Question

Which of the following application layer protocols correspond with both UDP & TCP:

a) DNS
b) DHCP
c) FTP
d) HTTP
e) SMTP
f) SNMP
g) TFTP

Answer 1

Of the listed application layer protocols, DNS (Domain Name System) is the one that corresponds with both UDP and TCP as it uses UDP for queries and TCP for larger transfers or when zone files are involved.

Step-by-step explanation:

The question concerns which application layer protocols use both UDP (User Datagram Protocol) and TCP (Transmission Control Protocol). These protocols define methods by which data is sent across a network. Looking at the list provided:

• a) DNS - Domain Name System can use both TCP and UDP. UDP is commonly used for query requests, while TCP is used for transferring zone files and for queries that require a larger data transfer.
• b) DHCP - Dynamic Host Configuration Protocol only uses UDP.
• c) FTP - File Transfer Protocol uses only TCP.
• d) HTTP - Hypertext Transfer Protocol uses only TCP.
• e) SMTP - Simple Mail Transfer Protocol uses only TCP.
• f) SNMP - Simple Network Management Protocol primarily uses UDP, but there are cases where TCP may be used as well.
• g) TFTP - Trivial File Transfer Protocol uses only UDP.

Therefore, from the options provided, DNS is the protocol that clearly corresponds with both UDP and TCP.