Question 1       What is OSPF?

Question 2       What Is Backbone Area?

Question 3       Why and on what environment do we implement OSPF?

Question 4       Why are loopbacks advertised as /32 host routes in OSPF?

Question 5       Mention some characteristics of OSPF?

Question 6       What is OSPF’s metric? How is it identified in routing table? Does it support redistribution?

Question 7       Explain LSA and its all Types such as LSA 1, 2, 3,4,5,7. When do we use LSA type 6?

Question 8       What is the concept of “auto cost reference-bandwidth” and in what scenarios we should use it?

Question 9       Why it’s known as Link state protocol? How it’s different than EIGRP? What algorithm does it use?

Question 10     Explain Area Border Router?

Question 11     What will happen if we make priority of an OSPF router as “zero”?

Question 12     How do I change the reference bandwidth in OSPF?

Question 13     How does OSPF calculate its’ metric or cost?

Question 14     How Do We Configure OSPF Routing Protocol?

Question 15     What are Different OSPF LSA Types?

Question 16     What are the states used in OSPF when forming neighborship?

Question 17     What Is Autonomous System Border Router?

Question 18     What are different neighbor states in OSPF?

Question 19     Which type of area blocks external route?

Question 20     What algorithm is used by OSPF if equal cost routes exist?

Question 21     What are the multicast IPs used by OSPF? What multicast IP does DR/BDR router and non-DR use?

Question 22     What are the packet types does OSPF use? Explain Hello, Dead Timers, LSA, LSU, LSR packets.

Question 23     What is role of topology and routing table in OSPF?

Question 24     What Is OSPF Router-Id?

Question 25     Does DR/BDR election happen in OSPF Point to Point Network?

Question 26     What are the tables Maintained By OSPF?

Question 27     What is the link-state retransmit interval, and what is the command to set it?

Question 28     What different activities neighbour router perform in OSPF?

Question 29     What is the purpose of the variable IP-OSPF-Transmit-Delay?

Question 30     Is it true that only the static option of the virtual link in OSPF allows discontiguous networks, regardless of the mask propagation properties?

Question 31     On which algorithms OSPF depends? What is the principle behind it?

Question 32     Are the multicast IP addresses mapped to MAC-level multicast addresses?

Question 33     Does the Cisco OSPF implementation support IP TOS-based routing?

Question 34     What is the concept of Virtual-link in OSPF? Can virtual link be formed thru stub area?

Question 35     Does the offset-list subcommand work for OSPF?

Question 36     Can an OSPF default be originated into the system based on external information on a router that does not itself have a default?

Question 37     Briefly explain functioning and working of different OSPF?

Question 38     Can I use the distribute-list in/out command with OSPF to filter routes?

Question 39     How can I give preference to OSPF interarea routes over intra-area routes?

Question 40     What Is The Default Dead Interval?

Question 41     What LSA is used for inter area communication? What LSA type is used for inter protocol communication in OSPF?

Question 42     What are the different OSPF network types and give an example for each?

Question 43     Do I need to manually set up adjacencies for routers on the Switched Multimegabit Data Service (SMDS) cloud with the OSPF neighbor subcommand?

Question 44     Explain the concept of Area Border Router (ABR) and Autonomous System Border Router (ASBR). Can router sitting between area 2 and 3 be called as ABR?

Question 45     How OSPF inter area, external routes are denoted or represented in routing table?

Question 46     When routes are redistributed between OSPF processes, are all shortest path first algorithm (SPF) metrics preserved, or is the default metric value used?

Question 47     Name tables which OSPF maintain?

Question 48     What is the DR/BDR in OSPF? How these are elected and in what scenario?

Question 49     How does Cisco accommodate OSPF routing on partial-mesh Frame Relay networks?

Question 50     Which address-wild-mask pair should I use for assigning an unnumbered interface to an area?

Question 51     What Is The Need For Dividing The Autonomous System Into Various Areas?

Question 52     Can I have one numbered side and leave the other side unnumbered in OSPF?

Question 53     Why do I receive the “cannot allocate router id” error message when I configure Router OSPF One?

Question 54     What Is The Benefit Of Dividing The Entire Network Into Areas?

Question 55     Why do I receive the “unknown routing protocol” error message when I configure Router OSPF One?

Question 56     What Is The Default Hello Interval?

Question 57     What do the states DR, BDR, and DROTHER mean in show ip OSPF interface command output?

Question 58     When I issue the show ip OSPF neighbor command, why do I only see FULL/DR and FULL/BDR, with all other neighbors showing 2-WAY/DROTHER?

Question 59     Why do I not see OSPF neighbors as FULL/DR or FULL/BDR on my serial link?

Question 60     Do I need any special commands to run OSPF over BRI/PRI links?

Question 61     Explain OSPF Timers?

Question 62     Do I need any special commands to run OSPF over asynchronous links?

Question 63     Which Cisco IOS Software release began support for per-interface authentication type in OSPF?

Question 64     Can I control the P-bit when importing external routes into a not-so-stubby area (NSSA)?

Question 65     Why are OSPF show commands responding so slowly?

Question 66     What does the clear ip OSPF redistribution command do?

Question 67     Does OSPF form adjacencies with neighbors that are not on the same subnet?

Question 68     What Are The Steps Required To Change Neighborship Into Adjacency?

Question 69     How often does OSPF send out link-state advertisements (LSAs)?

Question 70     How do I stop individual interfaces from developing adjacencies in an OSPF network?

Question 71     When I have two type 5 link-state advertisements (LSAs) for the same external network in the OSPF database, which path should be installed in the IP routing table?

Question 72     Explain OSPF LSA, LSU And LSR?

Question 73     What problems can cause OSPF neighborship in “down” state?

Question 74     Where does the summarization happen in OSPF? Which command is used for summarization at ABR and at ASBR?

Question 75     Should I use the same process number while configuring OSPF on multiple routers within the same network?

Question 76     I have a router that runs Cisco Express Forwarding (CEF) and OSPF, who does load-balancing when there are multiple links to a destination?

Question 77     What is “Process-id”? Does it have local or global significance? Does it need to be same on OSPF neighbor routers?

Question 78     How does OSPF use two Multilink paths to transfer packets?

Question 79     How can you detect the topological changes rapidly?

Question 80     Explain The Various OSPF States?

Question 81     Can we have OSPF run over a GRE tunnel?

Question 82     Is there a way to manipulate and prefer the Type 3 LSAs to originate from two different areas sent to the non-backbone area?

Question 83     Is there a drop/flap of an OSPF neighborship when changing an OSPF area type from NSSA no-summary to NSSA?

Question 84     Why DR And BDR Are Elected In OSPF?

Question 85     What is the concept of “Area” in OSPF? What is Backbone area, stub area, Totally Stubby Area, Not So Stubby area (NSSA)?

Question 86     In the %OSPF-5-ADJCHG: Process ID, Nbr [ip-address] on Port-channel31 from FULL to EXSTART, SeqNumberMismatch error message, what does SeqNumberMismatch signify?

Question 87     How does ISPF impact or improve the OSPF network?

Question 88     Is there a way to compare Cisco NX-OS/IOS OSPF commands?

Question 89     Is there any feature of OSPF protocol for quick convergence and a slow re-convergence of routes?

Question 90     What does BADSEQNUM in the %OSPF-5-NBRSTATE: OSPF-101 [5330] Process 101, Nbr on Vlan7 02 from FULL to EXSTART, BADSEQNUM OSPF log message mean?

Question 91     What will be Hello/Dead timers in network having link capacity of >T1 and <=T1?

Question 92     What Parameters Must Match For Two Routers To Become Neighbors?

Question 93     What is O E1, O E2 letters in OSPF? Which is default external type 1 or external type 2?