注：机翻，未校对。

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OSPF Type2 Message / DBD Packet (Database Descriptor)

DBD (Database Description or Type2 OSPF Packet) is a sort of summary of the OSPF Database in a router. DBD is used to check if the LSDB between 2 routers is the same.
DBD（数据库描述或 Type2 OSPF 数据包）是路由器中 OSPF 数据库的一种摘要。DBD 用于检查两个路由器之间的 LSDB 是否相同。

These packets are exchanged when an adjacency is being initialized. They describe the topology information a router has in its database. DBD uses poll-response procedure (master/slave). Master sends DBD packets/polls which are acknowledged by the slave.
这些数据包在初始化邻接关系时进行交换。它们描述了路由器在其数据库中的拓扑信息。DBD 使用轮询响应过程（主/从）。主服务器发送 DBD 数据包/轮询，这些数据包/轮询由从服务器确认。

Consider the simple below topology with two Routers:
考虑以下具有两个路由器的简单拓扑：

As soon as we enable OSPF on the router interfaces, it starts exchanging Hello and DBD Packets.
一旦我们在路由器接口上启用 OSPF，它就会开始交换 Hello 和 DBD 数据包。

It is obvious from the below detail, spend some time with it to understand it fully:
从下面的细节可以明显看出，花一些时间来充分理解它：

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via:

• OSPF Type2 Message / DBD Packet (Database Descriptor) - ATech Academy Written by Waqas Karim

  https://aurumme.com/atech/ospf-type2-message-dbd-packet-database-descriptor/