Enterprise Networks Exam 1 Study Guide
Matching
Adjacency - This is where the details of the neighboring router can be found Shortest Path First - This is the algorithm used by OSPF Single-Area OSPF - All the routers are in the back bone area. Link-State Database - This is where you can find the topology table
What will an OSPF router prefer to use first 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.
Open the packet tracer
Change the subnet mask of the interface.
Which type of OSPFv2 packet contains an abbreviated list of the LSBD of a sending router and is used by receiving routers to check against the local LSBD?
Database description
To establish a neighbor adjacency two OSPF routers will exchange hello packets. Which two values in the hello packets must match on both routers?
Dead interval and hello interval.
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
When an OSPF network is converged and no network topology changed has been detected by a router, how often will LSU packets be sent to neighboring routers?
Every 30 minutes.
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.
Which three statements describe features of the OSPF topology table?
It is a link-state database, When converged all routers in an area have identical topology tables, and the table can be viewed via the show ip ospf database command.
What indicates to a link-state router that a neighbor is unreachable?
It no longer receives hello packets
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 OSPF packet contains the different types of link-state advertisements?
LSU
Which type of address is 64.101.198.197
Public
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 serial 0/0/1
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?
R4 is DR, R1 is BDR
What does an OSPF area contain?
Routers that have the same link-state information in their LSBDs.
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 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 does the number 11 represent
The OSPF process ID on R1
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
What is used to facilitate hierarchical routing in OSPF?
The use of multiple areas.
What is a function of OSPF hello packets?
To discover neighbors and build adjacencies between them.
In an OSPF network when are DR and BDR elections required?
When the routers are interconnected over a common Ethernet network
What is the format of the router ID on an OSPF-enable router?
a 32-bit number formatted like an Ipv4 address.
Which three OSPF states are involved when two routers are forming an adjaceny?
Init, Two-way, Down
Which step in the link-state routing process is described by a router inserting best paths into the routing table?
Choosing the best route.
Which command is used to verify that OSPF is enabled and also provides a list of the networks that are being advertises by the network?
show ip protocols
By default, what is the OSPF cost for any link with a bandwidth of 100 Mb/s or greater?
1
What is the default router priority value for all Cisco OSPF Routers?
1
Refer to the exhibit. If no router ID was manually configured, what would router Branch 1 use as its OSPF Router ID?
192.168.1.100
Refer to the exhibit. What is the OSPF cost to reach the router A LAN 172.16.1.0/24 from B?
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.
After modifying the router ID on an OSPF router, what is the preferred method to make the new router ID effective?
HQ# clear IP OSPF process
Matching
Hello Packet - Establish and maintain adjacencies Link-state update packet - Advertise new information Database Description Packet - Compare local topology to that sent by another router Link-state request packet -Query another router for additional information
Refer to the exhibit. Supposed that routers B, C, and D have a default priority, and router A has a 0 priority. Which conclusion can be drawn from the DR/BDR election process.
If the DR fails, the new DR will be router B
Refer to the exhibit. A network administrator has configured OSPFv2 on the two cisco routers but PC1 is unable to connect to PC2. What is the most likely problem?
Interface Fa0/0 has not been activated for OSPFv2 on R2
Which OSPF data structure is identical on all OSPF routers that share the same area?
Link-State Database
A network Engineer has manually configured the hello interval to 15 seconds on an interface of 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 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 and to facilitate router participation in the election of the designated router.
What is the benefit of multi area OSPF routing?
Topology changes in one area do not cause SPF recalculations in other areas.
