Ccna Tesking

Question 1 Which of the following statements below best describe the process identifier that is used to run OSPF on a router? (Choose two) A – It is an optional parameter required only if multiple OSPF processes are running on the router B – It is locally significant C – It is needed to identify a unique instance of an OSPF database D – All routers in the same OSPF area must have the same processID if they are to exchange routing information

Answer: B C Question 2: Why R1 can’t establish an OSPF neighbor relationship with R3 according to the following graphic? (Choose two)

A – Configure EIGRP on these routers with a lower administrative distance B – All routers should be configured for backbone Area 1 C – R1 and R3 have been configured in different areas D – The hello and deadinterval timers are not configured the same values on R1 and R3

Answer: C D Explanation: A is not correct because configure EIGRP on these routers (with a lower administrative distance) will force these routers to run EIGRP, not OSPF. B is not correct because the backbone area of OSPF is always Area 0. C and D are correct because these entries must match on neighboring routers:

- Hello and deadintervals – Area ID (Area 0 in this case) – Authentication password – Stub area flag Question 3: Which items are correct about the routing protocol OSPF? (Choose three) A – Support VLSM B – Increase routing overhead on the network C – Confine network instability to one area of the network D – Allow extensive control of routing updates

Answer: A C D Explanation: Routing overhead is the amountof information needed to describe the changes in a dynamic network topology. All routers in an OSPF area have identical copies of the topology database and the topology database of one area is hidden from the rest of the areas to reduce routing overhead because fewer routing updates are sent and smaller routing trees are computed and maintained (allow extensive control of routing updates andconfine network instability to one area of the network). Question 4: Which three features are of OSPF routing protocol? (Choose three) A – Converge quickly B – OSPF is a classful routing protocol C – Identify the best route by use of cost D – Before exchanging routing information, OSPF routers find out neighbors

Answer: A C D Question 5: OSPF routing uses the concept of areas. What are thecharacteristics of OSPF areas? (Chose three) A – Each OSPF area requires a loopback interface to be configured B – Areas may be assigned any number from 0 to 65535 C – Area 0 is called the backbone area D – Hierarchical OSPF networks do not require multiple areas

E – Multiple OSPF areas must connect to area 0 F – Single area OSPF networks must be configured in area 1

Answer: B C E Explanation: I usedto think the answers should be C D E and here is my explanation: OSPF can use an active interface for its router ID, so a loopback interface is not a must > A is incorrect. OSPF Area is a 32-bit number so we can use up to 232 – 1 = 4294967296 – 1 (since Area 0 is the first area). Remember that only process ID is a 16-bit number and ranges from 1 to 65535 -> B is incorrect. F is incorrect toobecause single area OSPF netwoks must be configured in Area 0, which is called the backbone area. For answer D, it is a bit hard to guess what they want to say about “hierarchical” but we should understand “Hierarchical OSPF networks” as “OSPF networks”. D is correct bercause we can only have one area (area 0 – the backbone area) for our networks. But TT commented on 01-11-2010: Especially to note onchoice B, D, and E: Choice B: we all know that The areas can be any number from 0 to 4.2 billion and 1 to 65,535 for the Process ID. As choice B specifies ‘area’ (be aware, it’s not saying ‘process id), there is no reason to say that we cannot assign numbers from 0 to 65535 for area # (it is using ‘may be’, not ‘have to be’ or ‘ought to be’). Hence, we do not worry about assigning ’0′. Choice E:...