understanding how DUAL evaluates alternate paths and maintains loop-free routing.

Question 57

Which BGP attribute is used only on the local router and is not advertised to BGP peers?

1. Weight
2. Local Preference
3. MED
4. Origin

Correct Answer: 1

Explanation

Weight is a Cisco-specific BGP attribute that is applied locally and is not advertised to BGP peers. A higher Weight value is preferred when a Cisco router selects between multiple BGP paths. Because the attribute remains local, changing Weight on one router does not directly change the path-selection behavior of other routers in the autonomous system. This makes Weight useful when an administrator wants to influence routing decisions on a specific router. Local Preference is more appropriate when a policy should influence multiple routers through iBGP. Understanding the scope of BGP attributes is important when designing predictable routing policies.

Question 58

Which OSPF state occurs when routers have discovered each other but have not yet established full database synchronization?

1. Full
2. Loading
3. 2-Way
4. Exchange

Correct Answer: 3

Explanation

The OSPF 2-Way state indicates that two routers have successfully discovered each other and have established bidirectional communication. On broadcast networks, not every router necessarily progresses to a Full adjacency with every other router. Routers may remain in the 2-Way state with each other when they are not selected as the DR or BDR relationship. The routers continue to communicate through the DR and BDR as required. On point-to-point links, routers normally proceed beyond 2-Way toward database synchronization. Understanding the 2-Way state helps administrators distinguish normal OSPF behavior from an actual adjacency problem.

Question 59

Which routing protocol uses TCP port 179 for establishing routing sessions?

1. OSPF
2. EIGRP
3. BGP
4. IS-IS

Correct Answer: 3

Explanation

BGP uses TCP port 179 to establish reliable sessions between BGP peers. Using TCP provides BGP with reliable, ordered delivery of routing information without requiring BGP itself to implement a separate transport reliability mechanism. When troubleshooting a BGP session, administrators should verify IP connectivity and ensure that TCP port 179 is not being blocked by an access control list, firewall, or other security mechanism. OSPF operates directly over IP protocol 89, while EIGRP also uses its own IP protocol rather than TCP. Understanding BGP’s use of TCP port 179 is fundamental when diagnosing session-establishment and connectivity problems.

Question 60

Which OSPF mechanism allows an administrator to summarize routes at an area boundary?

1. ABR route summarization
2. Split horizon
3. EIGRP stub routing
4. BGP aggregation

Correct Answer: 1

Explanation

OSPF allows an Area Border Router to summarize routes between areas, reducing the number of individual prefixes advertised across an area boundary. This process is commonly configured using area range commands on an ABR. Route summarization can reduce the size of routing tables and limit the propagation of detailed topology information. It can also improve network stability because changes to individual routes inside a summarized range may not need to be advertised outside the area. Administrators should carefully plan summary ranges to avoid creating unreachable destinations or unexpected routing behavior. Proper OSPF summarization is particularly useful in large hierarchical networks.