Hello Packet

<networking, communications> An OSPF packet sent periodically on each network interface, real or virtual, to discover and test connections to neighbours. Hello packets are multicast on physical networks capable of multicasting or broadcasting to enable dynamic router discovery. They include the parameters that routers connected to a common network must agree on.
Hello packets increase network resilience by, e.g., allowing a router to establish a secondary connection when a primary connection fails.
(1999-11-02)