Tccp replay mechanism and its shortcomings
There were several types of replay mechanisms in the protocol: 1. ** Time out **: The sender will set a timer when sending data. If the receiver does not reply within the specified time, the data will be retransmitted. However, the setting of the RTO was more critical. If the time was too long, the resend would be slower, and the efficiency would be low. If the time was too short, the data packets would be resended without being lost. If the resend was frequent, it would increase network congestion, leading to more timeouts. It was a vicious cycle. Usually, the time out should be slightly longer than the round-trip time, RTO. Since the network changed frequently, the round-trip time of the message also changed. Therefore, RTO was a dynamic value. 2. ** Fast Retransmission **: Not driven by time, but driven by data. During the data transmission process, if a certain packet was not received, even if the subsequent packets were received, the acknowledgment packet would still return the serial number of the corresponding unreceived packet. After receiving the same packet three times in a row, the re-transmission mechanism would be triggered. The disadvantage of this method was that after receiving the acknowledgment packet, it was unknown which data was received and sent back. It was also impossible to determine the reception of the subsequent packets such as Seq3, Seq4, and Seq5, and it was also unknown whether the subsequent packets should be retransmitted. 3. **SACK (Selective Acknowledgment)**: Add the SACK option to the header of the protocol. The SACK records which consecutive packets were received. The sender received three identical AKs, and at the same time, it knew which packets were successfully received through SACK, so it could determine which packets to send. The disadvantage is that it requires more complicated processing, which may increase the complexity of the protocol. 4. ** Duplicated SACK (D-SACK)**: Mainly used to tell the sender which data has been received repeatedly. Its shortcomings may lead to unnecessary retransmissions, affecting performance, and introducing more acknowledgment information, which may increase network overhead. The main drawbacks of the protocol were: 1. This could cause unnecessary retransmissions, such as under the D-SACK mechanism, which could affect performance. 2. Some of the retransmissions (such as fast retransmissions) may misjudge the redundant confirmation for a long time. 3. A mechanism like SACK required more complicated processing, which increased the complexity of the protocol. 4. The re-transmission mechanism increased the network load and affected the transmission efficiency. "Choose" was equally exciting. Everyone was welcome to read it!
Tccp's fast replay mechanism
The fast replay mechanism of the protocol is a part of the protocol's congestion control mechanism. It mainly relied on the serial number and acknowledgment number in the header to decide whether to re-transmit or not. The trigger of the fast replay mechanism was related to the transmission state of the data packet. In the traditional protocol, if the sender did not receive an acknowledgment from the receiver after the timer set by the sender expired, the packet would be retransmitted (this was considered a time-out). The fast re-transmission mechanism provided a faster way to trigger the re-transmission. For example, when the receiver receives an out-of-order packet, it will immediately send a duplicate acknowledgment to the sender. If the sender received a certain number of repeated AKs in a row (usually three), it would trigger the fast replay mechanism, which quickly retransmitted the data packets that seemed to have been lost without waiting for the timer to expire. NewReno is a fast replay and recovery algorithm for the IP protocol. It is suitable for IP connections that do not support the SACK option. It is designed to improve performance in the case of multiple packet losses within a single window. In general, the fast replay mechanism helped to improve the efficiency of the transmission, reduce the delay caused by waiting for a time-out before retransmitting the data packet, and better deal with problems such as packet loss in the network. "Choose" was equally exciting. Everyone was welcome to read it!
Tccp packet loss and replay mechanism
There were two independent mechanisms for packet loss and re-transmission. One was based on the time, and the other was based on the confirmation message (Sack). Time-based Retransmission: When sending data, a timer is set. If no data acknowledgment message is received by the timer, it will trigger a corresponding time-out or a re-transmission operation based on the timer. The timer time-out is called Retransmission Time-Out (RTO). The original protocol [Ru FC 0793] used the formula: <<STMT>=<<STMT>>+<1 -<><STMT>>(constant <<STMT>> is the smoothness factor, and the recommended value is 0.8 - 0.9) to calculate the smoothed estimate of the RTO (called <STMT>). There are two threshold values in the protocol to determine how to re-transmit the same segment. R1 represents the number of times (or the waiting time) that the protocol is willing to attempt to re-transmit before sending a "negative suggestion" to the IP layer (such as re-evaluating the current IP path);R2 (greater than R1) indicates when the protocol should abandon the current connection. In a linux system, the values of R1 and R2 can be set through the application or using the system configuration variables net. ipv4. tcc-retries1 and net. ipv4. tcc-retries2. The default value of tcc-retries1 is 3, and the default value of tcc-retries2 is 15, corresponding to about 13 - 30 minutes, depending on the RTO of the specific connection. SACK-based re-transmission mechanism: If the cumulative acknowledgment of the protocol fails to return a new acknowledgment, or when the acknowledgment of the selection (SACK) contained in the acknowledgment indicates that there is an out-of-order packet, the fast re-transmission will infer that there is a packet loss and re-transmit. One of them was the NewReno Fast Retransmission and Recovery algorithm for the IP protocol. It was suitable for IP connections that did not support the SACK option. The algorithm was designed to improve performance in the case of multiple packet losses in a single window. "Choose" was equally exciting. Everyone was welcome to read it!
Tccp mass replay
The main purpose of the protocol was to prevent network packets from being dropped. The triggering methods of the retransmissions were time-out retransmissions, fast retransmissions, Sack retransmissions, and Dual Sack (D-Sack). ** 1. Overtime retransmissions result in a large number of retransmissions ** 1. ** Triggered scenario ** - When a data packet is lost or an ACK response is lost, a time-out re-transmission may be triggered. The sender sets a timer when sending data. If the sender does not receive an acknowledgment from the receiver after a specified time (RTO, Time Out Retransmission Time), the sender will resend the data packet. 2. ** Effect of RTO setting on mass retransmissions ** - The RTO could not be too long or too short. If the RTO was too long, it would take a long time to re-transmit if a packet was lost, which would be inefficient. If the RTO was too short, if the packet was blocked due to the network condition and the transmission was slow but not lost, it would also trigger re-transmission, which would cause the network to be more congested and trigger more re-transmissions. In a linux-based system, to calculate RTO, two samples were taken of the RTL (packet round-trip time). The RTL time was measured and then a smoothed RTL value was calculated by the weighed average. The fluctuation range of the RTL was also measured to avoid the situation where large fluctuations could not be found. The formula for calculating RTO is suggested in the Robuchelle Foundation's Robuchelle Foundation. RTO is calculated for the first time (let R1 be the first measurement of the RTL): RTL = R1, DevRTL = R1/2, RTO=<anno data-annotation-id ="00000000 - 4110 - 4220 - 4110 - 80111100000">[? * RTL +? * DevRTL =? * R1+? * (R1/2)]</anno>; RTO is calculated for the subsequent time (let R2 be the new measurement of the RTL): RTL = RTL +</anno>[* (RTL-RTL)=R1 +* (R2 - R1)]</anno>, DevRTL =(1 -Beta) * DevRTL +</anno>[*(RTL-RTL)]| RTT - SRTT|)=(1 -Beta) * (R1/2)+ Beta * (R2 - R1), RTO =<anno data-annotation-id ="00000000 - 4110 - 4410 - 9000 - 8000 - 90000000000"></anno></anno></anno>, RTO =<anno data-annotation-id ="000000000 - 4000 - 9000 - 9000000000000"></anno>,</anno> - If the network jam triggered a time-out, the time-out period would be doubled to prevent frequent retransmissions from worsening the network jam. That is, the next time-out period would be set to twice the current value every time the network was retransmitted. However, if the network condition continued to be poor, it might still cause a large number of retransmissions. 3. ** The relationship between the drawback of overtime retransmissions and mass retransmissions ** - The drawback of a time-out re-transmission was that the time-out period might be relatively long, and the waiting time for the re-transmission might be too long. In the case of an unstable network, this could lead to a large number of data packets accumulating and waiting to be retransmitted, resulting in a large number of retransmissions. ** 2. Rapid retransmissions result in a large number of retransmissions ** 1. ** Activation mechanism ** - Fast Retransmission no longer used time as the standard for retransmissions, but data as the standard for retransmissions. For example, when the receiver receives subsequent packets (such as Seq3, Seq4, and Seq5) but does not receive the Seq2 packet, the receiver will reply three times with an ACK2 packet. After the sender receives three packets of AK2, it will re-transmit the Seq2 packet before the timer times out. 2. ** A factor that may trigger a large number of retransmissions ** - Since the sender did not know which packets of the sender responded to the three ACK2 packets (namely Seq3, Seq4, Seq5), there might be situations where only Seq2 or all the packets were retransmitted depending on the implementation of the protocol. If all the data packets were to be retransmitted, it might cause a large number of retransmissions when there were many similar situations in the network. ** 3. The relationship between Sack and D-Sack and mass retransmissions ** 1. **Sack Retransmission ** - Sack retransmissions were selective retransmissions. It was used to solve the problem of not knowing which packets needed to be retransmitted during fast retransmissions. By adding a SACK field to the options field of the protocol, the receiver will send the sequence number range of the received data packet to the sender. This way, the sender can find the lost data packet through the SACK message and resend the data packet. If the SACK mechanism fails, for example, if the sender or receiver does not support it (SACK must be supported by both the sender and receiver. It can be enabled through the net.ipv4.tcc_Sack parameters in Linux2.4 and later), or if the SACK message transmission is wrong, it may cause the accurate selective retransmissions to be unable, which may lead to unnecessary retransmissions or even a large number of retransmissions. 2. **D - SACK** - D-Sack could let the sender know which data packets were received repeatedly. It could help determine whether the sent packet was lost or the receiver's response was lost. It could also know whether the sender's data packet was delayed or duplicated in the network. If there was a problem with the D-SACK mechanism, such as not being able to accurately determine the above situation, it would affect the sender's judgment of the network situation, which may lead to wrong retransmissions. In some cases, it may lead to a large number of retransmissions. "Choose" was equally exciting. Everyone was welcome to read it!
Tccp repeat interval
The time-based re-transmission strategy of the TCP-based re-transmission timer was to start the re-transmission interval twice the previous time. The time-out time set after the first transmission was actually 1.5 seconds. After that, the time-out time was doubled with each re-transmission until 64 seconds. The exponential back-off algorithm was used. There were a total of 12 retransmissions, and it took about 9 minutes to give up. This time was immutable in the current implementation of the protocol, but the administrator of Solar 2.2 allowed the administrator to change this time (the variable of the protocol_ip_abort_interval). The default value was two minutes, instead of the most commonly used 9 minutes. "Choose" was equally exciting. Everyone was welcome to read it!
NBA replay, full video replay
There were replays of the Blazers vs. Timberwolves on November 14, 2024, and the Lakers vs. Grizzlies on November 14, 2024. In addition, there was a replay of the first round of the playoffs between the Los Angeles Clippers and the Grizzlies on April 17, 2023. Harry Potter and the Goblet of Fire was not enough. Everyone, please click to read the novel!
Proficiency mechanism
The proficiency mechanism referred to the increase in the proficiency level of the character through performance and completion of specific tasks in the game. Different games had different proficiency mechanisms. For example, League of Legends and Naruto both had proficiency bonus mechanisms. In League of Legends Mobile, players could obtain proficiency and hero points by obtaining an S-rank evaluation, an A-rank evaluation, and victory in the qualifying matches. In Naruto Mobile Games, players needed to accumulate a certain amount of proficiency points to increase their proficiency level. Other games such as Dungeon Fighter Online and Scarlet Scar Night Ritual had a similar proficiency system. Players could increase their proficiency levels by completing missions and clearing dungeons. In general, the proficiency mechanism could help players improve their character's skills and strength. At the same time, it also provided players with rich rewards and advantages.
The mechanism of isoniazid
The mechanism of action of isoniazid was not completely clear, but the following conclusions were made: isoniazid was a synthetic antiseptic that had a specific effect on the bacteria. Its effect may be carried out in a variety of ways, including hindering the synthesis of Phospholiptides and mycolic acid in the cell wall of the M. tubers, causing the bacteria to lose acid resistance and proliferate and die. In addition, isoniazid can also be oxided into isonicotinic acid in the bacteria, interfering with the growth of the bacteria. It could also combine with the NAD glucose protector to affect the synthesis of DNA, and combine with the copper ions required by the fungus to make the bacteria lose its activity and play an antiseptic role. In short, isoniazid has a disinfecting effect on M. tube-like bacteria through a variety of pathways.
Synaptic mechanism
The formation and regulation mechanism of the Synapse is an important research topic in the field of neuroscience. Some information about the mechanism of the Synapse. First of all, the Synapse was the connection point for information transmission between neurons, and it was highly dynamic. The formation and regulation of the Synapse involves the interaction of multiple protein and molecules. Among them, the protein psd-95 and SynGAP in the post-Synaptic Dense Zone (PSD) could undergo liquid-liquid separation at high concentration, which provided a possible answer to the formation of the Synapse. In addition, Synaptic attachment molecules such as Latrophilin-3 (Lphn3) play an important role in the establishment of the Synapse. It can bind to the tenurin and FLVRT-like attachment molecules in the presynaptic membrane. In addition, the formation and regulation of the Synapse also involved the control of the Trans-Synaptic Complex between the presynaptic membrane and the Post-Synaptic membrane. However, there were still many questions about the specific mechanism of the neural network, and further research was needed to answer them.
The mechanism of love
The mechanism of love was a complicated process that involved many biological and social factors. In terms of biology: - Brain chemical reaction: The neurotransmitter in the brain, such as Dopamine, Norepinephrin, and Pitocin, is the chemical basis for love. When two people look at each other, the brain will secrete phelethylamin, producing a feeling of "electricity" and falling in love. It will also bring about physiological reactions such as accelerated heartbeat, red face, dilated pupils, and so on. It will also make men and women in love feel confident. As love progressed, physical contact increased, and the brain synthesized norepinephrin, causing blood vessels to contract, causing blood pressure, heart rate, and blood sugar to rise at the same time. Dopamine in the brain was responsible for transmitting information about excitement and pleasure. It was related to the addiction mechanism and made people crave the joy of love. The secretion of endorphins would increase exponentially during the development of a relationship, giving people a sense of euphoria, accomplishment, and vitality. After the climax, the Dopamine faded, and endorphins made people feel warm and satisfied. The vasopressin in the brain would strengthen the love between lovers and make them more loyal. - * - Sight and Sound: Certain attributes of facial features and tone of voice can enhance the emotional connection between men and women. In terms of society, social factors such as culture, family, circle of friends, and education also affect the possibility of love between men and women.
The star of the clock mechanism
I'm not sure which novel you're referring to. It's called the star of the clock mechanism. Can you tell me its name or provide more context? This way, I can better answer your questions.