Shulou(Shulou.com)06/02 Report--

I. TCP / IP protocol

1.TCP/IP communication protocol is the most complete at present. The most widely supported communication protocol, which allows different network architectures. Communication between computers with different operating systems is the standard communication protocol of Internet.

two。 Three elements of communication between host and host

IP address (IP address)

Subnet Mask (subnet mask)

IP routing (IP router)

II. IP address

1. Function: used to identify the network address of a node

two。 Composition: 32 bits, represented by 4 decimal numbers, used in between. Separate

Network bit + host bit

3. Classification:

A 1 ~ 126 network + master

B 128 ~ 191 network + network + master + master

C 192 ~ 223 network + master

D 224 ~ 239 Multicast (Multicast)

E 240 ~ 254 scientific research

4. Default subnet mask

Class A 255.0.0.0

Class B 255.255.0.0

Class C 255.255.255.0

5. Gateway: a gateway that connects one network to another.

6. Public IP address and private IP address

Public address, also known as public network address, through which direct access to the Internet, it is within the scope of the wide area network.

Private address, also known as private network address, is used exclusively within the organization. It is within the scope of the local area network, and the Internet cannot be accessed outside the local area network.

Private address range:

Category A 10.0.0.1 ~ 10.255.255.254

Category B 172.16.0.1 ~ 172.31.255.254

Class C 192.168.0.1 ~ 192.168.255.254

3.

1 basic overview of computer network

Hardware:

In terms of software:

Realize the sharing of resources. Information transmission

2 the function of computer network

Data communication. Resource sharing. Increase the reliability of data. Improve the processing capacity of the system

3. The development of computer network

1960s: packet switching

1970s-1980s: TCP/IP

90 years later: Web Technology

4. Network protocols and standards:

1. Protocol: a set of rules that control data communication, the three elements of the protocol: syntax. Semantics, synchronization.

two。 Standard: the rule of consensus can be understood as a standard

ISO (International Organization for Standardization) created the OSI (Open Systems Interconnection) model in network communication.

ANSI (U.S. National Bureau of Standardization)

ITU-T (International Telecommunication Union-Telecommunication Standards Department)

IEEE (Institute of Electrical and Electronic Engineers)

5.WAN and LAN

WAN: Wan LAN: lan

6. Network equipment

An exchange. Router

Network security device: firewall. × × device

Wireless network equipment: wireless network card. Wireless router

Network equipment manufacturer: cisco Cisco, Huawei.

7 Network topology

1 point to point: there is a separate connection between the two Devic

2 bus type: early LAN topology, using coaxial cable

3 Ring: token Ring Network

4 star topology

Advantages: easy to implement. Easy to expand the network. Easy to troubleshoot

Disadvantages: the pressure on the central node is high. The cost of networking is high

5. Network topology

Each node is connected to at least two other nodes

High reliability. High cost of networking

8. Computer number system

1. Decimal number system

01.2.3.4.5.6.7.8.9 is composed of ten numbers

Representation () 10 or letter D

two。 Binary system

Binary is based on two numbers, only 0 and 1

Representation () 2 or letter B

3. hexadecimal

The hexadecimal base is 16.

The first ten digits are 0 to 9, followed by A.B.C.D.E and F, which represent 10.11.12.13.14 and 15, respectively.

Representation () 16 or letter H

9. Bandwidth

The unit is bits per second, denoted as bit/s. BUnip s. Bps.

10. Storage capacity

Computer storage can be measured in bits and bytes

8 bits = 1 byte, 1024 bytes = = 1Kb 1024Kb==1Mb 1024Mb==1Gb 1024Gb==1Tb

11.OSI

Address to achieve data communication, frame packaging. Frame transmission. Frame synchronization. The switch operates at the data link layer.

Physical layer: build. Maintain。 Disconnect the physical connection, define the interface and media, and realize the transmission of the bit stream.

International Organization for Standardization (ISO)

Open Systems Interconnection reference Model OSI

OSI is an open architecture that divides the network into seven layers

two。 Protocol layering

In order to reduce the complexity of network design, the protocol is designed in layers.

Service and service access point (SAP)

4. Type of service

Connection-oriented service: first establish a connection and then transfer data to ensure the reliability of data transmission

Connectionless service: does not need to establish a connection in advance, does not guarantee the reliability of message transmission

5. Service element: request. Instructions. Respond. confirm.

The meaning of 12.OSI Seven-layer reference Model

Application layer: an interface between network services and end users

Presentation layer: the representation of data, such as encryption. Compress.

Session layer: set up. Administration and Management。 Abort a session, such as a breakpoint resume.

Transport layer: define the protocol port number of data transmission, as well as flow control and error checking, to achieve the interconnection of programs, reliable and unreliable transmission.

Network layer: carries on the logical address addressing, realizes the communication between different networks, defines the IP address, chooses the best path for data transmission, and the router works in the network layer.

Data link layer: establish a logical connection. Hardware address addressing. Error check and other functions. Through MAC

13. Data unencapsulation process

In the process of transmission, the data is encapsulated from the upper layer to the lower layer, and the receiver is de-encapsulated from the bottom layer to the top layer.

XIV. Composition of the TCP / IP protocol family

Application layer: HTTP.https.FTP.TFTP.SMTP .pop3.SNMP.DNS .telnet

Transport layer: TCP.UDP

Network layer: ICMP.IGMP.IP.ARP.RARP

14.PDU (Protocol data Unit)

Transport layer segment

Network layer packet packet

Data Link layer frame frame

Physical layer bit bit

15. Equipment at the corresponding level

Application layer computer

Transport layer firewall

Network layer router

Data link layer switch

Physical layer network card

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