Cisco CCNA S3 Module 1-2
An administrator is configuring single-area OSPF on a router. One of the networks that must be advertised is 128.107.0.0 255.255.255.192. What wildcard mask would the administrator use in the OSPF network statement?
0.0.0.63
By default, what is the OSPF cost for any link with a bandwidth of 100 Mb/s or greater?
1
What is the default priority value for all Cisco OSPF routers?
1
What is the OSPF cost to reach the router A LAN 172.16.1.0/24 from B through a 1544 Kbps serial interface and a Gigabit ethernet interface?
65
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.
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
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.
Which three OSPF states are involved when two routers are forming an adjacency?
Link, Down, Two-Way
An OSPF router has three directly connected networks; 172.16.0.0/16, 172.16.1.0/16, and 172.16.20/16. 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
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.
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 32-bit number formatted like an IPv4 address
What will an OSPF router prefer to use first as a router ID?
any ip address that is configured using the router-id command
Which step in the link-state routing process is described by a router building a link-state database based on received LSAs?
building the topology table
After modifying the router ID on an OSPF router, what is the preferred method to make the new router ID effective?
clear ip ospf process
Which step in the link-state routing process is described by a router sending Hello packets out all of the OSPF-enabled interfaces?
establishing neighbor 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
Which step in the link-state routing process is described by a router running an algorithm to determine the best path to each destination?
executing the SPF algorithm
To establish a neighbor adjacency two OSPF routers will exchange hello packets. Which two values in the hello packets must match on both routers?
hello intervals, dead intervals
What indicates to a link-state router that a neighbor is unreachable?
if the router no longer receives hello packets
Which OSPF data structure is identical on all OSPF routers that share the same area?
link-state database
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 11 R1(config-router)#network 10.10.10.0 0.0.0.255 area 0. What does the number 11 represent?
the OSPF process ID on R1
What is used to facilitate hierarchical routing in OSPF?
the use of multiple areas
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
