CCNA 3 Chapter 5 v6 Exam Answers

Which two events will trigger the sending of a link-state packet by a link-state routing protocol? (Choose two.)

An LSP (link-state packet) is only sent during initial startup of the routing protocol process on a router; and whenever there is a change in the topology, including a link going down or coming up, or a neighbor adjacency being established or broken. Data traffic congestion does not directly influence routing protocol behavior. LSPs are not flooded periodically, and update timers are not relevant to LSPs.

What happens when two link-state routers stop receiving hello packets from neighbors?

Hello packets serve a keepalive function to monitor the state of an adjacent router.

In the context of routing protocols, what is a definition for time to convergence?

Time to convergence defines how quickly the routers in the network topology share routing information and reach a state of consistent knowledge.

Which two components of an LSP enable an OSPF router to determine if the LSP that is received contains newer information than what is in the current OSPF router link-state database? (Choose two.)

Information such as sequence numbers and aging information is included in an LSP to help manage the flooding process. This information can assist a router in determining if it has already received the LSP from another router or if the LSP has newer information than what is already contained in the link-state database.

After a network topology change occurs, which distance vector routing protocol can send an update message directly to a single neighboring router without unnecessarily notifying other routers?

RIPv2 and EIGRP support updating neighboring routers via the use of multicasting. EIGRP is the only distance vector protocol that can support updating a specific neighbor by using unicast. OSPF and ISIS are link state protocols.

Which routing protocol is designed to use areas to scale large hierarchical networks?

OSPF works best for a large hierarchical network, because OSPF supports a multiarea design, which provides a much better scaling capability compared with EIGRP

Which routing protocol uses link-state information to build a map of the topology for computing the best path to each destination network?

OSPF is a link-state routing protocol and as such it uses a link-state database to construct a topology map of the network to calculate the best path to destination networks. RIP, RIPng, and EIGRP are distance vector routing protocols.

Refer to the exhibit. A network administrator has configured RIPv2 in the given topology. Which path would a packet take to get from the LAN that is connected to R1 to the LAN that is connected to R7?

RIP utilizes hop count to calculate the best path from source to destination.

What is a disadvantage of deploying OSPF in a large single area routing environment?

Link-state protocols have the following disadvantages: Memory Requirements – Creating and maintaining the link-state database and SPF tree.
Processing Requirements – The SPF algorithm requires more CPU time than distance vector algorithms because link-state protocols build a complete map of the topology.
Bandwidth Requirements – Link-state packet flooding can adversely affect the available bandwidth on a network.

What is the difference between interior and exterior routing protocols?

Interior gateway protocols (IGPs) are used for routing within an organization having a common administration or autonomous system (AS). Exterior gateway protocols (EGPs) are used by service providers and sometimes by large companies.

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A network administrator is researching routing protocols for implementation in a critical network infrastructure. Which protocol uses the DUAL algorithm to provide almost instantaneous convergence during a route failover?

EIGRP is commonly the fastest IGP to converge because it maintains alternate routes. A switchover to an alternate route is immediate and does not involve interaction with other routers.

Which feature provides secure routing updates between RIPv2 neighbors?

The RIPv2 routing protocol supports routing protocol authentication to secure routing table updates between neighbors.

Which dynamic routing protocol was developed as an exterior gateway protocol to interconnect different Internet providers?

BGP is a protocol developed to interconnect different levels of ISPs as well as ISPs and some of their larger private clients.

What is maintained within an EIGRP topology table?

The EIGRP topology table maintains all the routes received from neighbors, not just the best paths. DUAL can use backup routes from the topology table to provide instantaneous route failover in the EIGRP routing table.

Refer to the exhibit. OSPF is used in the network. Which path will be chosen by OSPF to send data packets from Net A to Net B?

OSPF uses the shortest path first algorithm to select the best path to forward packets. Each path is labeled with a value for cost and this algorithm accumulates costs along each path, from source to destination. The path chosen from Net A to Net B is R1-R3-R5-R7, that is equal to 5+7+14+2=28, the shortest cost.

Which statement is an incorrect description of the OSPF protocol?

Link-state protocols require more memory to create and maintain the link-state database.

Which two requirements are necessary before a router configured with a link-state routing protocol can build and send its link-state packets? (Choose two.)

Once a router has established its adjacencies, it can build its link-state packets (LSPs) that contain the link-state information, including the link cost. A router can only build a link-state after it has received link-state packets from adjacent routers. It then constructs its SPF tree from the least cost routes to remote networks which are used to populate its routing table.

Which routing protocol sends a routing update to neighboring routers every 30 seconds?

What is the first step taken by a newly configured OSPF router in the process of reaching a state of convergence?

Before OSPF can form a neighbor adjacency and start the Hello protocol, it detects which interfaces are in an up and active state.

Which two routing protocols are classified as distance vector routing protocols? (Choose two.)

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Match the features of link-state routing protocols to their advantages and disadvantages. (Not all options are used.)

What are two features of the OSPF routing protocol? (Choose two.)

Characteristics of OSPF include the following: Interior gateway protocol
Link-state
Classless
Cost metric based on bandwidth
Dijkstra algorithm
Builds topological map
Event-driven updates
Hierarchical design
Requires additional memory, CPU processing, and more initial bandwidth than other protocols

Which two protocols are link-state routing protocols? (Choose two.)

OSPF and IS-IS are link-state protocols. EIGRP and RIP are distance vector protocols.

An OSPF enabled router is processing learned routes to select best paths to reach a destination network. What is the OSPF algorithm evaluating as the metric?

The OSPF routing protocol uses the cumulative bandwidth as the metric for route computations.​

What are two purposes of dynamic routing protocols? (Choose two.)

The purpose of dynamic routing protocols include the following:
Discover remote networks
Maintain up-to-date routing information
Choose the best path to a destination network
Find a new best path if the current path is not available