What protocol does the ping utility use to test connectivity?

What protocol does the ping utility use to test connectivity?

• A. UDP
• B. TCP
• C. ICMP
• D. ARP

Answer: (C)

Ping tests connectivity via ICMP, a message-based protocol at the Internet Layer. It sends an ICMP Echo Request to the destination and waits for an ICMP Echo Reply, and the round-trip time helps indicate reachability and latency. ICMP is designed specifically for diagnostic messaging and sits directly atop IP, unlike TCP or UDP, which are transport-layer protocols that require ports and, for TCP, a connection handshake. ARP is used to map IP addresses to MAC addresses on the local network and isn’t used for end-to-end connectivity testing. So the protocol used by ping is ICMP.

Ping tests connectivity via ICMP, a message-based protocol at the Internet Layer. It sends an ICMP Echo Request to the destination and waits for an ICMP Echo Reply, and the round-trip time helps indicate reachability and latency. ICMP is designed specifically for diagnostic messaging and sits directly atop IP, unlike TCP or UDP, which are transport-layer protocols that require ports and, for TCP, a connection handshake. ARP is used to map IP addresses to MAC addresses on the local network and isn’t used for end-to-end connectivity testing. So the protocol used by ping is ICMP.