TCP/IP and OSI Model Overview

Introduction

• TCP/IP (Transmission Control Protocol/Internet Protocol) is a fundamental protocol suite used for communication on the Internet and intranets.
• TCP/IP is based on the Department of Defense (DOD) model.

IP (Internet Protocol)

• IP is a network layer protocol responsible for addressing and routing data packets across networks.
• IP defines a logical addressing scheme (IP addresses) for devices.
• Examples of network layer protocols: RIP, OSPF, EIGRP, IS-IS
• Examples of routed protocols: IP, Apple Talk, IPX (Internetwork Packet Exchange)
• Examples of message and control protocols: ICMP (Internet Control Message Protocol), Error Message, Ping, Traceroute
• ARP (Address Resolution Protocol) is used to translate logical IP addresses to physical MAC addresses.

TCP (Transmission Control Protocol)

• TCP provides reliable and ordered delivery of data segments.
• TCP uses a three-way handshake to establish a connection between two devices.

OSI (Open Systems Interconnection) Model & TCP/IP Relationship

• The OSI model is a theoretical framework that defines seven layers of network communication.
• TCP/IP maps to the OSI model but does not strictly follow all its layers.

Network Access Layer

• The Network Access Layer is responsible for the physical transmission of data over a network medium.
• Examples of LAN protocols: Ethernet, Token Ring, ARC-NET
• Examples of WAN protocols: HDLC, PPP, ISDN, Frame Relay, ATM
• MAC addresses are physical addresses that uniquely identifies a device on a network.
• The Network Access Layer converts binary data into signals suitable for the network media.

TCP Segment Header Fields

• Source port number: Specifies the port number of the sending device.
• Destination port number: Specifies the port number of the receiving device.
• Total Length: Indicates the total length of the TCP segment (header + data).
• Checksum: Ensures data integrity during transmission by performing an arithmetic operation on the segment.

TCP Segment Header Fields for Connection Management

• Sequence number: Identifies individual data segments and facilitates in order delivery.
• Acknowledgment number: Confirms receipt of segments from the sender.
• DO: Shows the size of the TCP header.
• RSV: Reserved field for future use.
• Flags: Control bits that manage the connection state and data transfer.
• Window: Specifies the allowed number of segments that can be sent without acknowledgment.

Ethernet Frame Structure

• Preamble: Contains a synchronization pattern that allows the receiver to identify the start of a frame.
• Start of Frame Delimiter (SOF)/Synch: Marks the beginning of the frame.
• Destination Address (DA): 48-bit MAC address of the intended recipient.
• Source Address (SA): 48-bit MAC address of the transmitting device.
• Length or Type: Specifies the total length of the frame or indicates the upper layer protocol.
• Data: Data payload from the Network layer.
• Frame Check Sequence (FCS): CRC value used for error detection.

Token Ring Network

• Devices in a token ring network are connected in a closed loop, creating a circular path for data transmission.
• A special token circulates around the ring.
• A device can transfer data only when it possesses the token.

ARC-NET

• A token passing network, using UTP or fiber optic cables.

Ethernet Network

• Ethernet uses a contention-based media access method called Carrier Sense Multiple Access with Collision Detection (CSMA/CD).
• Devices share the same bandwidth.
• Collisions can occur when multiple devices attempt to transmit simultaneously.
• Collision domains are network segments where a collision can occur.
• Broadcast domains are network segments where broadcasts can reach all devices.

Star Topology

• Devices are connected to a central hub, switch, or access point.
• Offers better fault tolerance compared to bus topology.
• Offers easier troubleshooting.

This quiz covers the fundamental concepts of TCP/IP and the OSI model, including the roles of different protocols such as IP and TCP in data communication. Understand how addressing, routing, and reliable delivery mechanisms work in network communications. Test your knowledge on key protocols and their functions within the internet architecture.