TCP/IP - Internet Protocol Suite and Ethernet

International Standard Organization's Open System Interconnection Reference Model

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• A reference model, not a rigid specification.
• Layered-Structure: Clearly-defined functionality for each layer and interfeace between layers facilitate independent implementation.
• Data Encapsulation: Headers carrying related information are added to packages as packages go down from upper layer to lower layer. The process is reversed at destination.
• Peer-to-Peer Communication: Each layer focuses only on the package content at correspondent layer.

OSI Model, DoD Model, and TCP/IP Protocol Suit

TCP/IP over Ethernet

Transport Layer - User Datagram Protocol (UDP)

• Connection-less, no error control, no flow control.
• UDP header carries information on Source Port, Destination Port, and others.
• Send data directly without establishing connection.
• A sample package from UDP_Message_Sender.zip to UDP_Message_Receiver.zip captured using CommView.
  

Transport Layer - Transmission Control Protocol (TCP)

• Connection-based, with error control and flow control
• TCP header carries information on Source Port, Destination Port, Sequence Number, Acknowledge Number, Control Flags, Window, and others.
• Sequence Number and Acknowledge Number are for error control and dealing with out-of-order packages, Window is for flow control, and Control Flags are for connection control.
• Establish connection before sending / receiving data:
  • 
  • Sample packages for making connection from TCP_Messager_Sender.zip to TCP_Messager_Receiver.zip captured using CommView.
    Packet 1, Packet 2, Packet 3
• Send data while connected:
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  • Sample packages for sending data from TCP_Messager_Sender.zip to TCP_Messager_Receiver.zip captured using CommView.
    
    Packet 4, Packet 5
    
• Close Connection after Use
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  • Sample packages for TCP_Messager_Sender.zip disconnecting from TCP_Messager_Receiver.zip captured using CommView.
    Packet 6, Packet 7, Packet 8, Packet 9
    

Internet Layer - Internet Protocol (IP)

• IP header carries information on Source IP Address, Destination IP Address, Protocol, routing information, and others.
• ARP (Address Resolution Protocol) is a sub-protocol dealing with the mapping between IP Address and MAC Address.
• DHCP (Dynamic Host Configuration Protocol) is sub-protocol for dynamic IP Address assignment.

Network Access Layer - Ethernet

• Ethernet header carries information on Source MAC Address, Destination MAC Address, Ethertype, and others.
• MAC (Media Access Control) Address is an unique idetifier for each network device.
• CSMA/CD: Carrier Sense Multiple Access with Collision Detection.

Wiring and Network Devices

• UTP (Unshielded Twisted Pair) Category 5, RJ-45
  • Pin Configuration
  • Patch Cord (1-1, 2-2, 3-3, 6-6) for Hub-to-PC and Hub Cascading
  • Crossover Cord (1-3, 2-6, 3-1, 6-2) for PC-to-PC and Hub Shunting
• Network Interface Card
• Hub, Switching Hub
• Transducer
• Router

Request For Comments

• RFC