application layer - chapter 3

Question 1

Name 5 of the protocols in application layer

Answer 1

1. SMTP
2. DNS
3. FTP
4. TELNET
5. HTTP

Question 2

Describe HTTP & port number

Answer 2

• Hypertext Transfer Protocol
• port: 80
• function . fetch html files from server
• how: client - initiates request
  server - receives request
  - fetch files
  - response request

Question 3

Describe SMTP & port number

Answer 3

• Simple Mail Transfer Protocol
• port: 25
• function: transfer & receive emails
• how:
  . clients initiates connection with SMTP
  . SMTP server safe keep email when received every copies
  . SMTP server then transfer email to host once establish a connection

Question 4

Describe FTP & Port number

Answer 4

• File Transfer Protocol
• port: 21
• function: file transfer
• how:
  . client initiates connection
  . server receives connection
  . server then transfer file to client

Question 5

Describe TELNET & port number

Answer 5

• port: 23
• function: allow configuration of routers, switches & etc (remote command line terminals)
• how:
  . client echoes characters
  . server echoes whole sentence once received whole line of characters.

Question 6

Describe DNS & port number

Answer 6

• Domain Name System
• port: 53
• function: translate host name into ip
• how
  . hierarchy based system
  . local - root - tld - organization (imagine searching words in a dictionary)