OSPF Enterprise Exam

Refer to the exhibit. Which three statements describe the results of the OSPF election process of the topology that is shown in the exhibit?

-R3 will be elected BDR -R2 will be elected DR -r4 routre id is 172.16.1.1

An administrator is configuring single-area OSPF on a router. One of the networks that must be advertised is 64.102.0.0 255.255.255.128. What wildcard mask would the administrator use in the OSPF network statement?

0.0.0.127

Refer to the exhibit. If no router ID was manually configured, what would router Branch1 use as its OSPF router ID?

192.168.1.100 The first choice is the manually configured router ID with the router-id command. If the router ID is not manually configured, the router will choose the highest IPv4 address of the configured loopback interfaces. Finally if no loopback interfaces are configured, the router chooses the

Which task has to be performed on Router 1 for it to establish an OSPF adjacency with Router 2? Add the network 10.0.1.0 0.0.0.255 area 0 command to the OSPF process. Change the subnet mask of interface FastEthernet 0/0 to 255.255.255.0. Issue the clear ip ospf process command. Remove the passive interface command from interface FastEthernet 0/0.

Change the subnet mask of interface FastEthernet 0/0 to 255.255.255.0.

What is the recommended Cisco best practice for configuring an OSPF-enabled router so that each router can be easily identified when troubleshooting routing issues?

Configure a value using the router-id command

Refer to the exhibit. Suppose that routers B, C, and D have a default priority, and router A has a priority 0. Which conclusion can be drawn from the DR/BDR election process?​

If the DR fails, the new DR will be router B.

In an OSPFv2 configuration, what is the effect of entering the command network 192.168.1.1 0.0.0.0 area 0 ?

It tells the router which interface to turn on for the OSPF routing process.

Refer to the exhibit. On which router or routers would a default route be statically configured in a corporate environment that uses single area OSPF as the routing protocol?

R0-A

Refer to the exhibit. Which command did an administrator issue to produce this output?

R1# show ip ospf interface serial0/0/1

Refer to the exhibit. If the switch reboots and all routers have to re-establish OSPF adjacencies, which routers will become the new DR and BDR?

Router R4 will become the DR and router R1 will become the BDR. highest pritority from 1 -255 (0 = never a DR) highest router ID highest IP address of a loopback or active interface in the absence of a manually configured router ID. Loopback IP addresses take higher precedence than other interfaces

Refer to the exhibit. What is the OSPF cost to reach the router A LAN 172.16.1.0/24 from B

The formula used to calculate the OSPF cost is as follows: Cost = reference bandwidth / interface bandwidth The default reference bandwidth is 10^8 (100,000,000); therefore, the formula is Cost = 100,000,000 bps / interface bandwidth in bps Thus the cost to reach the A LAN 172.16.1.0/24 from B is as follows:Serial link (1544 Kbps) from B to A cost => 100,000,000 / 1,544,000 = 64Gigabit Ethernet link on A cost => 100,000,000 / 1,000,000,000 = 1Total cost to reach 172.16.1.0/24 = 64 + 1 = 65

Which OSPF data structure is identical on all OSPF routers that share the same area?

The link-state database lists information about all other routers within an area and is identical across all OSPF routers participating in that area.

Adjacency Database

This is where the details of the neighboring routers can be found.

What is a benefit of multiarea OSPF routing?

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

What is the format of the router ID on an OSPF-enabled router? a unique router host name that is configured on the router a unique phrase with no more than 16 characters a character string with no space an 8-bit number with a decimal value between 0 and 255 a 32-bit number formatted like an IPv4 address

a 32-bit number formatted like an IPv4 address

link-state update packet

advertise new information

single-area OSPF

all routers are in one area called the backbone area

What will an OSPF router prefer to use first as a router ID? the highest active interface IP that is configured on the router the highest active interface that participates in the routing process because of a specifically configured network statement a loopback interface that is configured with the highest IP address on the router any IP address that is configured using the router-id command

any IP address that is configured using the router-id command

database description packet

compare local topology to that sent by another router

Which type of OSPFv2 packet contains an abbreviated list of the LSDB of a sending router and is used by receiving routers to check against the local LSDB?

database description

hello packet

establish and maintain adjacencies

Which step does an OSPF-enabled router take immediately after establishing an adjacency with another router?

exchanges link-state advertisements

Which step in the link-state routing process is described by a router flooding link-state and cost information about each directly connected link?

exchanging link-state advertisements

After modifying the router ID on an OSPF router, what is the preferred method to make the new router ID effective? HQ# resume HQ# copy running-config startup-config HQ# clear ip ospf process HQ# clear ip route *

hq clear ip ospf process

Which three OSPF states are involved when two routers are forming an adjacency?

init down two-way

link-state request packet

query another router for additional information

What indicates to a link-state router that a neighbor is unreachable?

router no longer receives hello packets

An OSPF router has three directly connected networks; 172.16.0.0/16, 172.16.1.0/16, and 172.16.2.0/16. Which OSPF network command would advertise only the 172.16.1.0 network to neighbors?

router(config-router)# network 172.16.1.0 255.255.255.0 area 0

Which command will a network engineer issue to verify the configured hello and dead timer intervals on a point-to-point WAN link between two routers that are running OSPFv2?

show ip ospf interface serial 0/0/0

What command would be used to determine if a routing protocol-initiated relationship had been made with an adjacent router?

show ip ospf neighbor

Which command is used to verify that OSPF is enabled and also provides a list of the networks that are being advertised by the network?​

show ip protocols

A network technician issues the following commands when configuring a router:R1(config)# router ospf 11R1(config-router)# network 10.10.10.0 0.0.0.255 area 0What does the number 11 represent?

the OSPF process ID on R1

A network engineer has manually configured the hello interval to 15 seconds on an interface of a router that is running OSPFv2. By default, how will the dead interval on the interface be affected?

the dead interval will now be 60 seconds (dead interval = 4*hello

Refer to the exhibit. A network administrator has configured the OSPF timers to the values that are shown in the graphic. What is the result of having those manually configured timers?

the r1 dead timer expires between hello packets from r2

shortest path first

this is the algorithm used by OSPF

link-state database

this is where you can find the topology table

What is the reason for a network engineer to alter the default reference bandwidth parameter when configuring OSPF?

to more accurately reflect the cost of links greater than 100 Mb/s

What are the two purposes of an OSPF router ID?

to uniquely identify the router within the OSPF domain to facilitate router participation in the election of the designated router

In an OSPF network when are DR and BDR elections required?

when the routers are interconnected over a common ethernet network