Network Standard Protocols and Application Layer Protocols Notes

Network Standard Protocols

• Standards: Documented agreements that contain technical specifications for product or service design and performance.

Common Standardization Organizations

• Institute of Electrical and Electronics Engineers (IEEE)

  • International society of engineering professionals.

  • Prominent for LAN technology standardization (e.g., Ethernet, Token Ring, Wireless LAN).

  • Project 802 includes:

  • 802.3 - Ethernet

  • 802.5 - Token Ring

  • 802.11 - Wireless LAN.

• American National Standards Institute (ANSI)

  • Composed of over a thousand representatives from industry and government.

  • Known for standards like ASCII and SCSI.

• Electronic Industries Alliance (EIA)

  • Trade organization for electronics manufacturing in the U.S.

  • Writes ANSI standards and legislation beneficial to the computer and electronic industries.

• Telecommunications Industry Association (TIA)

  • Focuses on standards for IT, wireless, satellite, fiber optics, and telephone equipment.

  • Known for installation guidelines, such as the TIA/EIA 568 – B Series.

• Internet Engineering Task Force (IETF)

  • Responsible for overall internet development and internetworking technologies.

  • Components include:

  • Internet Society (ISOC): oversees overall internet development.

  • Internet Engineering Steering Group (IESG): oversees IETF activities and standard updates.

  • Internet Architecture Board (IAB): advisory group for ISOC on internet protocols and architecture.

  • Internet Assigned Numbers Authority (IANA): manages IP addressing and unique internet parameters.

• Organization for Standardization (ISO): An international standards organization responsible for a broad range of standards related to networking.

Application Layer Protocols

• The application layer provides interfaces for application software utilizing network services. It designates transport layer protocols and ports.

Key Protocols

• Simple Mail Transfer Protocol (SMTP): Protocol for reliable electronic mail transfer.

• Post Office Protocol version 3 (POP3): Protocol for retrieving mail from servers.

• Trivial File Transfer Protocol (TFTP): Simple file transfer alternative to FTP using UDP.

• File Transfer Protocol (FTP): Protocol enabling file sharing between systems using TCP for control and data connections.

• Network File System (NFS): Allows computers to mount remote drives as local.

• Domain Name System (DNS): Translates domain names into IP addresses.

• Simple Network Management Protocol (SNMP): Enables network management by facilitating monitoring and controlling network devices.

  • Components:

  • Managed Devices

  • Agents

  • Network Management Systems (NMS)

• Telnet: Protocol for terminal emulation over TCP.

• rlogin: UNIX command for remote login to network hosts.

• Hypertext Transfer Protocol (HTTP): Protocol for information exchange on the web.

• HTTPS: Secure version of HTTP using Secure Sockets Layer (SSL) for encryption.

TCP and UDP Connections

• Computers communicate over the Internet using either TCP or UDP.

Transmission Control Protocol (TCP)

• Connection-oriented protocol providing reliability, error detection, and flow control.

• Relies on acknowledgment of data received.

User Datagram Protocol (UDP)

• Connectionless protocol providing an unreliable, best-effort service for sending packets without guarantee of delivery.

Port Numbers

• Data transmission includes 32-bit IP addressing and 16-bit port addressing.

• Ports range from 0 to 65,535:

  • 0 - 1023: Reserved for well-known services such as:

  • 21 (FTP)

  • 23 (Telnet)

  • 25 (SMTP)

  • 80 (HTTP)

TCP and UDP Header Fields

• TCP Header Fields:

  • Source and Destination Port (16 bits each)

  • Sequence Number (32 bits)

  • Acknowledgment Number (32 bits)

  • Header Length (4 bytes)

  • Control Bits (FIN, ACK, SYN)

  • Window (flow control)

  • Checksum (error-checking)

• UDP Header Fields:

  • Source and Destination Port (16 bits each)

  • Length (min 8 bytes)

  • Checksum (error-checking)

SYN-ACK Handshake

• Three-Way Handshake:

  • Initializes a connection before data transmission:

  • SYN (Synchronize)

  • ACK (Acknowledge)

  • FIN (Finish)

TCP Data Transmission Control

• Uses a sliding window mechanism for flow control to manage the data transmission rate.

TCP Shutdown

• Four-Way Handshake: Engaged to safely disconnect a TCP connection and release resources.