Cisco CCNA mock exam questions sample test – Question 178

.Which Enhanced Interior Gateway Routing Protocol (EIGRP) packet is NOT sent reliably over the network?

A. Update
B. Query
C. Reply
D. Acknowledgement

Correct Answer: D

Explanation:
Acknowledgement packets are sent unreliably over the network, and there is no guaranteed delivery of acknowledgement packets between neighboring routers.
Acknowledgement packets are a special type of hello packets that do not contain data and have a non-zero acknowledgement number. These are sent as a unicast.
Update, Query, and Reply packets use Reliable Transport Protocol (RTP), which ensures guaranteed delivery of packets between neighboring devices. The RTP mechanism ensures
loop-free synchronized network.
Objective:
Routing Fundamentals
Sub-Objective:
Configure, verify, and troubleshoot EIGRP for IPv4 (excluding authentication, filtering, manual summarization, redistribution, stub)
References:
Internetworking Technology Handbook > Enhanced Interior Gateway Routing Protocol (EIGRP)