What are the applications of ASCII in network protocols

Applications of ASCII in network protocols:

1. HTTP Protocol:

• HTTP request lines and headers use ASCII encoding
• Status codes and status messages are ASCII text
• Example: HTTP/1.1 200 OK

2. SMTP (Simple Mail Transfer Protocol):

• Email headers use ASCII encoding
• Commands and responses are based on ASCII
• Example: HELO, MAIL FROM, RCPT TO

3. FTP (File Transfer Protocol):

• Control connection uses ASCII commands
• Example: USER, PASS, LIST, RETR

4. Telnet Protocol:

• All commands and responses use ASCII
• NVT (Network Virtual Terminal) is based on ASCII

5. URL Encoding:

• Letters and numbers in URLs use ASCII
• Special characters use percent encoding (%XX)
• Example: Space is encoded as %20

6. MIME Types:

• Content-Type headers use ASCII
• Example: text/html; charset=utf-8

7. JSON Format:

• JSON strings use ASCII characters
• Non-ASCII characters use Unicode escape sequences
• Example: \u4e2d\u6587 represents "中文"

8. Base64 Encoding:

• Based on ASCII character set (A-Z, a-z, 0-9, +, /)
• Used for binary data transmission
• Example: SGVsbG8gV29ybGQ= represents "Hello World"

Advantages:

• Good cross-platform compatibility
• Easy to debug and parse
• Reduces encoding conversion overhead

Important Notes:

• Modern protocols support UTF-8
• Pay attention to byte order issues
• Non-ASCII characters need escaping