Summary of basic concepts of computer network

To master the knowledge and skills of computer network is a required course for every professional student. The following is the information of the computer network which oneself organizes. Now share with you.

The classification and main functions of computer network are discussed.

A: 1. By Network Transmission technology classification: Broadcast network, point-to-point network.
2. By network Coverage Scale classification: LAN, man, WAN.
3. Classification by topological structure: bus-type network, ring-type network, star-type network.

The main functions are:
Resource sharing
Information transmission and centralized processing
Balanced load and distribution processing
Integrated Information Services


What is channel bandwidth and channel capacity? What's the relationship between them?

A: Channel bandwidth refers to the frequency range in which a channel can transmit a signal without losing its true meaning.
Channel capacity refers to the maximum amount of signal that a channel can transmit per unit of time, signaling the transmission capability of a channel.

Proportional relationship.


What are the advantages of packet switching technology compared to circuit switching?

For:



This paper briefly describes the definition, classification and main functions of LAN.

A: The definition: LAN is a limited geographical coverage of multiple computers, through the transmission media connected to the communication network, through the perfect network software to achieve communication between computers and resource sharing.

Category: By media access control classification: Shared LAN, switched LAN
By means of communication: Peer network, client/server network, diskless Workstation network

Main functions: Resource sharing, data communication, improve the reliability of computer system, easy to distribute processing.



What are the characteristics of the bus type, ring type and star topology of LAN?

A: Bus type: The biggest advantage is the low price, the user site flexible network, while one site failure will not affect other sites. The disadvantage is that it is not easy to extend, the fault tolerance is poor, and the interruption on the bus affects the whole network.

Ring Type: A single workstation failure can paralyze the entire network. The more workstations, the longer the response time. Inflexible is not easy to expand.

Star: The cable problem only affects two nodes. Failure of a central node (such as a hub) will cause the network to become paralyzed. Star-shaped easy to move, easy to connect with other networks.



Describe the characteristics and working principles of the Internet.

A: Features: 1. Flexible and diverse network access methods
2. Using client/server program mode
3. Integration of multiple information technologies
4 Low Fees
5. Resource-rich
6. Rich Information service function and friendly user interface

How it works: 1. Packet switching
2. client/server Programs


Some people say that the IP address equals the domain name, is this saying right? Why?

Answer: No.
IP address provides an all-network unified address format, under the unified management, the address assignment, to ensure that an address corresponds to a host. is represented by a binary number of 32 bits.

Domain name is a type of host naming mechanism, that is, to each host a regular name, the host name relative to the IP address is a more advanced form of the address. Consists of a hostname, an organization name, a network name, and a top-level domain name.



What parts of the computer network are made up of? What is the role of each part?

A: Resource subnets and communication subnets

Resource subnets provide resources such as hardware, software, and data needed for resource sharing, providing access to computer networks and processing data.

The communication sub-network completes the data transmission, the Exchange and the communication control, provides the service for the computer network communication function.




OSI/RM is divided into which layers? Provides a brief description of the functions of each layer.

A: Physical layer: Determine the physical characteristics of the transmission media; transmit binary bits; define the transmission mode (simplex, half duplex, full duplex)

Data Link layer: Framing, physical address addressing, flow control, error control, access control.

Network layer: Logical address addressing, route selection, flow control, congestion control.

Transport layer: interface and bridge of communication subnet and resource subnet for reliable end-to-end transmission.

Session layer: Establish, maintain, end the session connection function.

Presentation layer: The representation used for information. such as data compression, data encryption and so on.

Application layer: Provides a variety of high-level protocols for network users and applications.



How many layers does the TCP/IP protocol model consist of? What are the functions of each layer? What protocol does each layer contain?

A: The network interface layer: Provides flexibility for the network to accommodate a variety of network types. Enables TCP/IP to run on top of any network.

Internetwork: Handles packets from the transport layer, routing, and transferring packets from the source host to the target host. "IP ICMP IGMP ARP RARP"


Transport layer: Responsible for end-to-end communication between hosts. "TCP UDP"

Application layer: Provide network services, such as file transfer. "FTP DNS HTTP TELNET"


11. What are the common network devices? What is the difference between routers and switches?

A: The router works at the network layer. There are routing, flow control, and filtering capabilities. When two networks are interconnected, you must use a router.

The switch works at the data link layer. It also has the function of bridge and router. Combine software addressing with hardware switching.

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Summary of basic concepts of computer network