Chapter 3. OSPF Theory and Operation

Open Shortest Path First (OSPF) Protocol is a widely used advanced link-state routing protocol. This chapter provides a high-level overview of the theory and operation of OSPF.

Neighbor Relationships

OSPF forms neighbor relationships for two primary reasons:

• To discover links along which traffic may be forwarded in the network (edges in the shortest-path tree)

• To provide for the reliable transmission of routing information through the network

OSPF uses a three-way handshake process to form neighbor relationships, as shown in Figure 3-1.

FIGURE 3-1 OSPF Neighbor Formation

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OSPF will not form a neighbor relationship ...

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