1
Q
What are the different neighbor states in OSPF?
A
- Down: No Hello packet has been received from a previous “Full” Neighbor.
- Attempt: Used for a manually configured neighbor.
- Init: Hello packet received from a new neighbor.
- 2-Way: Identifies compatible neighbors (non-DR/BDR relationships may stop here).
- Exstart/Exchange: Master/Slave relationship determined and DBDS exchanged.
- Loading: The LSR/LSA/LSU exchanges.
- Full: Full State.
2
Q
Explain different OSPF LSA Types?
A
- (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.
3
Q
Explain different OSPF Network types.
A
- Broadcast
- Non-Broadcast (NBMA)
- Point-to-Point
- Point-to-multipoint
- Point-to-multipoint non-broadcast
4
Q
What are the benefits of doing route summarization?
A
- Smaller routing table.
- Summarizes pool of addresses into one prefix.
- Lessens the load on router processor and memory resources.
- Less number of update messages.
5
Q
What is Route Redistribution?
A
Route redistribution is the process of taking routes learned via one routing protocol and injecting those routes into another routing protocol domain.
