D-Link DES-3326S manual Link-State Acknowledgment Packet, 150

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

Link-State Update Packet

Version No.

4 Packet Length

Router ID

Area ID

Checksum Authentication Type

Authentication

Authentication

Number of Advertisements

Link-State Advertisements ...

Figure 5-26. Link-State Update Packet

The body of the Link-State Update packet consists of a list of link-state advertisements. Each advertisement begins with a common 20-byte header, the link-state advertisement header. Otherwise, the format of each of the five types of link-state advertisements is different.

The Link-State Acknowledgment Packet

Link-State Acknowledgment packets are OSPF packet type 5. To make the folding of link-state advertisements reliable, flooded advertisements are explicitly acknowledged. This acknowledgment is accomplished through the sending and receiving of Link-State Acknowledgment packets. Multiple link-state advertisements can be acknowledged in a single Link-State Acknowledgment packet.

Depending on the state of the sending interface and the source of the advertisements being acknowledged, a Link-State Acknowledgment packet is sent either to the multicast address

150 Switch Management and Operating Concepts