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TCP/IP model (Fact Standard Layer 4)

The TCP/IP model consists of the network interface layer (corresponding to the physical layer and the data link layer in the OSI model), the Internet layer, the transport layer and the application layer (corresponding to the session layer, the presentation layer and the application layer in the OSI model).

  1. Network interface layer

    Represents an interface to the physical network, merely indicating that the host must use some protocol to connect to the network. Specific physical networks can be lans of various types or public data networks. The role of the network interface layer is to receive IP packets from hosts or nodes and send them to the specified physical network

  2. Internet Layer (host – Host)

    The Internet layer is a key part of the TCP/IP architecture. The Internet layer sends packets to any network and independently selects suitable routes for them, but it does not guarantee the orderly arrival of each packet. The orderly delivery of each packet is the responsibility of the higher level. The Internet layer defines the standard grouping format and protocol, IP. The current IP protocol is IPv4.

  3. Transport layer (application – application or process – process)

    Enables a session between peer entities on the sending and destination hosts. Two main protocols are used:

    1. Transmission Control Protocol (TCP):connection-orientedThe unit of data transmission isMessage segment, can provide reliable delivery
    2. User Datagram Protocol (UDP):There is no connectionThe unit of data transmission is the userThe datagramReliable delivery is not guaranteed
  4. Application layer (user-user)

    Includes all high-level protocols

Note: IP protocol is the core protocol in the Internet. TCP/IP allows the IP protocol to run over the Internet, which is made up of various networks

  • Comparison between TCP/IP model and OSI model

    Similarities:

    • Both adopt a layered architecture
    • Both are based on the concept of a separate protocol stack
    • Can realize heterogeneous network interconnection

    Difference:

    • OSI defines three points: services, protocols, and interfaces

    • OSI came first, the reference model was invented before the protocol, not biased towards a particular protocol

    • TCP/IP Considers IP as an important layer for heterogeneous network interconnection

    • OSI model supports connectionless and connection-oriented communication at the network layer, but only connection-oriented communication at the transport layer. The TCP/IP model only has connectionless communication at the network layer, but supports connectionless and connection-oriented communication at the transport layer

  • 5 layers of reference model