CNA 251 | Ch. 9, Multiarea OSPF

O IA

A network administrator is verifying a multi-area OSPF configuration by checking the routing table on a router in area 1. The administrator notices a route to a network that is connected to a router in area 2. Which code appears in front of this route in the routing table within area 1?

Internal router

A router that has all of its interfaces in the same area.

Autonomous System Boundary Router (ASBR)

A router that has at least one interface attached to an external internetwork.

Area Border Router (ABR)

A router that has interfaces attached to multiple areas

Backbone router

A router that resides in Area 0.

Regular (Non-backbone) area

An OSPF area that connects users and resources.

Backbone (Transit) area

An OSPF area whose primary function is the fast and efficient movement of IP packets.

Router LSA

LSA Type 1

Network LSA

LSA Type 2

Summary LSAs

LSA Type 3 and 4

AS External LSA

LSA Type 5

Multicast OSPF LSA

LSA Type 6

Defined for NSSAs

LSA Type 7

External Attributes LSA for Border Gateway Protocol (BGP)

LSA Type 8

Opaque LSAs

LSA Type 9, 10, and 11

Type 4

LSA that advertises an ASBR to other areas and provides a route to it.

Type 5

LSA that advertises external (non-OSPF) network addresses.

Type 3

LSA that advertises networks from other areas by ABRs

Type 1

LSA that contains a list of directly connected interfaces, link types, neighbors, and link states and is flooded only within the area in which it originated.

Type 2

LSA that identifies the routers and network address of the multicast link.

Type 1

LSA that includes a list of directly attached network prefixes and link type

Type 2

LSA that only exists for multiaccess and non-broadcast networks where there is a DR elected and at least two routers on the multiaccess segment.

Redistribution

Occurrence that happens when an ASBR connects different routing domains and configures them to exchange and advertise routing information between those routing domains.

IA

Routing table designation for a summay LSA

E1 and E2 *Note: E2 is the default

Routing table designation for an external LSA. (two answers)

O

Routing table designation for an intra-area route.

Type 4/Summary LSA Type 5/AS External LSA

These two LSA types are used collectively to identify an ASBR and advertise external networks into an OSPF routing domain.

Type 4

This LSA type identifies the ASBR and provides a route to it.

Type 5

This LSA type is used to describe routes to networks outside of the OSPF routing domain.

Area 0

This area, used in single-area OSPF, is known as the backbone area.

link-state database (LSDB)

Too many routers in one area increase the load on the CPU and create a large ____.

Interarea traffic

Traffic that moves from one area to another area.

True. stub area, totally stubby area, and not-so-stubby area are beyond the scope of Cisco III.

True or False? A regular OSPF area has four different subtypes, including standard, stub, totally stubby, and not-so-stubby area.

False. A type 3 LSA is

True or False? A type 5 LSA is required for every subnet.

False. They will be identical

True or False? All internal routers in an area have altering LSDBs.

True

True or False? Routing information destined for another area can get there only via the Area Border Router (ABR) of the local area.

True

True or False? The purpose of a type 2 LSA is to give other routers information about multiaccess networks within the same area.

Type 3

Type of LSA used by ABRs to advertise networks from other areas.

Type 2

What OSPF LSA type is used to inform routers of the router ID of the DR in each multiaccess network in an OSPF area?

A. To reduce SPF calculations B. To reduce use of memory and processor resources

What are two reasons for creating an OSPF network with multiple areas? (Choose two.) A. To reduce SPF calculations B. To reduce use of memory and processor resources C. To simplify configuration D. To provide areas in the network for routers that are not running OSPF E. To ensure that an area is used to connect the network to the Internet

Backbone router and ABR

What classification would a router connecting to Area 0 and Area 1 be given?

B. The route to reach an ASBR

What information is advertised in a type 4 LSA? A. The router ID of the DR B. The route to reach an ASBR C. Networks reachable outside the OSPF domain D. Networks reachable outside the local area

A. Topology changes in one area do not cause SPF recalculations in other areas.

What is a benefit of multiarea OSPF routing? A. Topology changes in one area do not cause SPF recalculations in other areas. B. Automatic route summarization occurs by default between areas. C. Routers in all areas share the same link-state database and have a complete picture of the entire network. D. A backbone area is not required.

3

What is the maximum number of areas that a router should be in?

60

What is the maximum number of neighbors that a single router should have?

50

What is the maximum number of routers that an area should have?

B. The use of multiple areas

What is used to facilitate hierarchical routing in OSPF? A. The election of designated routers B. The use of multiple areas C. Autosummarization D. Frequent SPF calculations

D. O IA

What routing table descriptor is used to identify OSPF summary networks that originate from an ABR? A. O B. O E1 C. O E2 D. O IA

Type 5

What type of OSPF LSA is originated by ASBR routers to advertise external routes?

Type 1

Which LSA type advertises directly connected OSPF-enabled links to other OSPF routers within the OSPF area they originated?

Type 2

Which LSA type is flooded by a designated router to other OSPF routers within the same area?

D. They are required to perform any summarization or redistribution tasks.

Which characteristic describes both ABRs and ASBRs that are implemented in a multiarea OSPF network? A.They are required to reload frequently and quickly in order to update the LSDB. B. They both run multiple routing protocols simultaneously. C. They usually have many local networks attached. D. They are required to perform any summarization or redistribution tasks.

A. Define the OSPF parameters. D. Define the network requirements. E. Gather the required parameters.

Which three steps in the design and implementation of a multiarea OSPF network are considered planning steps? (Choose three.) A. Define the OSPF parameters. B. Troubleshoot the configurations. C. Verify OSPF. D. Define the network requirements. E. Gather the required parameters. F. Configure OSPF.

A. Type 3 LSAs are generated without requiring a full SPF calculation.​ B. Type 3 LSAs are used to update routes between OSPF areas.

Which two statements correctly describe OSPF type 3 LSAs? (Choose two.) A. Type 3 LSAs are generated without requiring a full SPF calculation.​ B. Type 3 LSAs are used to update routes between OSPF areas. C. Type 3 LSAs are known as autonomous system external LSA entries.​ D. Type 3 LSAs are used for routes to networks outside the OSPF autonomous system​. E. Type 3 LSAs are known as router link entries​.

C. OSPF routers within an area have the same link-state information. D. OSPF routers may have large routing tables if routes are not summarized.

Which two statements describe OSPF? (Choose two.) A. OSPF performs automatic route summarization by default. B. OSPF must be implemented in a three-layer area hierarchy. C. OSPF routers within an area have the same link-state information. D. OSPF routers may have large routing tables if routes are not summarized. E. OSPF uses the SPF algorithm, which requires few CPU cycles.

Type 1 & Type 2

Which two types of LSAs are flooded only within the area in which they originated? (Choose two.)

Area Border Router (ABR)

Which type of OSPF router will generate type 3 LSAs?