Ipsec-esp protocol
An architecture that was designed to provide security services in a hybrid application of both the IPv4 and IPv6 networks. It provides confidentiality and integrity by encryption of the data to be protected and placing the encrypted data in its data portion. It uses a symmetrical key encryption algorithm to provide data integrity verification, data source verification, and anti-replay attack services. Depending on the user's security requirements, it can be used to encrypted the transmission layer (such as IP, IP, IGMP), or it can be used to encrypted the entire IP packet. Encapsulated protected data was necessary to provide confidentiality for the entire raw data report. The EP header can be placed after the IP header, before the upper layer protocol header (in the transport layer mode), or before the encapsulated IP header (in the tunnel mode). The protocol value assigned by Ivana to the EP header is 50. The protocol header before the EP header will contain the value 50 in the "next head" field of the IP version 6 or the "protocol" field of the IP version 4. The ESP contains a non-encrypted protocol header followed by encrypted data. The encrypted data covers the protected ESP header field and protected user data. The user data can be the entire IP datagrams or the upper layer protocol frame of the IP (for example, the protocol of a protocol such as a protocol or a protocol such as a protocol. In addition, the set of services provided by the EP is determined by the options selected and the arrangement of the implementation when the secure connection (Sa) is established. The confidentiality option is independent of other services, but using the confidentiality service without the integrity/authentication service (in the EP or in AH alone) may cause the transmission to be subject to some form of attack and destroy the confidentiality service. Data source verification and integrity of the non-connection are related services, provided to the user in combination with confidentiality (option). The anti-replay service can only be selected when the data source verification is selected, and the receiver can decide the choice of the anti-replay service alone. The novel "Dream of Silk Fate" is equally exciting. Everyone is welcome to click and read it!
Which layer does the esp protocol belong to?
EP (Encapsulated Security Payload protocol) was a network layer protocol that was encapsulated above the IP protocol. The novel "Dream of Silk Fate" is equally exciting. Everyone is welcome to click and read it!
Which layer does the esp protocol belong to
The EP protocol was a network layer protocol, and it was packaged above the IP protocol. The novel " Dream of Silk Fate " is equally exciting. Everyone is welcome to click and read it!
What security services does the esp protocol provide?
The EP protocol provides security services such as data integrity verification, data source verification, anti-replay attack services, confidentiality, data source authentication, integrity of the connection, anti-replay services (a form of partial sequence integrity), and limited information flow confidentiality. In addition, it also provided data stream confidentiality services in tunnel mode. The novel "Dream of Silk Fate" is equally exciting. Everyone is welcome to click and read it!
Principles of gbt protocol and sl protocol
GGN (N-step Backward Agreement): - The sender's theory: - The sender uses the pipeline technology to allow multiple packets to be sent without waiting for acknowledgment, but it is limited by the number of unacknowledged packets in the pipeline cannot exceed the maximum number N. When the upper layer calls the send function (rdt_send ()), the sender first checks whether the send window is full (i.e., whether there are N sent but unacknowledged packets). If the window is not full, a packet is generated and sent, and the relevant variables are updated at the same time. If the window is full, the sender can choose to return the data to the upper layer (in reality, it is more likely to buffer the data or use a synchronization mechanism. The upper layer is only allowed to call the send function when the window is full). - The receiver acknowledges the packet with the sequence number n in a cumulative manner, indicating that the receiver has correctly received all the packets before and including the sequence number n. - If there is a time out (the timer is used to detect the loss of data or acknowledgment packets), the sender will resend all the packets that have been sent but not acknowledged. - Principle of the receiver: The receiver receives the packets and uses the cumulative confirmation method to feedback the situation of the correctly received packets to the sender. PR (select the replay protocol): - The sender and receiver had their own windows. The sender sends the packet without knowing the position of the receiver's window, and the receiver receives the packet without knowing the position of the sender's window. The two windows are not synchronized. - The problem was that if the size of the sequence number space and the window size did not meet a certain condition (for example, a scenario where the size of the sequence number space was 4 and the window size was 6 would be problematic), the receiver might not be able to distinguish between different situations. For example, the receiver might mistake the retransmitted packet as a new packet and receive it incorrectly. Different from the GGN protocol, the ACK (n) and TimeOut (n) in the GGN protocol would cause a lot of resources to be retransmitted, resulting in a waste of resources. The SSR protocol was more selective in dealing with situations such as retransmissions. "Choose" was equally exciting. Everyone was welcome to read it!
ESP system
The electronic stability Program was an electronic stability system for cars. It was a brand-new generation of active safety control system that could significantly improve the vehicle's handling stability under various extreme conditions. Its function was to monitor the driving state of the vehicle. By monitoring the parameters such as the steering direction, wheel speed, sideslip, and lateral acceleration of the vehicle, it could perform dynamic stability control on the vehicle to ensure that the vehicle remained stable in an emergency and prevent the vehicle from deviated from the ideal trajectory. The ESP system can automatically apply braking force to one or more wheels to ensure that the vehicle is running on the normal lane and can also automatically correct the vehicle's trajectory. The EP system was not an independent system, but was built on the basis of the Anti-lock Braking System (ABS) and the Acceleration Slip Control System (ASR). It was composed of sensors (such as steering sensor, wheel sensor, sideslip sensor, and lateral acceleration sensor), an ESP computer executor, and an ESP lamp on the dashboard. The principle was to control the stability of the vehicle through direct yawing moment, which meant that the braking force and driving force of the four tires were independently controlled to generate additional yawing moment, so that the vehicle could track the ideal control target according to the driver's driving intention under various working conditions. ESPs could be divided into four or four channel systems, two channel systems, and three channel systems. They had the characteristics of active safety, real-time response, multi-functionality, individual adaptation, and improved control performance. When the car is driving, when there is understeer, oversteer, or slipping on the road, the ESP system can effectively prevent the car from losing control and greatly improve the safety of the car. However, in some special situations, such as off-road driving, driving through sand and snow, sinking into quagmire, or drifting and other extreme driving, the ESP system would limit the engine speed. At this time, it was necessary to turn it off to increase the speed of the engine wheels. Most cars would have an EP system, some cars would have it as standard equipment, and some would have it as an option. It was difficult to install the EP system. It was not recommended to install it later because it was composed of a series of sensors and needed to go through a series of tests and debugs. Even if the later installation was successful, it could not guarantee that it would work at a critical time and might even bring potential risks. The novel "Dream of Silk Fate" is equally exciting. Everyone is welcome to click and read it!
Continuous arq protocol and sliding window protocol
In the continuous ARQ protocol, the sender maintained a sending window of a certain size, and the packets within the window could be sent continuously without waiting for the other party's acknowledgment. The sender would slide the sending window forward by one packet every time it received an acknowledgment. The receiver usually uses the method of accumulating acknowledgement, that is, after receiving several packets, it sends an acknowledgement to the last packet that arrives in order, indicating that all the packets up to this packet have been received correctly. However, this method has shortcomings. For example, when the middle packet is lost, the sender cannot know the situation of the subsequent packets, and may need to re-transmit more packets. The sliding window protocol involves a sending window and a receiving window. The transmit window is the range of sequence numbers of the frames that have been sent but have not been acknowledged, and the receive window is the range of sequence numbers of the frames that are expected to be received. When the default window size is 1, you can operate according to the specific sending process. The sliding window protocol could improve the channel utilization and was a reliable transmission mechanism for data communication. The continuous ARQ protocol can be seen as a specific application form of the sliding window protocol under certain conditions (such as the cumulative acknowledgment method). They are all protocol mechanisms that exist to achieve effective and reliable data transmission in the network. "Choose" was equally exciting. Everyone was welcome to read it!
The difference between AH protocol and EP protocol
The difference between the gmn protocol and the sl protocol
Both GGN (Fallback N-frame protocol) and SSR (Random Repeat protocol) were sliding window protocol under the reliable data transmission protocol in computer networks. There were the following differences between the two: 1. ** Receiving window size ** - ** GGN protocol **: Receiving window <br>(W = 1 <br>), which means that the receiver can only receive the data packets that arrive correctly in order. If an error occurs in a data packet, it will cause the subsequent packets to be discarded because they cannot be received in order by the receiver, even if these packets are not error-free and out of order. - ** PR protocol **: If the receiving window size is greater than 1, the receiver can receive packets out of order. 2. ** Confirm Method ** - ** GGN protocol **: uses cumulative acknowledgment. The receiver acknowledges the last frame of a group of frames that arrive in order, indicating that all the frames before this frame have been received. For example, if the sender sends four frames 1, 2, 3, and 4, and the receiver acknowledges frame 4, it means that the four frames 1, 2, 3, and 4 have been received. The previous frames 1, 2, and 3 are no longer separately acknowledged. - ** PR protocol **: Each packet has a separate confirmation mechanism. The receiver can confirm each correctly received packet separately, and the sender can selectively re-transmit the incorrectly received packet according to the confirmation information of the receiver. 3. ** Retransmission mechanism ** - ** GGN protocol **: When the sender receives an acknowledgment for a frame, the sending window will be moved forward. If there is a packet loss or a long delay (such as a timer exceeding), the sender needs to resend all the packets that have been sent but have not been acknowledged. For example, if the sender sends six frames, frame 1, 2, 3, 4, 5, and 6, the receiver will confirm frame 3, and the sender will think that frame 1, 2, and 3 have been sent correctly. If there is a problem later, frame 4, 5, and 6 will need to be retransmitted. - ** PR protocol **: The sender only re-sends the packet that the receiver did not receive correctly, instead of re-transmitting all the sent frames after the acknowledgment frame like the GGN protocol. 4. ** Resource utilization and wastage ** - ** GGN protocol **: Due to the method of accumulating acknowledgement and returning N frames of retransmissions, the error of one packet may lead to the retransmissions of multiple packets, even if these packets themselves are error-free. This causes a waste of resources to a certain extent, especially when the window is large and the bit error rate is high. A large number of unnecessary packets may be frequently retransmitted. - ** SP protocol **: Compared to the GGN protocol, it is more resource-saving because it only reforwards the packets that the receiver did not receive correctly, avoiding unnecessary packet retransmissions and thus improving the channel utilization. However, there were some problems with the SSR protocol. For example, the receiver and sender windows were not synchronized, which could cause errors. "Choose" was equally exciting. Everyone was welcome to read it!
Is the select replay protocol a sliding window protocol?
Yes, the selective replay protocol was based on the sliding window flow control technology. It was a sliding window protocol. " Choose " was equally exciting. Everyone was welcome to read it!
ARP protocol
The Address Resolution Protocol was a network layer protocol. It was between the data link layer and the network layer. It played a vital role in network communication, just like the address translator in the network. Its main function was to convert the IP address of the network layer to the data link layer's IP address. This was because in network communication, although the IP address was used to identify the host at the network layer, it was forwarded through the IP address at the data link layer (such as the ether network). The host or the layer 3 network device would maintain an ARP-table to store the IP address and the MAC-address map. The ARP-table entries included dynamic and static ARP-table entries. The working process was as follows: When host A needed to communicate with host B, it first determined the forwarded IP address according to the route table, and then checked the local ARP-buffer. If there was no matching address, it would broadcast an ARP-request frame in the network. All hosts in the same broadcast domain will receive this request. For example, after receiving the request, host C will find that the destination address is not its own, and then it will buffer the address of host A into its own ARP-table, and then discard the packet. After receiving the request, host B will find that the destination address is its own, and then it will buffer the address of host A and give a response. Then it will package its own address in the response ARP-packet and send it to host A. After receiving the response, host A will update its own ARP-buffer. There were two ways to obtain the ARPs: static and dynamic. The static acquisition was equivalent to manually configuration of the address map in the ARP-table. If the physical address changed, it would need to be manually changed, which was more troublesome. The dynamic acquisition was to obtain and update the address map by the host through the protocol, which was relatively convenient. In addition, there was also a free ARP-type message that was used to detect whether there was an IP address conflict. It would send a broadcast message with the same source and destination IP. Under normal circumstances, it was not expected to receive a response. If a response was received, it meant that there was an address conflict. In the Windows system, there were related ARP-commands. For example, ARP-a could check the ARP-buffer table, and ARP-d could delete the ARP-buffer table. However, due to network communication requirements, the buffer table might be regenerated immediately. In November 1982, the Internet Engineering Task Force (IetF) published the Internet Packet Packet Interface Problem (ARPG) 826. It was an indispensable protocol for the Internet Packet Interface Version 4, which was the most widely used version of the Internet protocol.(The Internet Packet Interface Version 6 was still in the early stages of deployment.) The role of the ARP-protocol in the car's ether network was the same as that of the traditional ether network. "Choose" was equally exciting. Everyone was welcome to read it!