Lesson 6

A(n) ________ is a routing protocol that was designed and intended for use inside a single autonomous system.

An Interior Gateway Protocol (IGP) is a routing protocol that was designed and intended for use inside a single autonomous system.

An engineer would like to remove the network commands in OSFP configuration mode. What Cisco IOS command does this engineer need to use?

An engineer would use the no network network-id area area-id subcommands in OSPF configuration mode to remove the network commands.Remediation Link: Chapter 20, OSPF Interface Configuration

Which term does OSPF use to describe the special OSPF area to which all other areas must connect?

Backbone area is the term used to describe the special OSPF area to which all other areas must connect.

Which components are used as part of EIGRP's default metric?

By default, EIGRP uses a composite metric based on the minimum path bandwidth and the cumulative delays.D) By default, EIGRP uses a composite metric based on the minimum path bandwidth and the cumulative delays.

Which Cisco IOS command is used to alter the maximum number of equal-cost OSPF routes that are inserted into the routing table?

By default, four different equal cost OSPF routes will be inserted into the routing table. To change this default, use the maximum-paths command.

By default, what is the maximum number of equal-cost OSPF routes that will be inserted into the routing table?

By default, four different equal-cost OSPF routes will be inserted into the routing table. To change this default, use the maximum-paths command.

Which of the following is a routing protocol designed and intended for use between different autonomous systems?

EGP is a routing protocol designed and intended for use between different autonomous systems.

Each OSPF router that originates an LSA is responsible for reflooding it every ________.

Every OSPF device that originates an LSA is responsible for its maintenance, which requires it to be reflooded every 30 minutes even if the network is stable.

An engineer would like to set the cost of an OSPF interface directly on her router. Which interface subcommand allows the engineer to set the cost directly?

In order to set the cost of an OSPF interface directly, use the interface subcommand ip ospf costx.

What default reference bandwidth does OSPF use when calculating the metric?

Keep in mind that the default reference bandwidth currently used by OSPF on a Cisco device is 100 Mbps. This means that a 100 Mbps, 1 Gbps, and 10 Gbps interface all look the same in the eyes of OSPF when calculating the metric (because OSPF rounds to the nearest whole number).

What term does OSPF use to reference a router that has interfaces in more than one area?

OSPF uses the term Area Border Router (ABR) to reference a router that has interfaces in more than one area.

Which IP multicast address is used by OSPF to communicate with all OSPF speaking routers?

OSPF uses two different IPv4 multicast addresses: 224.0.0.5 and 224.0.0.6. The 224.0.0.5 address is used to speak to all OSPF speaking routers; the 224.0.0.6 address is used for communications between DR/BDR OSPF routers when needed.Remediation Link: Chapter 19, Meeting Neighbors and Learning Their Router ID

Which IGP routing protocol has traditionally been Cisco proprietary?

Of the major IGPs that have been traditionally implemented in the last several years, the only one that is Cisco proprietary is EIGRP; however, Cisco published EIGRP as an RFC around 2013, making it open for other vendors to implement.

Which routing protocols are not considered Distance Vector?

RIP, IGRP, and EIGRP are all considered distance vector protocols (or advanced distance vector), while OSPF is a link state protocol.

What is the administrative distance of OSPF routes?

The administrative distance of OSPF is 110, EIGRP is 90, RIP is 120, and IS-IS is 115.

When viewing the Cisco IOS routing table with the show ip route command, what code is used to denote OSPF routes that are not within the local area?

The code IA (Interarea) is added to all those OSPF routes that are sourced by an area that is not local.

Which single OSPF network statement will correctly include all the interfaces on a device whose IP addresses only begin with a 10.10.8, 10.10.9, 10.10.10, or 10.10.11?

The concept of a wildcard mask often confuses those new to Cisco networking and should be practiced until it is clear how it works. For this example, 10.10.8.0 0.0.3.255 will include all interfaces on a device with IP addresses that begin with 10.10.8, 10.10.9, 10.10.10, and 10.10.11. The 0.0.3.255 address works out to a subnet mask of 255.255.252.0, so the subnet 10.10.8.0 255.255.252.0 would include these same address ranges. All you have to do is invert the subnet mask: 255.255.252.0 = 11111111 11111111 11111100 00000000 inverted = 00000000 00000000 000000111111111 = 0.0.3.255.

Which OSPF network statement will correctly include all the interfaces on a device that begin with an IP address of 172.16.0.0/16?

The concept of a wildcard mask often confuses those new to Cisco networking and should be practiced until it is clear how it works. For this example, 172.16.0.0 0.0.255.255 will include all interfaces on a device that begin with an IP address of 172.16.x.x.Remediation Link: Chapter 20, Wildcard Matching with the network Command

What default length is used for the OSPF dead interval?

The default OSPF Dead Interval is configured as four times the current Hello timer unless the Dead Interval is independently configured.Remediation Link: Chapter 19, Maintaining Neighbors and the LSDB

What is the default administrative distance IGRP routes?

The default administrative distance of IGRP is 100.

What type of OSPF packet is used to list the LSAs that are known by a device?

The exchange of known LSAs between two OSPF devices (if not neighbors yet) or neighbors is done with an OSPF Database Description (DD) packet.

Which Cisco IOS command is used to enable OSPF on an interface using interface configuration mode commands?

The ip ospf process-id area area command can be used in interface configuration mode to insert a specific interface into the OSPF process. This is used as an alternative to the network command in OSPF router configuration mode.

An engineer needs to ensure that a specific OSPF interface is not set to passive. Which Cisco IOS command could this engineer use to change the configuration for the interface?

The no passive-interfacetype number command can be used for any interfaces that do not need to be passive.

Which Cisco IOS command is used to list information about the OSPF LSDB on a device?

The show ip ospf database command is used to display the contents of the OSPF Link State Database (LSDB).

Which Cisco IOS command can be used to display whether an interface is configured as passive?

The show ip ospf interface command can be used to display whether an interface is configured as passive. The show ip ospf interface brief command does not display this information.

Which Cisco IOS command is used to display the current OSPF neighbors and their RIDs?

The show ip ospf neighbor Cisco IOS command is used to display the current OSPF (v2-IPv4) neighbors of the local device.

Which Cisco IOS command lists a group of messages for each IPv4 routing protocol running on a router?

The show ip protocols command is used to list a group of messages for each IPv4 routing protocol running on a router.

An engineer used the Cisco IOS show ip ospf neighbor command and received the following output:Neighbor ID Pri State Dead Time Address Interface3.3.3.3 1 FULL/DR 00:00:37 10.1.13.3 GigabitEthernet0/1/04.4.4.4 1 FULL/BDR 00:00:34 10.1.14.4 GigabitEthernet0/2/0What does the state field tell us about the router with the Neighbor ID 4.4.4.4?

The state FULL/BDR shows that the neighbor state is full, and the neighbor is the backup designated router (BDR).

Which Cisco IOS commands can be used to display the interfaces that have been enabled into the local OSPF process?

Two commands can display the interfaces that have been enabled into the local OSPF process, and one is a slave to the other: show ip ospf interface will show a detailed display of the interfaces that have been enabled and a number of configuration details about each. When the brief keyword is added, the command will still display those interfaces that have been enabled but in a shorter condensed format.D) Two commands can display the interfaces that have been enabled into the local OSPF process, and one is a slave to the other: show ip ospf interface will show a detailed display of the interfaces that have been enabled and a number of configuration details about each. When the brief keyword is added, the command will still display those interfaces that have been enabled but in a shorter condensed format.

When a pair of OSPF neighbors has reached the ________ state, they can exchange their LSDB with each other.

When a device initially sees a neighbor, the OSPF state will transition to Init; when it sees its own RID in an updated LSDB packet, the OSPF state will transition to 2-way.

In which OSPF state would a neighbor be if it has learned of a neighbor's existence but has not yet seen its own RID in an LSDB update?

When a device initially sees a neighbor, the OSPF state will transition to Init; when it sees its own RID in an updated OSPF (hello) packet, the OSPF state will transition to 2-way.

What type of OSPF packet is used to actually send LSAs between neighbors?

When a pair of OSPF neighbors has exchanged a list of their known LSAs with the OSPF DD (Database Description) packets, the actual LSAs that are not known by each respective device are sent using Link State Update (LSU) packets.

Which Cisco IOS command is used to configure the OSPF reference bandwidth setting?

When altering the OSPF reference bandwidth, use the Cisco IOS auto-cost reference-bandwidth speed command.

Which Cisco IOS command is used to advertise a default route into OSPF regardless of whether a default static route is configured?

When configured in OSPF router configuration mode, the default-information originate command will advertise a default route into OSPF as long as a static default route exists in the routing table; to eliminate this check, the always parameter can be added to this command.

Which Cisco IOS command is used to alter the default behavior and configure all interfaces as passive?

When entered in router configuration mode, the passive-interface default command is used to alter the default behavior and configure all interfaces as passive. In this type of configuration, interfaces that are intended to form neighborships must be manually enabled.