TCP retransmission
The mechanism for ensuring the reliable transmission of data mainly includes the following aspects:
** 1. Principle and Core Elements of Retransmission **
1. ** Confirm mechanism **
- In the case of a packet, the receiver would return an acknowledgment message (ACK) to inform the sender that it had successfully received the data. The sender waited for an acknowledgment after sending the data packet. If the packet was not received within a specified time, it would be considered as a lost data packet and trigger the replay mechanism.
2. ** Swipe the window **
- The sliding window mechanism was used by the protocol to achieve flow control and congestion control. The sender's window size determines the number of packets that can be sent. When the receiver returns an acknowledgment, the sender's window will slide, and the sender can continue to send new packets. If there are unconfirmed packets, the window will stop sliding until the sender receives an acknowledgment or triggers a replay mechanism.
3. ** Sequence Number **
- Each packet was assigned an independent sequence number to ensure orderly transmission. The receiver sorts the data packets according to the serial numbers. If the serial numbers are not continuous, it means that there is a packet loss and will request the sender to resend.
4. ** Retransmission timer **
- The sender of the protocol monitors the packets that have been sent but have not received an acknowledgment. When the timer expired, the sender would assume that the corresponding data packet was lost and trigger the replay mechanism. In order to adapt to different network environments, the self-adapting timer adjustment strategy was used to adjust the time-out threshold.
** 2. Retransmission trigger condition **
1. ** Time out for re-transmission **
- When the sender sends the data packet, it starts the re-transmission timer and waits for the acknowledgment. If the sender did not receive an acknowledgment before the timer expired, the sender would assume that the packet was lost and trigger a time-out. This could happen when a packet is lost or an acknowledgment is lost. The setting of the Retransmission Time-Out (RTO) was critical. If the RTO was too large, the sender would have to wait for a long time to discover the loss of the message segment, which would be inefficient. If the RTO was too small, some message segments with large delays might be mistaken as lost, causing unnecessary retransmissions to waste network resources. Therefore, the value of RTO was not fixed. It was slightly larger than the connection round-trip time (RTL, which was the time from sending data to receiving the return acknowledgment packet). In the linux-based system, to calculate RTO, it samples the RTL. The smoothed RTL value is calculated by the weighed average. At the same time, the fluctuation range of the RTL is also measured. The calculation formula is: when RTO is calculated for the first time, if R1 is the first measured RTL, then RTL = R1, DevRTL = R1/2, RTO= 0.(\mu * SRTT+\delta * DevRTT=\mu * R1+\delta * (R1/2)\); In the subsequent calculation of RTO, if R2 is the newly measured RTL, then STTL = STTL +<
[Random Retransmission]
Selective Repeat Protocol。 " Choose " was equally exciting. Everyone was welcome to read it!
Quick Retransmission and Quick Recovery
Fast retransmissions and fast recovery were two concepts in network communication. Fast Retransmission meant that the receiver would immediately send out a repeat acknowledgment after receiving a message segment that was out of order, instead of waiting for a complete message segment to be received before sending out a confirmation. As for fast recovery, it was after a fast replay. In order to avoid network congestion, the sender did not directly enter the slow start phase. Instead, it used a gentler method to adjust the size of the sending window so that the data transmission could quickly recover to normal. These two concepts were mainly used to improve network transmission efficiency and deal with network congestion. " Choose " was equally exciting. Everyone was welcome to read it!
Reason for selecting the Retransmission Protocol-Receiving window
If the size of the reception window in the transmission protocol is greater than 1. The main reasons for the existence of the receiving window were as follows: ** 1. Flow control ** 1. ** Increase reception efficiency ** - The receive window can control the range of data frames that can be received. It allows the receiver to receive multiple data frames within a certain range. In this way, the receiver can avoid frequently interacting with the sender to confirm each data frame one by one, thereby improving the efficiency of receiving data. For example, if the size of the receiving window is three, under suitable network conditions, the receiver can receive and process three data frames at once without waiting for the sender's permission to send each data frame. 2. ** Adapt to the changes in the network environment ** - In a network environment, the data transmission speed might fluctuate. The size of the receiving window can be adjusted according to the network congestion. If the network condition was good, the receiving window could be expanded appropriately to allow more data frames to enter the receiving range and improve the data receiving speed. If the network was congested or unstable, the receiving window could be reduced to avoid receiving too many data frames, resulting in data loss or insufficient processing. ** 2. Data processing ** 1. ** Receiving and processing in an orderly manner ** - The receiving window helps the receiver to receive and process the data frames in an orderly manner. Although the size of the transmit window and the receive window in the selective replay protocol were both greater than 1, the receive window could ensure that the received data frames were within the expected sequence range. If the serial number of the received data frame fell outside the receiving window, the receiver could discard it all. This could ensure that the receiver only processed the data frames that met the requirements, which was convenient for the orderly integration and subsequent processing of the data. 2. ** Cooperate with error handling and replay ** - When a data frame is lost or has an error during transmission, the existence of the receiving window is convenient to cooperate with the re-transmission mechanism of the selective re-transmission protocol. The receiver can feedback which data frames need to be retransmitted to the sender according to the data frames received within the receiving window. Since the size of the receiving window is larger than 1, the receiver can more flexibly deal with various error situations that may occur, such as partial data frame loss or data frame disorder. " Choose " was equally exciting. Everyone was welcome to read it!
Choose the size of the reception window of the Retransmission protocol.
By default, the size of the receive window is equal to the size of the send window in the selective replay protocol (SSR), but no information about the specific size was found. In the example where the frame sequence number is represented by 3 bits, the principle that the sending window meets is that the size of the sending window is equal to the receiving window, but the specific size of the receiving window is not specified. "Choose" was equally exciting. Everyone was welcome to read it!
What were the competing technologies with TCP/IP in the novel?
In the novel, some potential competing technologies to TCP/IP might have been satellite-based communication systems or advanced wireless networks.
What makes a cartoon about the TCP layer funny?
It could be the way it simplifies complex TCP concepts into easy-to-understand and humorous visuals.
What are the main differences between TCP and UDP in a comic representation?
In a comic, TCP is often shown as more reliable and orderly, like a well-organized delivery service. UDP, on the other hand, is depicted as faster but less reliable, like a speedy messenger who might sometimes make mistakes.
What are the recruitment requirements for the host assistant? How to fill them in?
The following are some common recruitment requirements and filling methods for streamer assistants: ** I. Recruitment Requirements ** 1. ** Professional background ** - If the hiring party has requirements for majors, such as media, art, and other related majors are preferred. When filling in the application information, if you have a relevant professional background, you must clearly write the name of your major, the school you graduated from, and the courses related to media or art, such as communication principles, performance foundation, etc. - If you don't have a relevant professional background, but have relevant self-study experience or online course learning experience, you should also briefly explain, for example, you have participated in online training courses related to the media industry, learned video production, live broadcast planning, etc. 2. ** Understanding of the live streaming industry ** - Recruitors might want job applicants to have some understanding of live streaming platforms and tools. When filling in the form, you can list the live streaming platforms you are familiar with (such as TikTok, Douyu, etc.), and describe the live streaming tools you are familiar with, such as OBS (used for live streaming and picture switching), as well as your relevant experience on these platforms and tools. For example, you have used OBOSS for simple live streaming tests or video recording. - If you are an in-depth user of a live streaming platform, you can mention the type of live streaming you follow, the host, and your understanding of the live streaming trend of the platform. For example, you can understand the different audience characteristics of entertainment live streaming and e-commerce live streaming on TikTok. 3. ** Communication skills and teamwork spirit ** - When filling out the application form, you can give examples of your communication skills, such as how to effectively communicate with team members to complete projects in your past work or study, or how to interact well with different people in social activities. - As for teamwork, you can talk about the team projects you have participated in, your role in the team, and how to cooperate with the team members to overcome difficulties. For example, you have participated in campus club activities, and you are responsible for coordinating materials and personnel arrangements with different departments. 4. ** Personal traits ** - Recruitors may require applicants to be careful, patient, and have strong adaptability. When filling in the form, you can show your carefulness through examples, such as being able to accurately enter data in data processing work, and prove your patience with past experience, just like patiently answering customer service questions in customer service practice. - The ability to adapt could be demonstrated by describing how one dealt with unexpected situations. For example, if one encountered equipment failure during an organized activity, one could quickly find a solution to ensure that the activity continued. 5. ** Work experience related ** - If you have a streamer assistant or relevant work experience, it will be preferred. Experienced applicants were required to describe their job details, including assisting the streamer in preparing for the live broadcast (such as equipment inspection, scene layout, and other specific work content and results), supporting the live broadcast process (how to manage the chat room, respond to emergencies, etc.), as well as sorting out the content and collecting feedback after the live broadcast. - If you don't have any relevant work experience, you can mention some similar experiences, such as participating in behind-the-scenes assistance work for video shooting, being responsible for props preparation and on-site order maintenance, etc., emphasizing that these experiences are in line with the requirements of the streamer assistant. ** II. Please fill in the notes ** 1. clear and accurate - When filling in the recruitment application form or resume, the content related to the recruitment conditions should be clearly stated to avoid vague descriptions. For example, when describing your familiarity with live streaming platforms, don't just say that you know some live streaming platforms. Instead, you have to specifically mention the name of the platform, its functions, and your depth of use. 2. emphasize - According to the importance of the recruitment conditions, the order of filling in the contents should be arranged reasonably, and the contents related to the key recruitment conditions should be placed in a prominent position. For example, if the recruitment emphasized understanding of the live streaming industry, they would put their advantages in this area (such as mastery of live streaming platforms and tools, understanding of live streaming trends, etc.) in front of them. 3. concise and clear - He avoided long and complicated statements and used concise language to express key information. For example, when describing work experience or project experience, focus on the key links and results to describe, and don't involve too many irrelevant details. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
TCP retransmission
The mechanism for ensuring the reliable transmission of data mainly includes the following aspects: ** 1. Principle and Core Elements of Retransmission ** 1. ** Confirm mechanism ** - In the case of a packet, the receiver would return an acknowledgment message (ACK) to inform the sender that it had successfully received the data. The sender waited for an acknowledgment after sending the data packet. If the packet was not received within a specified time, it would be considered as a lost data packet and trigger the replay mechanism. 2. ** Swipe the window ** - The sliding window mechanism was used by the protocol to achieve flow control and congestion control. The sender's window size determines the number of packets that can be sent. When the receiver returns an acknowledgment, the sender's window will slide, and the sender can continue to send new packets. If there are unconfirmed packets, the window will stop sliding until the sender receives an acknowledgment or triggers a replay mechanism. 3. ** Sequence Number ** - Each packet was assigned an independent sequence number to ensure orderly transmission. The receiver sorts the data packets according to the serial numbers. If the serial numbers are not continuous, it means that there is a packet loss and will request the sender to resend. 4. ** Retransmission timer ** - The sender of the protocol monitors the packets that have been sent but have not received an acknowledgment. When the timer expired, the sender would assume that the corresponding data packet was lost and trigger the replay mechanism. In order to adapt to different network environments, the self-adapting timer adjustment strategy was used to adjust the time-out threshold. ** 2. Retransmission trigger condition ** 1. ** Time out for re-transmission ** - When the sender sends the data packet, it starts the re-transmission timer and waits for the acknowledgment. If the sender did not receive an acknowledgment before the timer expired, the sender would assume that the packet was lost and trigger a time-out. This could happen when a packet is lost or an acknowledgment is lost. The setting of the Retransmission Time-Out (RTO) was critical. If the RTO was too large, the sender would have to wait for a long time to discover the loss of the message segment, which would be inefficient. If the RTO was too small, some message segments with large delays might be mistaken as lost, causing unnecessary retransmissions to waste network resources. Therefore, the value of RTO was not fixed. It was slightly larger than the connection round-trip time (RTL, which was the time from sending data to receiving the return acknowledgment packet). In the linux-based system, to calculate RTO, it samples the RTL. The smoothed RTL value is calculated by the weighed average. At the same time, the fluctuation range of the RTL is also measured. The calculation formula is: when RTO is calculated for the first time, if R1 is the first measured RTL, then RTL = R1, DevRTL = R1/2, RTO= 0.(\mu * SRTT+\delta * DevRTT=\mu * R1+\delta * (R1/2)\); In the subsequent calculation of RTO, if R2 is the newly measured RTL, then STTL = STTL +<<alpha * (RTL-STTL)>=R1+<alpha * (R2 - R1)>, DevRTL =(1 -<beta>)* DevRTL +<beta *>(<beta>)| RTT - SRTT|)=(1 -beta) * (R1/2)+ beta * (R2 - R1), RTO=(mu * SKMT + Delta * Dev MTMT)(in linux (alpha = 0.125),(beta = 0.25),(mu =1),(Delta = 4). Moreover, in the case of a repeat transmission, RTO was not calculated using the above formula, but using a method called "exponential backoff." When the 3rd repeated ACK is received, ssrefresh is set to the current congestion window cwn, and when the next ACK confirming new data arrives, cwn is set. 2. ** Rapid Retransmission ** - When the receiver receives three consecutive acknowledgment packets with the same serial number, the sender will think that the corresponding packet has been lost and trigger a fast replay. This is a replay strategy to improve the performance of the protocol. In addition, there were also SACK and Repeat SACK methods. The protocol used the sequence number and acknowledgment number in the header to decide whether to re-transmit or not to prevent the network packet from being dropped. "Choose" was equally exciting. Everyone was welcome to read it!
We made mooncakes
We made mooncakes. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>