Chapter 9 - Multiarea OSPF

D) terminated stub area

A regular area can have a number of subtypes. Which of the following is not a regular area subtype? A) standard area B) stub area C) totally stubby area D) terminated stub area E) not-so-stubby area

C) Large adjacency table

According to the curriculum, which of the following is NOT an issue facing very large areas in Single Area OSPF? A) Large routing table B) Frequent SPF algorithm calculations C) Large adjacency table D) Large link-state database

C) a transit area

An OSPF area whose primary function is the fast and efficient movement of IP packets is referred to as what? A) area 1 B) a non-backbone area C) a transit area D) a regular area

B) a non-backbone area

An OSPF area whose primary function is to connect users and resources is referred to as what? A) a backbone area B) a non-backbone area C) a transit area D) area 0

regular (non-backbone)

By default, a __________________________ area does not allow traffic from another area to use its links to reach other areas.

D) Area Border This is a router that has interfaces attached to multiple areas. It must maintain separate LSDBs for each area it is connected to and can route between areas.

In MA OSPF, this is a router which transmits information from the local area. A) Autonomous System Boundry Router (ASBR) B) Backbone Router C) Internal Router D) Area Border Router (ABR)

D) SPF algorithm

In a large network, changes are inevitable, so the routers spend many CPU cycles recalculating the ___________________________ and updating the routing table. A) Neighbor adjacencies B) Area boundary ID C) LSDB D) SPF algorithm

A) memory

Multiarea OSPF is useful in larger network deployments to reduce processing and ___________________________ overhead. A) memory B) CPU C) bandwidth D) cost

A) Type 1 All routers advertise their directly connected OSPF-enabled links in a Type 1 LSA and forward their network information to OSPF neighbors.

The ____________________ LSA contains a list of the directly connected interfaces, link types, neighbors, and link states. A) Type 1 B) Type 2 C) Type 3 D) Type 4 E) Type 5

area 0

The backbone area is also called OSPF __________________________?

B) Internal Router An internal router has all of its interfaces in the same area. All internal routers in an area have identical LSDBs

This is a router that has all of its interfaces in the same area. A) Backbone Router B) Internal Router C) Area Border Router (ABR) D) Autonomous System Boundry Router (ASBR)

D) Autonomous System Boundry Router (ASBR) An external network is a network that is not part of this OSPF routing domain. For example, a network connection to an ISP. An ASBR can import external network information to the OSPF network, and vice versa, using a process called route redistribution

This is a router that has at least one interface attached to an external internetwork. A) Backbone Router B) Internal Router C) Area Border Router (ABR) D) Autonomous System Boundry Router (ASBR)

C) LSDB

Too many routers in one area make the ___________________________ larger and increase the load on the CPU. A) Routing table B) DBD packet size C) LSDB D) Forwarding database

E) interarea traffic

Traffic between OSPF areas via a backbone area is referred to as what? A) transarea traffic B) latent-area communication (LAC) C) cross-area traffic D) intra-area traffic E) interarea traffic

False. A router can be classified as more than one router type. For example, if a router connects to area 0 and area 1, and in addition maintains routing information for external networks, it falls under three different classifications: a backbone router, an ABR, and an ASBR.

True or False A router can be classified as only one router type. For example, if a router connects to area 0 and area 1, and in addition maintains routing information for external networks, it is classified as an ASBR only.

True. ABRs distribute the routing information into the backbone. The backbone routers then forward the information to the other ABRs.

True or False ABRs can be configured to summarize the routing information from the LSDBs of their attached areas.

True.

True or False According to the curriculum, too many routers in one area increases the load on the CPU and create a large link-state database, making Multiarea OSPF preferable.

False An OSPF area is a group of routers that share the same link-state information in their link-state databases.

True or False An OSPF area is a group of routers that share the same link-state information in their routing tables.

True. Changes to the topology, such as additions, deletions, or modifications of a link require the router to rerun the SPF algorithm and create a new SPF tree.

True or False Any time a router receives new information about the topology, the router must rerun the SPF algorithm, create a new SPF tree, and update the routing table.

False Area 0 is known as the backbone area.

True or False Area 1, used in a single-area OSPF, is also known as the backbone area.

True. The LSA includes a link ID field that identifies, by network number and mask, the object to which the link connects.

True or False Each router link is defined as an LSA type.

True.

True or False Generally, end users are not found within a backbone area.

True.

True or False Hierarchical networking defines area 0 as the core to which all other areas directly connect.

False In single-area OSPF, the LSDB covers the topology of the entire routing domain. Each router must maintain detailed information about every network in the routing domain.

True or False In Multiarea OSPF, the LSDB covers the topology of the entire routing domain.

False. Multiarea OSPF localizes the impact of a topology change within an area, stopping LSA flooding at the area boundry.

True or False In Multiarea OSPF, topology changes within an area still propagate across the area boundary.

False. In a multiarea network, an area can have one or more ABRs.

True or False In a multiarea network, an area can only have one ABR.

True.

True or False Multiarea OSPF is implemented in a two-layer area hierarchy.

False. Multiarea OSPF requires a hierarchical network design.

True or False Multiarea OSPF will support either a hierarchical or point-to-point network design.

True. Further, if the routes are not summarized, the routing table can become very large, depending on the size of the network.

True or False OSPF does not perform route summarization by default.

False. Redistribution in multiarea OSPF occurs when an ASBR connects different routing domains (e.g., EIGRP and OSPF) and configures them to exchange and advertise routing information between those routing domains.

True or False Redistribution in multiarea OSPF occurs when an ASR connects different routing domains and configures them to exchange and advertise routing information between those routing domains.

False. The SPF algorithm is CPU-intensive and the time it takes for calculation depends on the size of the area.

True or False Thankfully, the SPF algorithm is not very CPU-intensive, taking very little time to calculate topogly changes.

False. The RFCs for OSPF currently only specify up to 11 different LSA types.

True or False The RFCs for OSPF currently specify up to 15 different LSA types.

C) Wider routing update impact

Which of the following is NOT an advantage of the hierarchical-topology possibilities of multiarea OSPF? A) Reduced link-state update overhead B) Smaller routing tables C) Wider routing update impact D) Reduced frequency of SPF calculations

B) Multicast LSA

Which of the following is not a common OSPF LSA type? A) Network LSA B) Multicast LSA C) Router LSA D) Summary LSA

B) Type 2 The purpose of a type 2 LSA is to give other routers information about multiaccess networks within the same area.

____________________ LSA only exists for multiaccess and non-broadcast multiaccess (NBMA) networks where there is a DR elected and at least two routers on the multiaccess segment. A) Type 1 B) Type 2 C) Type 3 D) Type 4 E) Type 5

C) Type 3 ABRs collect type 1 LSAs in the LSDB. After an OSPF area has converged, the ABR creates a type 3 LSA for each of its learned OSPF networks. Therefore, an ABR with many OSPF routes must create type 3 LSAs for each network.

____________________ LSAs are used by ABRs to advertise networks from other areas. A) Type 1 B) Type 2 C) Type 3 D) Type 4 E) Type 5

E) Type 4 In addition, Type 4 LSAs are generated by ABRs and their link-state ID is identified by the router ID of the ASBR.

____________________ LSAs are used to advertise an ASBR to other areas and provide a route to the ASBR. A) Type 1 B) Type 2 C) Type 3 D) Type 4 E) Type 5

E) Type 5 Type 5 LSAs are also referred to as external LSA entries.

____________________ external LSAs describe routes to networks outside the OSPF routing domain, are originated by the ASBR, and are flooded to the entire routing domain. A) Type 1 B) Type 2 C) Type 3 D) Type 4 E) Type 5