Cisco Certified Network Associate (CCNA) Practice Exam

Which EIGRP packet type is responsible for establishing and maintaining neighbor relationships?

1. Update Packet

2. Query Packet

3. Hello Packet

4. Acknowledgment Packet

The correct answer is: Hello Packet

The Hello Packet is the type of EIGRP packet responsible for establishing and maintaining neighbor relationships. In the EIGRP protocol, Hello Packets are sent periodically between routers to discover other EIGRP routers on the network and to maintain the adjacency with those routers. This packet plays a crucial role in the formation of the EIGRP topology and in ensuring that routers can communicate effectively. Hello Packets contain information such as the EIGRP router's hold time and the multicast address used to send the packets. By exchanging Hello Packets, routers can determine which other routers are reachable and within what time frame they need to hear from their neighbors to maintain their relationships. If a router does not receive a Hello Packet from a neighbor within the configured hold time, it assumes that the neighbor is no longer available and may remove it from its routing table. The other types of packets serve different functions within EIGRP. Update Packets are used to send routing information between routers, while Query Packets are sent to discover routes that are not known within the EIGRP domain. Acknowledgment Packets are used to confirm the receipt of Update Packets, ensuring reliable delivery of routing information, but they are not directly involved in neighbor relationship management.