What kind of packets does EIGRP use to communicate with neighbors during the establishment of adjacency?

EIGRP, or Enhanced Interior Gateway Routing Protocol, utilizes hello packets as its primary means of establishing adjacency with neighboring routers. When a router wants to establish a neighbor relationship, it sends hello packets to discover other EIGRP routers in the network. The hello packets contain essential information, such as the hold time, the router's EIGRP process ID, and other parameters needed for successful communication.

Once the target router receives the hello packet, it verifies the received information and can respond back, which is crucial for forming and maintaining adjacency. This process allows routers to exchange information about their networking capabilities and their respective states, ensuring that they can communicate effectively for routing purposes.

This is distinct from other types of EIGRP packets, such as update packets, which are used to share routing information after adjacency is established, acknowledgment packets, which confirm the receipt of other packet types, and query packets, which are utilized to solicit information from neighboring routers under specific circumstances.