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

The Database Description Packet

Database Description packets are OSPF packet type 2. These packets are exchanged when an adjacency is being initialized. They describe the contents of the topological database. Multiple packets may be used to describe the database. For this purpose a poll-response procedure is used. One of the routers is designated to be master, the other a slave. The master seconds Database Description packets (polls) which are acknowledged by Database Description packets sent by the slave (responses). The responses are linked to the polls via the packets’ DD sequence numbers.

Database Description Packet

Version No.

2

Packet Length

Router ID

Area ID

Checksum

 

Authentication Type

 

 

 

 

 

 

 

 

Authentication

 

 

 

 

 

 

 

 

Authentication

 

 

 

 

 

 

Reserved I M MS

Reserved

Options

 

 

 

DD Sequence No.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Link-State Advertisement Header ...

 

 

 

 

 

 

 

 

 

 

 

Figure 5-24. Database Description Packet

 

 

 

 

 

Field

Description

 

 

 

 

 

Options

The optional capabilities

 

 

 

supported by the router.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

146

 

Switch Management and Operating Concepts

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D-Link DES-3326S manual Database Description Packet, 146