The functioning of both local and global computer networks, mobile and other communication services involves the use of various communication protocols. Which of them can be considered the most common? What might be the significance of the relevant standards?
What are communication protocols?
A communication protocol is a list of unified instructions that establish how certain software or hardware interfaces should provide data transfer - for example, text, graphics, audio and video streams. Corresponding protocols are created mainly to facilitate the scaling of various computer networks. For example, the introduction of the TCP / IP protocol made it possible to unify data transmission virtually around the world, which made it possible to connect computers to the global Internet network.
In the modern information technology market, communication channel protocols are used at various levels of implementation of communication interfaces. They are constantly being improved and updated. Periodically, newprotocols reflecting the specifics of the development of the communications market. Various communication protocols can be used in both domestic and industrial networks implemented on the basis of the infrastructure of research centers, etc. Among the most common standards of the corresponding type are Ethernet, CAN, HART.
The use of communication protocols is also carried out in the field of mobile communications services. Among those - 3G, 4G, GPRS.
These protocols vary across mobile networks, in particular:
- according to the speed of data transfer between the subscriber and the communication service provider;
- by frequency bands;
- in terms of the maximum distance of the communication device to the base station.
As for the classification of computer communication protocols, it is characterized by a fairly high level of complexity. Let's consider its specifics in more detail.
Classification of computer communication protocols
Classification of relevant protocols can be carried out using a fairly large number of approaches. A common one is that communication standards can be subdivided into lower and higher levels. These include:
- applied;
- representative;
- session;
- transport;
- network;
- channel;
- physical.
Let's study them in more detail.
Application layer of networkprotocols
The level under consideration, within which one or another communication protocol can be classified, refers primarily to applications. That is, it provides communications between the network infrastructure and specific user programs. Protocols such as HTTP, Telnet, DNS, IRC, BitTorrent and many others are used here to deliver modern online services.
Representative layer of network protocols
At the appropriate level, the communication protocol involves the representation of certain data. Here, procedures for converting one protocol to another, encoding, file compression, and managing various requests can be carried out.
Specific applications make certain requests to the network, after which they are converted into a language understandable to the server. Next, the request is processed. The response from the server is then converted, in turn, into a language that the application understands. Among the popular protocols of the corresponding type are ASN, FTP, SMTP. It can also be attributed to some extent to those and HTTP, FTP.
Session layer of communication protocols
At this level, the communication protocol is used to perform a specific operation - for example, synchronizing certain tasks, creating a communication session, sending or receiving a file. Among the common protocols that are used for such purposes are ASP, DLC, SOCKS.
Transport layer of communication protocols
Appropriate type of standards are used todirect delivery of certain types of data from one network object to another. In many cases, files are divided into separate elements here - in order to facilitate their transfer. Protocols of the corresponding type include TCP, UDP, RMTP.
Network layer protocols
The next type of standards on which a communication system can operate are network layer protocols. They are primarily responsible for data transmission methods, address translation, switching, monitoring the quality of infrastructure operation. Such protocols include, in particular, the same TCP / IP, ICMP. DHCP.
Link layer protocols
These standards are used to ensure the functioning of key hardware components of the network. Appropriate protocols allow the system, first of all, to check the data coming from the physical layer for errors. If necessary, they are also adjusted. Among these standards are the common PPP communication protocol, algorithms such as SLIP, L2F, PROFIBUS. In principle, Ethernet can also be classified as a channel protocol.
Physical protocol layer
The next level of action of the standards in question is physical. Here, a communication protocol is a tool by which a digital data stream is directly transmitted - by sending a signal over a cable or over a radio channel.
In the case of wired transmission, standards such as RS-232, xDSL, 100BASE-T may be used. Common Wireless Communication Protocols - inin particular, implemented using Wi-Fi routers - those that are of the IEEE 802.11 type.
The classification of standards we studied can be considered very conditional. So, within it, it can be very problematic to attribute one or another protocol to a specific category: it often happens that the standard is applied at several levels at once. It would be useful to consider in more detail the specifics of the most popular protocols on the modern information technology market. Such as, for example, the PPP control protocol (communication - it is she who is the object of influence of the algorithms that are provided for by the corresponding standard).
What is PPP protocol?
The protocol under consideration refers, as we noted above, to standards that are designed to ensure the functioning of the network infrastructure at the data link layer. It is universal: using the appropriate protocol, you can implement device authentication, use a data encryption mechanism, and, if necessary, file compression.
The protocol under consideration ensures the functioning of networks based on common communication resources - such as telephone lines, cellular communication channels. If in a particular program an inscription pops up stating that the PPP protocol was interrupted by communication, then this will most likely mean that the user cannot get actual access to network resources that are provided by his provider.
There are several varieties of the corresponding standard - for example, PPPoE, PPPoA. AtThis structure of the protocol in question includes several standards: LCP, NCP, PAP, CHAP, MLPPP. Another common protocol in the modern IT market is
What is the HTTP protocol?
The corresponding standard is used to ensure the operation of the hypertext data exchange infrastructure - in the general case between computers and servers on the Internet. Refers to the fundamental protocols that ensure the operation of the World Wide Web. It is supported by default by most modern communication software tools on common operating systems. It is stable - it is difficult to imagine a situation in which a message from an HTTP program pops up on the user's screen like "the protocol was interrupted by the PPP connection." As a last resort - if for some reason the tools to enable the HTTP standard are not available, you can use, for example, the FTP protocol to transfer files online, although in many cases its use may not be the most optimal solution.
The standard in question involves the transfer of data from a hardware-software object in the status of a client to a server and vice versa. The first sends requests to the second, and the latter answers them according to the established algorithm. There are several varieties of the protocol in question: for example, HTTPS, HTTP-NG. The main advantages behind the fact that the HTTP communication protocol has become one of the most popular:
- versatility;
- ease of implementation;
- expandable;
- wide support from software vendors.
He also has a number of shortcomings highlighted by experts:
- quite a large number of individual messages;
- unsuitability for distributed computing;
- the inability to navigate through the resources hosted on the server.
We noted above that the communication standard in question is supported by the main user operating systems, as well as common software products. However, the scope of this protocol is much wider than the implementation of communication algorithms within user solutions. The HTTP standard is also applicable in industry, video surveillance systems, and SCADA infrastructure.
A large number of manufacturers, considering various communication protocols in networks as basic for building a communication infrastructure, choose HTTP as a functional and reliable tool for organizing access to various online resources, configuring objects, managing various devices.
If we talk specifically about the industry, then Modbus can be attributed to the number of the most popular protocols in the corresponding market segment.
What is the Modbus protocol?
The relevant standard is mainly used to ensure interoperability between various elements within the automation infrastructure in the workplace. Relevantthe protocol can be in those varieties that are adapted to data transmission over a specific type of communication channel - wired, wireless (in turn, the resources of the first type can include copper, fiber optic cables - and separate modifications of the protocol in question have been developed for them).
There are versions of Mobdus adapted to transfer data over TCP/IP. Another popular solution in the industrial environment is PROFIBUS-FDL.
What is the PROFIBUS-FDL protocol?
The protocol under consideration operates within the PROFIBUS network, which has become widespread among European industrial enterprises. Its prototype was developed by Siemens specialists and was to be used in production areas where controllers were involved.
Subsequently, on the basis of the developments of the German corporation, a network infrastructure was formed, in which various technological and functional features of serial communications related to the field level were combined. The network protocol under consideration made it possible to integrate various types of automation devices within a single production system. It is worth noting that the PROFIBUS-FDL protocol is not the only one that operates on this industrial network. However, it is uniform in terms of applicability in order to organize access to the main bus.
One way or another, the communication protocol in question is supplemented by the following standards:
-DP;
- PA;
- FMS.
The PROFIBUS DP protocol is used fororganization of data exchange between leading industrial devices such as DP, as well as devices on which I / O is implemented according to a distributed scheme. At the same time, this protocol allows organizing data exchange at a high speed. It also features a relatively low implementation cost, which may make it popular with smaller businesses as well.
The PROFIBUS PA standard allows data to be exchanged between the infrastructure, which consists of equipment related to the field level. This protocol is optimized for connecting various sensors and mechanisms to a common linear or ring bus.
The PROFIBUS FMS standard is characterized by versatility. It is intended primarily for organizing data exchange between high-tech industrial infrastructure components - computers, programmers, controllers.
Among the strengths of the protocols operating in the PROFIBUS network are openness (that is, they can be used by any interested industrial enterprises), widespread (which makes it easier to scale the industrial infrastructure when expanding markets, opening new industries).
CV
So, we have considered the essence of communication protocols, studied the features of some popular varieties of the corresponding standards. Their main purpose is to ensure data transmission within unified formats. That is - those that can be scaled within the framework of the infrastructure, as a rule, significantly exceeding the scaleindividual enterprise.
In fact, we are talking about international standards: modern protocols for cellular, wired, Wi-Fi communications are very widespread, publicly available, and relatively easy to scale. Of course, in some cases, even in such global markets as the provision of cellular services, it is possible to use regional protocols, but it is in the interests of the largest brands to implement, if this does not contradict the interests of business, and in some cases the state, as unified standards as possible, which will enhance international communications.
There are a number of fundamental communication protocols. In the context of the Internet, these include HTTP, TCP / IP. In the segment of services for providing access to the network, the PPP standard can be referred to as such. If the user sees a message stating that the PPP link control protocol has been terminated, then the user will most likely not be able to access online resources using either HTTP or TCP/IP. Thus, each standard is of great importance and, moreover, in many cases is inextricably linked with others. If one protocol is interrupted by communication, then there is a possibility that the user will not be able to access those resources for which other standards are responsible for organizing communications.
Communication protocols are an indispensable tool for solving complex problems both in the field of user communications, and in industrial and service areas. From the competent choice of a specific standard depends on the success of the implementation of the appropriate infrastructure, as well as itsefficiency - in terms of the ratio of system performance and the cost of its installation. Thus, early study of the properties of network protocols, choosing the optimal one is an important task for enterprise managers responsible for the implementation and modernization of the company's communication infrastructure.
