OSPF Introduction Part 1

Question 1

What is the OSPF RFC?

Answer 1

RFC 2328

Question 2

Is OSPF a static or a dynamic routing protocol?

Answer 2

Dynamic routing protocol

Question 3

Is OSPF a link-state or distance vector routing protocol?

Answer 3

OSPF is a Link-state routing protocol

Question 4

which version for ipv4 OSPF and ipv6 ospf?

Answer 4

ospf v2 and ospf v3

Question 5

Why use OSPF?

Answer 5

1. used within an organization
2. it is a Interior Gateway Routing Protocol (IGP)
3. OSPF is classless (to overcome disadv. of RIP)
4. OSPF is a open standard hence can be used in multiple vendors
5. Highly scalable and configurable
6. Speed of convergence
7. OSPF is secure

Question 6

What are the different OSPF databases and tables?

Answer 6

1. Adjacency Database
2. 1. Neighbor Table
3. Link state database (LSDB)
4. 1 topology table
5. Forwarding Database
6. 1 Routing table (show ip route)

Question 7

What are the OSPF Packet types?

Answer 7

Type 1 : Hello Packets
Type 2 : Database descriptor packet (DBD)
Type3 : Link state request (LSR)
Type 4: Link state update (LSU)
Type 5 : Link state Acknowledgement (LSA)

Question 8

what is a DBD packet? Type 2 OSPF packet

Answer 8

After OSPF is established, DBD packets are used to compare the link-state database of the OSPF neighbors to see if we need to update the LSDB with the neighbor’s LSDB, to see if we need to send a link-state request or link-state update

Question 9

What are OSPF LSU packets?

Answer 9

Link state Update (LSU) packets are responses to a Link state request sent from some OSPF router and LSU packets are flooded across all the OSPF enabled listening routers. Throughout the OSPF domain.

Question 10

What are OSPF LSA or Link state acknowledgments?

Answer 10

These are acknowledgements to link state advertisements. Links state advertisements that gets received needs to get acknowledged.