What type of packet do Open Shortest Path First (OSPF) routers send to discover their neighbors?

OSPF routers use Hello packets to discover and maintain neighbor relationships within an OSPF domain. When an OSPF router starts up, it sends out Hello packets to all interfaces that are configured for OSPF. This process is essential for establishing adjacency with other OSPF routers on the same network link.

Hello packets contain important information, including the router’s OSPF priority, Dead Interval, and Router ID, among other parameters. These packets enable routers to discover other OSPF routers and determine if they are in the same area, facilitating the sharing of routing information. The regular exchange of Hello packets also helps ensure that the OSPF neighbors remain operational and can update each other on network changes.

The other types of packets mentioned, such as announcement or route packets, are not specific to the neighbor discovery process within OSPF. While broadcast can refer to the method in which Hello packets are sent in certain network environments (like broadcast or multicast), the actual type of packet used for neighbor discovery is specifically referred to as Hello. Thus, understanding the role of Hello packets in OSPF operations is key to grasping how OSPF builds and maintains its topology.