DES-3326S Layer 3 Fast Ethernet Switch User’s Guide

Loading The routers are finalizing the information exchange. Routers have link-state request list and a link-state retransmission list. Any information that looks incomplete or outdated will be put on the request list. Any update that is sent will be put on the retransmission list until it gets acknowledged.

Full The adjacency is now complete. The neighboring routers are fully adjacent. Adjacent routers will have the same link-state database.

Adjacencies on Point-to-Point Interfaces

OSPF Routers that are linked using point-to-point interfaces (such as serial links) will always form adjacencies. The concepts of DR and BDR are unnecessary.

OSPF Packet Formats

All OSPF packet types begin with a standard 24 byte header and there are five packet types. The header is described first, and each packet type is described in a subsequent section.

All OSPF packets (except for Hello packets) forward link-state advertisements. Link-State Update packets, for example, flood advertisements throughout the OSPF routing domain.

OSPF packet header

Hello packet

Database Description packet

Link-State Request packet

The Link-State Update packet

Link-State Acknowledgment packet

140

Switch Management and Operating Concepts

Page 140
Image 140
D-Link DES-3326S manual Adjacencies on Point-to-Point Interfaces, Ospf Packet Formats, 140