Test Points Introduction
The OSI seven-layer reference model divides the necessary functions in the communication protocol into seven layers. Through these layers, more complex network protocols can be simplified. By using each layer independently, even if some layers in the system change, it will not affect the entire system.
The seven-layer model of the front-end professional course - related topics and analytical content can be viewed by clicking on the link at the end of the article!
1. Exam questions
1. Which of the following has nothing to do with the connection-oriented service at the transport layer?
A. There is a coordination process before transmitting data between the two ends
. B. Allocating relevant resources between the two ends
. C. Establishing a transmission path between the two ends
. D. Providing communication between the two ends. In-sequence reliable delivery service
The correct answer is C. First of all, it must be clear that connection-oriented services mean that connection messages are sent before and after data transmission, commonly known as handshakes and waves.
This coordination process refers to the handshake process. After the handshake process, relevant resources are allocated for better control. Whether it is TCP or UDP, they all need to establish a transmission path between both ends...
2. The transport layer can identify different applications through ( )
A. Physical address
B. Port number
C. IP address
D. Logical address
The correct answer is B. The physical address is the MAC address, which records the location of the host on the earth. The port number represents the entry point of the application process. Common port numbers are listed below...
3. The data link layer uses SR to transmit data. The sender has sent data frames numbered 0 to 3, and has now received the confirmation of frame 1. However, frames 0 and 2 have timed out in sequence, and they need to be retransmitted at this time. The number of frames is
A.1
B.2
C.3
D.4
The correct answer is B SR (select repeat) select retransmission protocol. If something went wrong, I re-shipped and received confirmation No. 1...
2. Examination articles
1. [VIP recruitment] Resume guidance for product managers (1)
1. Basic concepts and principles of
OSI OSI is the abbreviation of Open System Interconnect, which means open system interconnection. The division of each layer follows the following principles:
(1) Each network node in the same layer has the same hierarchical structure and has the same function.
(2) Communication between adjacent layers within the same node occurs through interfaces.
(3) Each layer in the seven-layer structure uses the services provided by the next layer and provides services to the layer above it...
2. [Campus Recruitment VIP] Network protocols that the front-end must understand.
TCP/IP is a transport layer protocol, which is a collective name for various protocols related to the Internet. It mainly solves how data is transmitted in the network; HTTP is an application layer protocol, which mainly solves how to transmit data in the network. Packaging data.
Socket is an encapsulation of the TCP/IP protocol. Socket itself is not a protocol, but a calling interface (API). Through Socket, we can use the TCP/IP protocol...
3. [Campus Recruitment VIP] Front-end network basics - Transport layer UDP protocol
UDP (User Dategram Protocol) is the User Datagram Protocol, which is also a transport layer protocol.
We need to know that data is divided into important data and unimportant data. For example, if you send an email or download a file, these are important data. If there is a little less, the file may report an error and cannot be opened, so for this data, we What matters is completeness and correctness.
But for example, if you watch online live broadcasts, make IP calls, or play online games, which require high real-time data and fast data transmission speed, we don’t care much about the integrity of the data. For example, when you are watching an online live broadcast, there is a sudden freeze. In fact, it does not affect the overall live broadcast experience at all. Or when you are playing a game, you don't care whether the data is complete at all, as long as the game control is smooth and the feedback is timely...
3. Test point video
Characteristics, test points and career development of front-end school recruitment
Front-end is currently the most cost-effective position in IT school recruitment. It does not require high majors, the test points are less difficult, and the demand is large. During school recruitment, there are first- and second-tier companies and ordinary companies, and the corresponding school recruitment requirements, wages and career development are all different...
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seven-layer model of the front-end professional course - mobile link
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