Which of the following is an UDP based protocol?

Telnet uses TCP port 23 because it requires a reliable, connection-oriented session for interactive terminal communication.

SNMP (Simple Network Management Protocol) operates over UDP, using port 161 for requests and polling and port 162 for trap notifications. UDP is used because SNMP is designed for lightweight, low-overhead network monitoring where the application layer handles its own error management.

IMAP uses TCP port 143 because reliable, ordered delivery is required to maintain consistent mailbox state between client and server.

LDAP uses TCP port 389 because directory queries and updates require reliable, connection-oriented transport to ensure data integrity.