Network Protocol of Computer network

Basic concepts

A set of rules, standards, or conventions established by network protocols for data exchange in a computer network.

Elements

The network protocol consists of three elements:

(1) Semantics。 Semantics is the interpretation of the meaning of each part of the control information. It specifies what kind of control information needs to be emitted, as well as the actions performed and what responses are made. (2) Grammar。 syntax is the structure and format of user data and control information, and the order in which the data appears. (3) Timing。 Timing is a detailed description of the order in which events occur. (also referred to as "Synchronization"). The three elements are depicted as: what the semantics mean to do, what the syntax means to do, and the order in which the timings are made. Working style

How do you exchange information between computers on the network? Just as we speak in a language, there is also a language between computers on the network, which is the network protocol that must be used by the same network protocol to communicate between different computers.

The network protocol is a collection of communication rules between all the devices on the network (network servers, computers and switches, routers, firewalls, etc.), which specifies the format to be used for communication and the meaning of these formats. Most networks have a layered architecture, each layered on top of it, providing some service to its upper layer, and masking the details of how to implement the service.

There are many protocols in each layer of the network, and the receiver and sender must agree on the same layer, otherwise one party will not be able to identify the information sent by the other party. Network protocols enable various devices on the network to exchange information with each other.

Hierarchical Division

In order to enable computers from different computer manufacturers to communicate with each other in order to build up a computer network in a larger context, the International Organization for Standardization (ISO) introduced the "Open Systems Interconnection Reference Model" in 1978, the famous OSI/RM model (open system Interconnection/reference Model). It divides the communication protocol of the computer network architecture into seven layers, from bottom to top: the physical layer (Physics layer), the data link layer, the network layer, the Transport layer (Transport layer), Session layer, Presentation layer (Presentation layer), Application layer (application layer).

Application Layer

Presentation Layer

Session Layer

Transport Layer

Network layer

Data Link Layer

Physical Layer

Dividing the physical layer: Ethernet · Modem Power line Communication (PLC) · SONET/SDH g.709Optical Fiber • Coaxial cable • Twisted pairsuch as number according to the link layer:Wi-Fi (IEEE 802.11)· WiMAX (IEEE 802.16) · ATM DTMToken Ring • Ethernet· FDDI Frame Relay · GPRS EVDO HSPA HDLC PPP L2TP PPTP ISDN Network layer protocols such as STP:IP (IPv4 IPV6) · ICMP ICMPv6 IGMP Is-is IPSec ARP Rarp and other transport layer protocols:TCP UDPTLS DCCP SCTP RSVP Application layer protocols such as OSPF: DHCPDNS FTP· GopherhttpIMAP4 IRC NNTP Xmpp· POP3· SIP SMTP SNMP SSH Telnet RPC RTCP RTP RTSP SDP Soap GTP Stun NTP SSDP BGP RIP, etc.

Network Protocol of Computer network