TCPIP Protocol Suite

Last Updated on Fri, 30 Jun 2023 | Ospf Network

A protocol is a set of rules and conventions that govern how devices on a network exchange information. This section discusses one of the more commonly used protocol suites: TCP/IP. This discussion does not provide sufficient information for an in-depth study of TCP/IP. Nevertheless, TCP/IP needs to be covered to some degree so that you can better understand the overall operation of network protocols; these discussions are expanded in later chapters concerning OSPF.

The TCP/IP protocol suite is also referred to as the TCP/IP stack, and it is one of the most widely implemented internetworking standards in use today. The term TCP/IP literally means Transmission Control Protocol/Internet Protocol. TCP and IP are the two core protocols that exist within the TCP/IP protocol suite, and their place in the TCP/IP protocol stack is clarified in the following paragraphs.

TCP/IP was originally developed for ARPAnet, a U.S. Government packet-switched WAN, over 25 years ago. Although at the time, the Internet was a private network and TCP/IP was designed specifically for use within that network, TCP/IP has since grown in popularity and is one of the most open protocols available for use in networks today. This growth and popularity is primarily due to TCP/IP's capability to connect different networks regardless of their physical environments. This has made TCP/IP today's de facto standard on the Internet and in the majority of today's networks, large and small.

TCP/IP is not 100 percent compatible with the OSI reference model; however, TCP/IP can run over OSI-compliant lower layers, such as the data link and physical layers of the OSI model. TCP/IP can communicate at the network layer as well using IP. Essentially, layers 3 and below in the OSI reference model are close to the original TCP/IP structure. Figure 1-5 illustrates this mapping of layers between the OSI model and the TCP/IP protocol.

Figure 1-5 OSI Model-to-TCP/IP Mappings

OSI Model

TCP/IP Model

OSI Model

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/

7

Application

/

6

Presentation

/

5

Session

/

4

Transport

3

Network

2

Data Link

1

Physical

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Application

Transport

Network

Data Link

Physical

TCP/IP Protocol Suite 15

TCP/IP Functions

Whereas OSI was a structure for networks, you can consider TCP/IP the language of the networks. When combined, networks create a diverse and powerful network—the Internet. This section reviews the major functionality of TCP/IP in general and then TCP and IP in turn.

The term segment describes a unit of data at the TCP layer. At the IP layer, it is called a packet, and at the lower layers, it is called a frame. The various names are shown in Figure 1-3.

If a message is too large for the underlying network topology, it is up to the IP layer to fragment the datagram into smaller parts. For example, Ethernet frame sizes differ from what is allowable in Token Ring; therefore, IP handles the size changes as needed.

Different paths might be available through the Internet, between a source and a destination station. Fragments of a datagram might take different paths through a network. So, when messages arrive at the destination station, the IP protocol stack must sequence them and reassemble them into their original datagram. Each datagram or fragment is given an IP header and is transmitted as a frame by the lower layers.

NOTE In addition to the two network layer protocols (IP and Internet control message protocol

[ICMP]) and the two transport layer protocols (TCP and UDP), the TCP/IP suite includes a cluster of protocols that operates at the upper layers, such as FTP, Telnet, and so on. Some of these are TCP/IP-specific, and some are protocols that can run with TCP/IP but originate elsewhere; however, discussion of these advanced protocols is beyond the scope of this book.

A good resource for further reading on the subject of TCP/IP is TCP/IP Illustrated, Volume 1, by Richard Stevens. It is somewhat dated in its examples, but the text is definitive. Also, by the time you read this, Stevens's second edition should be published. Hopefully, the high standards of the original volume will be maintained because Mr. Stevens has regretfully passed away and did not revise the first edition.

TCP Overview

Within this suite of protocols, TCP is the main transport layer protocol that offers connection-oriented transport services. TCP accepts messages from upper-layer protocols and provides the messages with an acknowledged reliable connection-oriented transport service to the TCP layer of a remote device. TCP provides five important functions within the TCP/IP protocol suite:

• Provides format of the data and acknowledgments that two computers exchange to achieve a reliable transfer

• Ensures that data arrive correctly

• Distinguishes between multiple destinations on a given machine

16 Chapter 1: Networking and Routing Fundamentals

Explains how to recover from errors

Explains how a data stream transfer is initiated and when it is complete

IP Overview

IP is the main network-layer protocol. It offers unreliable, connectionless service because it depends on TCP to detect and recover from lost packets when TCP is being used. Alternatively, when UDP is used, there is no recovery of lost packets because UDP does not have that capability. IP provides three important functions within the TCP/IP protocol suite:

• Defines the basic format and specifications of all data transfer used throughout the protocol suite

• Performs the routing function by choosing a path to the required destination over which data is to be sent

• Includes the previously mentioned functions as well as those covering unreliable packet delivery

Essentially, these functions cover how packets should be processed, what error message parameters are, and when a packet should be discarded.

Continue reading here: Types of Network Topologies

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Readers' Questions

  • topi
    What is tcp ip used for?
    1 month ago
    • TCP/IP (Transmission Control Protocol/Internet Protocol) is a set of networking protocols that enables two or more computers to communicate over a network. It is the foundation of internet communications and the standard for most business networks. TCP/IP allows users to send information across a network, allows different networks to join together, and provides reliable data delivery. TCP/IP is used for data transmission between computers, printers, and other internet devices, and it also enables data to travel securely over the internet.
    • ADELMO
      What layer in the transmission control protocol/internet protocol (tcp/ip) model does ip use?
      1 month ago
      • IP (Internet Protocol) operates at the network layer in the TCP/IP model.
      • teresa
        Which layer in the transmission control protocol/internet protocol (tcp/ip) model does ip use?
        1 month ago
        • In the Transmission Control Protocol/Internet Protocol (TCP/IP) model, IP (Internet Protocol) is in the network layer or the Internet layer.
        • DEMET GIRMA
          What is tcp ip used for?
          2 months ago
          • TCP/IP is an acronym for Transmission Control Protocol/Internet Protocol, which is the suite of communications protocols used to connect hosts on the Internet. TCP/IP enables the exchange of information between computer systems on different networks. It can also be used as a communications protocol in a private network.
          • Rezene
            What layer in the transmission control protocol/internet protocol (tcp/ip) model does ip use?
            2 months ago
            • IP uses the Network Layer, which is the third layer of the TCP/IP model.
            • charles
              What is tcp ip used for?
              3 months ago
              • TCP/IP is a suite of communication protocols used to interconnect network devices on the internet. It provides end-to-end communications and is the foundation for most of the data traffic over the internet. It is used for many applications and protocols including email, file transfer, remote login, streaming media, and Voice over Internet Protocol (VoIP) calls.
              • Speranza
                Which tcp/ip layer deals the security of message?
                3 months ago
                • The Transport layer (Layer 4) of the TCP/IP model is responsible for the security of messages in a network. It provides authentication, data integrity, and confidentiality through different protocols such as Secure Socket Layer (SSL), Transport Layer Security (TLS), and Secure Shell (SSH). These protocols ensure that data is encrypted before transmission, and decrypted after receiving, thus providing security of messages in a network.
                • rowan proudfoot
                  What layer in the transmission control protocol/internet protocol (tcp/ip) model does ip use?
                  3 months ago
                  • IP uses the Network layer (Layer 3) of the TCP/IP model.
                  • tom
                    What is tcp ip used for?
                    4 months ago
                    • TCP/IP (Transmission Control Protocol/Internet Protocol) is the language a computer uses to access the internet. It can be used for communication between devices on a network, to access websites, and to send/receive data over the internet. It is the foundation for most internet communication and essential for the modern connected world.
                    • michelle
                      Which of the following is the core communications protocol for the internet?
                      4 months ago
                      • The core communications protocol for the Internet is the Transmission Control Protocol/Internet Protocol (TCP/IP).
                      • Abdullah
                        What tcp/ip protocol is fast, unreliable, and operates at the transport layer?
                        5 months ago
                        • ? UDP (User Datagram Protocol) is a fast, unreliable protocol that operates at the transport layer.
                        • primula
                          What is protocol what are the main functions of tcp/ip?
                          7 months ago
                          • Protocol: A protocol is a set of rules and standards that govern how machines communicate with each other. Main Functions of TCP/IP:
                          1. Establishing Connections: TCP/IP uses synchronization and connection establishment protocols (e.g. SYN, ACK, FIN) to establish reliable connections between two hosts over a network.
                          2. Data Transfer: TCP/IP also defines the data transport layer, which is responsible for segmenting, sequencing, and reassembling data packets.
                          3. Error Detection and Recovery: TCP/IP defines various error detection and correction techniques to ensure effective data transfer over a network.
                          4. Network Addressing: TCP/IP uses IP addressing to ensure data is routed to the right destination.
                          5. Flow Control: TCP/IP also uses flow control techniques to ensure data is not sent too fast or slow over a network.
                          6. Congestion Control: TCP/IP incorporates congestion control algorithms so network performance is not affected by high traffic.
                          • clinton wicker
                            What is tcp ip used for?
                            7 months ago
                            • TCP/IP (Transmission Control Protocol/Internet Protocol) is a set of communications protocols that is used to connect devices on the Internet. It is the underlying technology that enables the transfer of data between computers on the Internet, as well as other networks. It is the most widely used network protocol in the world, powering the majority of the Internet, including major websites and services.
                            • Urho Piili
                              What is tcp ip used for?
                              7 months ago
                              • TCP/IP (Transmission Control Protocol/Internet Protocol) is a suite of communication protocols used to connect devices on a network. It enables two or more computers to communicate over a network, allowing them to share resources such as files, printers, and other information. It also provides guidelines for formatting data so that every device on a network can understand it.
                              • Tanja Hirvi
                                What are the two main services provided by the network layer of the tcp/ip model?
                                7 months ago
                                • The two main services provided by the network layer of the TCP/IP model are:
                                1. Logical addressing (IP addressing): This service is used to uniquely identify a host on a network.
                                2. Routing: This service is responsible for transferring data packets from source host to destination host across multiple networks.
                                • sabrina
                                  What is tcp ip used for?
                                  7 months ago
                                  • TCP/IP (Transmission Control Protocol/Internet Protocol) is the language that computers use to communicate over the internet. It is the foundation for data communication for the entire internet, allowing different computer systems to communicate with each other. It is used for a wide range of purposes, including file sharing, email, streaming media, and teleconferencing.
                                  • riitta narjus
                                    What is an example of a device that works at the network layer of the tcp/ip stack?
                                    7 months ago
                                    • A router is an example of a device that works at the network layer of the TCP/IP stack. Routers are responsible for routing traffic between networks and forwarding packets based on IP addresses.
                                    • Teighan
                                      What three application layer protocols are part of the tcp/ip protocol suite?
                                      7 months ago
                                      1. Hypertext Transfer Protocol (HTTP)
                                      2. File Transfer Protocol (FTP)
                                      3. Simple Mail Transfer Protocol (SMTP)
                                      • annett
                                        Which of the following layers is not part of the tcp/ip protocol stack?
                                        7 months ago
                                        • Application Layer
                                        • herugar chubb-baggins
                                          What is tcp ip used for?
                                          7 months ago
                                          • TCP/IP (Transmission Control Protocol/Internet Protocol) is a set of communication protocols used to connect devices on the internet. It is the foundation of data communication for the internet and enables two or more computers to connect and share data. TCP/IP is used to enable data transfer between two or more devices, typically a server and a client, and can be used for communication protocols like email, file transfer, web browsing and more.
                                          • markus
                                            What can be defined as a private network that uses tcp/ip protocols?
                                            7 months ago
                                            • A Virtual Private Network (VPN) is a private network that uses Internet protocols, such as TCP/IP, to create a secure connection between two or more computers. A VPN provides a secure, encrypted tunnel for transmitting data between two nodes, often across public networks such as the Internet.
                                            • pontus
                                              What is tcp ip used for?
                                              8 months ago
                                              • TCP/IP (Transmission Control Protocol/Internet Protocol) is the foundation of the Internet and computer networking in general. It is a suite of protocols that provides communication between devices connected to the Internet. It enables two or more devices to communicate over a network by exchanging packets of data. Applications such as email, file transfer, web browsing, streaming audio and video, and virtual private networks all rely on TCP/IP to communicate.
                                              • polo
                                                What are the major tcp/ip protocols in use today?
                                                8 months ago
                                                • The major TCP/IP protocols in use today are:
                                                1. Transmission Control Protocol (TCP)
                                                2. User Datagram Protocol (UDP)
                                                3. Internet Protocol (IP)
                                                4. Hypertext Transfer Protocol (HTTP)
                                                5. File Transfer Protocol (FTP)
                                                6. Simple Mail Transfer Protocol (SMTP)
                                                7. Secure Shell (SSH)
                                                8. Telnet
                                                9. Internet Control Message Protocol (ICMP)
                                                10. Address Resolution Protocol (ARP)
                                                • Simone
                                                  What is the de facto protocol suite of the internet?
                                                  8 months ago
                                                  • The de facto protocol suite of the internet is the Transmission Control Protocol/Internet Protocol (TCP/IP).