Flashcards in this deck (19)

• What type of protocol is OSPF?

  Link-state IGP, protocol number 89, uses Dijkstra SPF algorithm for shortest path calculation.
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• What are the five types of OSPFv2 packets?

  1. Hello (Type 1)
  2. Database Description (Type 2)
  3. Link State Request (Type 3)
  4. Link State Update (Type 4)
  5. Link State Acknowledgement (Type 5)
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• What is the purpose of Hello packets in OSPF?

  Maintain neighbor relationships and facilitate DR/BDR election.
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• What is an Internal router in OSPF?

  A router with all interfaces in one area.
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• What is the role of an Area Border Router (ABR)?

  Connects multiple areas, including Area 0.
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• What is an Autonomous System Boundary Router (ASBR)?

  Redistributes routes into OSPF from other protocols.
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• What is required for full OSPF functionality?

  Backbone Area 0.
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• How does hierarchical design benefit OSPF?

  Reduces LSA flooding and improves scalability.
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• What does DR stand for in OSPF?

  Designated Router.
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• What does BDR stand for in OSPF?

  Backup Designated Router.
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• How is the DR/BDR elected?

  Via OSPF Hello packets based on priority; highest wins, tie-breaker is router ID.
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• What is the Router ID (RID) in OSPF?

  A 32-bit value that uniquely identifies a router.
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• How is the Router ID (RID) auto-selected?

  Highest loopback IPv4 address or highest active interface if no loopback.
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• What is the purpose of the Link State Database (LSDB)?

  Contains all LSAs and is identical across all routers in an area.
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• What does the SPF algorithm do?

  Computes least-cost paths from the router to all destinations.
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• How do you configure single-area OSPF in Junos?

  Under [edit protocols ospf], define area and attach interfaces.
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• What command is used to set the router ID explicitly in OSPF?

  set routing-options router-id x.x.x.x.
  networking junos
• What should you specify if there are issues with adjacencies in OSPF?

  Specify interface address instead of name.
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• What are critical exam concepts for OSPF?

  Know LSA types, metric calculation, DR/BDR election scenarios, LSDB synchronization, and troubleshooting adjacencies.
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