“A protocol used by Layer3 devices (like Routers) to discover neighbors and form adjacencies with each other” When a protocol process starts on a router, neighbors must be discovered and adjacencies must be established. Hello is a protocol which performs this duty. Hello protocol performs several functions, including but not limited to: It discovers neighbors (such as OSPF or IS-IS routers) It performs three-way handshaking to ensure bidirectional communication between the neighbors. It communicates information necessary for establishing whether an adjacency can be formed with a neighboring router After an adjacency is formed, it serves as a keepalive mechanism to … Continue reading Hello Protocol