scada protocols

Network Layer 2 (IPv4 and IPv6 addresses and related protocols) IP (internet protocol) protocol is the core protocol of the TCP/IP protocol family and the network layer of the internet. The current version number is 4, also known as IPv4. The next generation IP protocol version number is 6, that is, IPv6. As described in the network layer function, the IP layer provides the selection and forwarding functions for the Internet. Hosts connected to the In

"routing IPX add/set staticroute, "routing ipx set global" indicates configuring global IPX route settings. SPX Protocol (Sequences Packet Exchange). The SPX Protocol is based on Xerox SPPSequences Packet Protocol, it is also a network protocol for LAN developed by Novell. In the LAN, the SPX protocol is mainly responsible for error-free processing of the entire transmitted data, that is, error correction. Application: the SPX protocol is generally used in combination with the IPX protocol desc

protocol, the implementation of the constructor needs to be identified by the colleague required and the override modifier:　　Protocol someprotocol{ Init () }class somesuperclass{ init () { //constructor implementation }}class Somesubclass: somesuperclass,someprotocol{ //Because following the agreement, you need to add required, because inheriting from the parent class, you need to add the override required override init () { } }Can fail the constructorYou can add a failed

re-requested if there is any modification .if-none-match: "321397979879-fndlsh32yfsh894392"if the current etag value of the picture does not match the value of the If-none-match, re-requestSecond response header:Status Code 304 not modifiedif it's 304, you think the browser takes data from the local cache, saving the time it takes to transfer the image over the network .Cache for large sites:if the site is larger and has n cache servers, how does the n cache server handle files on the master se

The data link layer has three main purposes: * Sends and accepts IP data packets for the IP module; * Send ARP requests to the ARP module and receive ARP responses; * Send RARP requests and RARP responses to RARP. The ARP protocol is mainly used to resolve the 32bit IP address to the MAC address (hardware address) corresponding to the 48bit (Ethernet ). The RARP protocol resolves the hardware address to an IP address. The two protocols are at the

a static route table. Generally, it is set in advance according to the network configuration during system installation, it will not change as the network structure changes in the future. Dynamic) the route table is the route table automatically adjusted by the Router Protocol according to the running status of the network system. The router selects the Routing Protocol) to automatically learn and remember the network running status, and automatically calculate the optimal path for data transmi

1 Introduction SAN is a private network and the backend of a network server group. It can be connected to a high-speed private network using storage protocols such as fiber channel or iSCSI, so that network servers can be directly connected to multiple storage devices. SAN can achieve many-to-many connections between network servers and storage devices. In addition, this connection is a local high-speed connection. The advantages of the SAN architectu

We have introduced some content about the WAP protocol stack in the above article. For details, refer to the application environment and main protocols of the WAP protocol stack. Next, based on the content of the above article, Let's explain other related knowledge in depth. Wireless Transaction Protocol WTP (Wireless Transaction Protocol) runs on the datagram service. It is a lightweight Transaction-oriented Protocol and is suitable for thin clients

In Internet protocols, the IP address is useless. Without an effective and correct IP Address Allocation, we cannot make the Internet work. Now let's talk about the relevant issues. For the basic content of the IP Internet protocol, please read from below. Addressing There is a difference between the name, address, and route. The name is what we are looking for. The address indicates where the name is located and how the route solves the problem. IP a

In the electrical industry, we should be familiar with RS-232C protocols. As the protocol standard for voltage signal control, it has been applied in many fields. Next, let's take a brief look at this protocol. First, let's explain the specific meaning of this Protocol. RS-232-C The RS-232C protocol is the EIA-RS-232C protocol, in which EIA (Electronic Industry Association) represents the American Association of electronics Industry, RS (recommeded st

Some of our commonly used network applications, such as e-commerce, are implemented at the network application layer. So how can we ensure security in the application layer protocol? In this regard, we will mainly discuss the SET protocol. First, let's take a look at the security protocol environment on the Internet. It is an important issue for e-commerce to handle e-commerce on the Internet and ensure the security of data transmitted between buyers and sellers. To overcome the disadvantages of

We all know that computer networks are divided into seven layers, each of which has its own network communication protocol. We can easily understand the concept of network communication protocol. However, it contains many protocols. Here we will summarize several important protocols to help you make a summary. See the text below. Network Communication Protocol 1: ◆ RS-232-CRS-232-C It is the specification o

, and secondly, it is full-duplex. In terms of reliability, timeout retransmission and RST validation mechanisms are used. In terms of traffic control, the sliding window protocol is used, which stipulates that unconfirmed groups in the window need to be re-transmitted. In terms of congestion control, the slow start algorithm is used. What is TCP/IP? TCP/IP (Transmission Control Protocol/Internet Protocol) is an industrial standard Protocol set designed for WANs. It was developed by research ins

paragraph was only for the condition prior to TLS 1.1. Because SSL is at the next level of HTTP and does not understand higher-level protocols, SSL servers are typically only allowed to be certified to specific ip/port combinations.　　This means that it is often not possible to combine HTTPS with HTTP normally on a virtual host (domain-based). This has been updated by the upcoming TLS 1.1-type full support for domain-based virtual hosts.About SSL　　SSL

Network basics of basic computer series-network protocols and basic computer networks What's the network protocol A computer with hardware, operating systems, and software already has functions that can be used. However, to realize communication between a computer and a computer, a series of standards must be followed.Internet Protocol. The function of Internet protocol is to define how computers access the Internet and how computers connect to the In

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target path next to a neighboring router. Each router is removed and the new data link layer information is added before forwarding.6. Data is transmitted over the Internet, including media and intermediary equipment. The 7.client receives a data link frame that includes data. Handles each layer of protocol headers, and then removes the protocol headers in the reverse order of accession. First, the Ethernet information is processed and removed. The IP protocol information is followed. The next

Concept of security protocol and Authentication Service security protocol for information security HTTPS concept The HTTPS full name hypertext Transfer Protocol over Secure Socket layer is an SSL/TLS-based HTTP protocol located at the application layer. The HTTP protocol for the application layer? The SSL/TLS protocol for the Transport layer. SSL/TLS Concepts is itself a transport layer protocol with encrypted information. SSL: Security

TPC/IP protocol is a Transport layer protocol, which mainly solves how data is transmitted in the network, and HTTP is the application layer protocol, which mainly solves how to wrap the data.Regarding the relationship between TCP/IP and HTTP protocol, the network has a relatively easy to understand introduction:"When we transmit data, we can only use the (Transport Layer) TCP/IP protocol, but in that case, if there is no application layer, the data content is not recognized and if you want to m

We will encounter a lot of protocols in the development process, such as the standard specification class, such as the HTTP protocol, such as Java EE standards and so on. Some people think that these are boring, do not need to pay attention to, but on the contrary, this is very important. protocol and standard specification, is an era of human wisdom crystallization, brings together a lot of cattle and experts wisdom. You need to learn from