ospf
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What is Ospf ? features & Ospf states
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OPSF: -Open Shortest Path First (OSPF) is a widely used interior gateway protocol for IP networks. -It is a link state routing protocol that calculates the shortest path to a destination using the Dijkstra algorithm. -Open Standard. – AD value 110 Key features of OSPF include: Hierarchical design: OSPF […]
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OSPF Router Types
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OSPF (Open Shortest Path First) routers are classified into four types: Backbone Area Router: This is a router which resides in backbone area. The backbone area is set to area 0. Backbone Area Router Internal Router: A router that has all its interfaces connected to a within same OSPF area […]
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OSPF DR/BDR Election
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How DR/BDR gets elected in OSPF: The purpose of having a DR and BDR is to reduce the amount of network traffic generated by OSPF, as only the DR and BDR exchange full routing information, while other routers only exchange minimal information. This helps ensure the stability and efficiency […]
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Why Ospf Neighbors Stuck In Init State or 2-way or Exchange
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Why Are Ospf Neighbors Stuck In Init State— 1- INIT State OSPF can be stuck in INIT due to the mismatch in hello packet parameters such as . –>> Hello/dead intervals. –>> Authentication. –>> Stubflag. –>> Interface subnet mask. –>> Area ID . MTU will come into the picture when […]
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Network engineer Interview Question
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Networking Interview Question for routing protocol OSPF Q. How many types of area exist in OSPF and types of LSA are allowed ? Q. Different OSPF packet types ? Q. If you see how as DRother under show ip ospf neigbor . Whats wrong with the output ? Q. […]
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ospf scenario
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ospf scenario Highest IP address ABR routes convert the type7 into type 5. Default route is not generated by default in area nssa unless “are nssa <> default originate ” configured. Totally stubby NSSA area generate the default route by default. DR/BDR does not support the preempt therefore if DR […]
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ospf scenario based questions
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ospf scenario based questions Scenario 1 – OSPF full neigborship is not coming up between routers — 1. Hello and Dead timer or Area ID, Authentication password/type/key or Area type are mismatch between router.2. Trying to build OSPF neigborship on secondary address.4. OSPF not enabled on correct interface […]
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ospf configuration troubleshooting
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There are some command to help troubleshoot of OSPF and configuration. 1- show ip protocols (this command confirm on router , how many protocol is running include OSPF) 2 – show ip route ( dynamic routes are learned by OSPF) 3- show ip ospf (display OSPF info for all OSPF processes) 4- show ip […]
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OSPF Troubleshooting (Stuck in 2 way state or Exchange state)
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OSPF Troubleshooting (Stuck in 2 way state or Exchange state) There is a difference between OSPF in 2-Way state and OSPF ‘stuck’ in 2-Way state. In a broadcast network, 2 routers who are neither DR or BDR, will form a 2-Way neighborship with each other and ‘FULL’ with the DR/BDRs […]