Cisco OSPF 数据包类型指南

注：机翻，未校对。

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OSPF Packet Types: The Ultimate Guide 2024

OSPF Packet Types OSPF 数据包类型

There are five types of OSPF packets, namely- Hello, Database description, Link-state request, Link-state update and Link-state acknowledgement. Let’s discuss all these OSPF packet types in detail:
OSPF报文有五种类型，分别是Hello、数据库描述、链路状态请求、链路状态更新和链路状态确认。让我们详细讨论所有这些 OSPF 数据包类型：

1. THE HELLO PACKET : 1. hello包：

The hello packets are sent over a period of time on all interfaces for the purpose of establishing and maintaining neighbour relationships. Hello packets are multicast on the networks having multicast capability, which enables discovery of neighboring routers dynamically. The inhabitance of differences among hello packets can form neighbor relationships by agreeing certain parameters.
hello数据包在一段时间内在所有接口上发送，目的是建立和维护邻居关系。Hello 数据包是具有组播功能的网络上的组播，可以动态发现相邻路由器。hello数据包之间差异的驻留可以通过同意某些参数来形成邻居关系。

The purpose of Hello protocol can be summarized as follows:
Hello协议的目的可以概括为以下几点：

• Hello packets are used to discover OSPF neighbours.
  Hello 数据包用于发现 OSPF 邻居。
• Hello packets advertise certain parameters (some of the must match in order to become the router’s neighbor).
  Hello 数据包通告某些参数（其中一些参数必须匹配才能成为路由器的邻居）。
• On Broadcast or NBMA networks Hello packets are used to elect DR/BDR roles.
  在广播或 NBMA 网络上，Hello 数据包用于选择 DR/BDR 角色。
• Hello packets are used as a keepalive mechanism. If the router does not hear the neighbors’ Hello packets in a given time (DeadInterval), it considers it down and invalidates information obtained from it.
  Hello 数据包用作 keepalive 机制。如果路由器在给定时间 （DeadInterval） 内未听到邻居的 Hello 数据包，则认为该数据包已关闭并使从中获得的信息无效。
• Hello packets ensure bidirectional communication. The router must see its own RouterID in the ‘neighbor’ field of the Hello packet it receives.
  Hello 数据包确保双向通信。路由器必须在它收到的 Hello 数据包的“neighbor”字段中看到自己的 RouterID。

The Hello Packet Structure and fields information is detailed below –
Hello 数据包结构和字段信息详述如下 –

• Network Mask