OSPF-2

Question 1

What are the different neighbor states in OSPF?

Answer 1

1. Down: No Hello packet has been received from a previous “Full” Neighbor.
2. Attempt: Used for a manually configured neighbor.
3. Init: Hello packet received from a new neighbor.
4. 2-Way: Identifies compatible neighbors (non-DR/BDR relationships may stop here).
5. Exstart/Exchange: Master/Slave relationship determined and DBDS exchanged.
6. Loading: The LSR/LSA/LSU exchanges.
7. Full: Full State.

Question 2

Explain different OSPF LSA Types?

Answer 2

• (Type1)Router LSA : Describes router’s own links in an area.
• (Type2) Network LSA: Generated by DR (Designated Router) in multi-access networks.
• (Type3) Summary LSA: Advertises inter-area routes (sent by ABRs).
• (Type4) Summary ASBR LSA: Provides a route to an ASBR (Autonomous System Boundary Router).
• (Type5) External LSA: Used for external routes (redistributed into OSPF).
• (Type 7) NSSA LSA: Used in Not-So-Stubby Areas (NSSA) instead of Type 5.

Question 3

Explain different OSPF Network types.

Answer 3

1. Broadcast
2. Non-Broadcast (NBMA)
3. Point-to-Point
4. Point-to-multipoint
5. Point-to-multipoint non-broadcast

Question 4

What are the benefits of doing route summarization?

Answer 4

1. Smaller routing table.
2. Summarizes pool of addresses into one prefix.
3. Lessens the load on router processor and memory resources.
4. Less number of update messages.

Question 5

What is Route Redistribution?

Answer 5

Route redistribution is the process of taking routes learned via one routing protocol and injecting those routes into another routing protocol domain.