Satellite communication has the most important advantages necessary for building large-scale telecommunication networks. Firstly, it can be used to quickly form a network infrastructure that covers a large area and does not depend on the presence or condition of terrestrial communication channels. Secondly, the use modern technologies access to the resource of satellite repeaters and the possibility of delivering information to an almost unlimited number of consumers at the same time significantly reduce the cost of network operation. These virtues satellite communications make it very attractive and highly efficient even in regions with well-developed terrestrial telecommunications. Moreover, at present, many companies with a geographically distributed structure are extremely interested in reducing the cost of paying for communication services and are increasingly refusing network services. common use, preferring to create their own more cost-effective satellite communication networks. The modern market for satellite communication services and systems is replete with a wide range of technological solutions for building such networks, and choosing the right satellite technology for your enterprise becomes a very difficult task. How to approach it correctly? To whom to entrust the construction of a corporate network?
Topology
First of all, you need to clearly formulate the telecommunications needs of your enterprise - after all, the efficiency of the future network largely depends on a correctly compiled terms of reference. It is necessary to determine the network topology - the scheme of connections between its nodes, which are most often the branches of the enterprise. At the same time, it should be taken into account that communication via a geostationary satellite introduces a noticeable delay in signal propagation, therefore, in some cases, the use of “double hops” of the signal, which doubles this delay, is highly undesirable. In addition, redundant connections often add complexity and cost to the network.
In networks with single center information processing, the services of which are used by many remote branches that interact weakly with each other, use a star topology. In such a network, communication between branches is carried out through a central node. In cases where the exchange of information between individual branches is particularly intensive, it is advisable to implement a mixed network topology, where these branches will be directly connected. Such a topology can often be found in banking networks and in factories with centralized control and a wide network of regional branches, distributors or product suppliers. These networks often form regional subnets with their own specific technological features.
In networks where the connection of all branches with each other must be carried out with a minimum delay in signal transmission, a fully meshed topology should be implemented. In this case, each node of the network will be able to establish a direct connection with any other node. This topology is used in corporate networks with large and multidirectional telephone traffic, as well as in data transmission systems with random connections between their nodes and strict requirements for time delays. The advantages of this topology are indisputable, however, its use is not economically justified in all cases.
For every telecommunications service your business needs (telephone, facsimile, or data), it is important to determine the optimal topology and technology for a satellite communications network and try to implement an integrated communications system that supports them.
So, we have decided on the network topology. Next, you need to estimate the volume of traffic transmitted over it - the task is quite difficult, especially for enterprises that this moment are developing intensively and plan to eventually complete a complete refurbishment of their communications infrastructure. In such cases, it is recommended to use technologies that can evolve “in step” with the growing needs of the enterprise, however, it is still necessary to estimate the volumes of initial and prospective traffic. To do this, you can go the way of extrapolating data on the load of existing communication channels (which include the size of typical transmitted messages, as well as the duration and frequency telephone conversations per certain period time) taking into account the planned growth in the number of network users. When calculating network load, you need to use the amount of traffic during peak hours, when it is maximum. It is also important to take into account changes in the volume of traffic depending on the direction of data transmission over each of the network channels, since with the help of satellite technologies you can create channels with asymmetric bandwidth. Knowing the requirements for acceptable time delays for all types of network traffic, you can use their priority system, which increases the efficiency of network resource allocation.
Given the high importance of the task of predicting the amount of traffic in the network, it is recommended to entrust its solution to specialists with extensive experience in planning and operating such networks.
Any satellite communications network includes one or more relay satellites, through which the interaction of earth stations (ES) is carried out. Currently, the most widespread satellites operating in the frequency bands C (4/6 GHz) and Ku (11/14 GHz). As a rule, C-band satellites serve a fairly large area, and Ku-band satellites serve a smaller area, but have higher energy, which makes it possible to use satellites with small-diameter antennas and low-power transmitters to work with them. The communication satellite is selected based on two criteria: the configuration of the service area (it must match the geography of the corporate network) and the cost of the channel (including the cost of the satellite transponder and ES required for its formation). Attention should be paid to the guaranteed service life of the selected satellite and the statistics of malfunctions of spacecraft similar to it.
Technology
Any ZS includes radio frequency and channel-forming equipment. The first is the antenna and transceiver, which must correspond to the type of the selected satellite and ensure the operation of the channel-forming equipment. As a rule, these two components of the AP are supplied as a kit.
Channel-forming equipment determines the principle of operation of the AP and the entire network. Currently, there are four main technologies for satellite communication networks. All of them have their advantages and disadvantages, and none of them is universal. Many of today's networks successfully combine multiple technologies simultaneously to improve performance. The main difference between them is the way in which the resource of the satellite transponder is used. Let's take a look at these technologies.
- · SCPC (Single Channel Per Carrier) is actively used to build small networks with heavy traffic. Each ES implementing SCPC has a dedicated permanent satellite transponder capacity segment and maintains a permanent connection. The main advantage of this technology is that it guarantees the necessary bandwidth of the satellite communication channel, and the main disadvantage is the lack of the possibility of dynamic redistribution of the relay resource between network nodes.
- · DAMA (Demand Assigned Multiple Access) provides satellite transponder resource on demand. In networks with DAMA technology, the communication channel is allocated to the user only for the duration of the communication session, which significantly saves the resources of the satellite transponder. The channel structure in this network is similar to that of the SCPC channel. In some implementations of DAMA technology, it is possible to establish connections with different bandwidth for different communication sessions. DAMA is optimal for creating telephone networks with a fully meshed topology. The relay resource is distributed by the central station of the network, which can be considered the main drawback of the technology, since the functioning of the entire network depends on the state of this one station.
- · TDMA (Time Division Multiple Access) provides multiple stations with dynamic access to a common time division channel. Unlike DAMA technology with its rather long connection establishment time, such access is provided much faster. However, TDMA ESs are quite expensive, since any of these stations - even with the most minimal traffic - must transmit data at a rate equal to the total bandwidth time-shared channel. In TDMA networks, there is usually no central control station.
- · TDM/TDMA (Time Division Multiplexing/Time Division Multiple Access) - combined technology of networks with star topology. In a TDM/TDMA network, the central station communicates with user stations using one or more dedicated TDM channels (with time multiplexing), and user stations access the central station through TDMA channels. Since all user stations directly interact only with the central ES, it becomes possible to use rather low-power stations, compensating for the lack of their energy by using a large-diameter antenna and a powerful transmitter at the central ES. Due to such an imbalance of station parameters, it is possible to significantly reduce the cost of projects with a large number of user stations. The obligatory presence of a central station (which acts as a network concentrator) determines the high requirements for its readiness, because the functioning of the entire network depends on the state of this station.
In a TDM/TDMA network, data transmitted between any two user stations passes through the repeater satellite twice (“double hop”). In this case, a significant (1-2 s) signal delay occurs, which makes this network unusable for telecommunications applications that are sensitive to such delays.
Support for the above basic technologies is implemented in many modern satellite communications hardware. It often makes sense to use several technologies simultaneously on the same network. So, for example, to build a large-scale corporate telecommunications infrastructure, a combination of TDM/TDMA and DAMA technologies can be recommended. The last of these will provide telephone and facsimile communications, make it possible to organize audio and video conferences, while using the TDM / TDMA subnet it will be possible to carry out data transmission.
Usually, in order to develop the optimal network solution, calculate the cost of several options for building a network (based on one or more technologies) with various modes download it. If network development is planned, then for right choice technologies (of course, from among those suitable to provide the telecommunications services necessary for the enterprise), in addition to the cost of implementing the initial network version, it is necessary to estimate the total cost of owning one user station and the change in this indicator with an increase in their number (see figure). When constructing the graphs presented in the figure, it was assumed that the user stations are equipped with one data port with a traffic of 10 Mb per month and one telephone port with a traffic of 1000 minutes per month, and the network has a star topology. As can be seen in the figure, in a network with 10 user stations, in the case of using TDM / TDMA technology, the total cost of owning one such station for three years will be quite a large figure - approximately $ 110,000, but with the growth of the network it will decrease very quickly . In smaller networks, it is much cheaper to use SCPC or TDMA terminals, however, when the number of such terminals exceeds 50, they cost more than TDM/TDMA user stations. It should be noted that the total cost of ownership of the station is greatly affected by its load.
I would like to give some general advice on the optimal choice of equipment and its manufacturers. First, it is worth analyzing the experience of other companies that have already been operating the equipment you are interested in for at least one year. Second, collect as much information as possible about the equipment manufacturer itself, including its history in the market, current financial situation, and the quality of support provided in planning and operating the network. Pay attention to the possibility of providing various communication services within a single hardware platform of a particular manufacturer, the degree of its integration with other platforms of the same manufacturer, and whether it has certificates of compliance with Russian and international standards. The absence of these certificates can lead to a complete failure during the implementation of the network project.
Construction
Many enterprises follow the path of creating their own telecommunications divisions, placing the development, construction and further operation of the corporate network on the shoulders of their employees. At the same time, they get full control over their networks and save on paying for third-party services. However, it is not always possible for enterprises to hire highly qualified personnel with knowledge of the technologies that are expected to be used in the future network, and the additional costs of training such personnel and solving complex problems that often arise during the implementation of the project can significantly exceed the savings.
At the same time, the operation of the network will require obtaining various permits, and this is a rather laborious, expensive and time-consuming procedure. It is easier, and often cheaper, to use the services of a well-known operator with experience in implementing similar projects and the necessary licenses. If an enterprise wants to independently control and maintain its network, that is, to be its operator, an external operator can be used only at the stages of development and implementation of the network project. During this time, the company's own specialists will be able to receive the necessary training in order to then take over the administration and maintenance of the entire network.
However, it is not at all necessary for an enterprise to build its own network, since all the communication services it needs (with the leasing of user stations) can be provided by an operator that already operates such an infrastructure. This will allow the enterprise to avoid the financial risk associated with large investments in the design and construction of its network. If network ownership is of fundamental importance for him, then over time he can buy out the stations and, when the network reaches a significant scale, and the satellite technology used in it proves to be effective in meeting the telecommunications needs of users, rent a satellite repeater resource, build his own central station and switch user stations to it.
Exploitation
So, the network is built and put into operation. However, for successful operation, it must be properly serviced. The fact is that even the most reliable equipment sometimes breaks down. According to statistics, the maximum failure occurs in the first year of its operation. Naturally, manufacturers provide warranty repair own equipment, but this process is lengthy - from a month or more. In this regard, the enterprise needs to have its own warehouse of spare parts for all types of electronic equipment of the network, and for this it is necessary to allocate premises and hire people who will release these spare parts, store, transport them, etc. In addition, qualified specialists will be required who are ready to as soon as possible go to the place of installation of faulty equipment with spare parts and measuring instruments. It should be noted that the acquisition of measuring equipment and maintaining it in working order require significant costs.
For an enterprise, maintaining the network on its own is economically justified only with a large (more than 100) number of stations. That is why many corporate clients around the world, including in Russia, prefer that this be done by operators who already serve a large number of networks and have a staff of highly qualified service specialists, a warehouse of spare parts and the necessary measuring equipment.
In conclusion, I would like to give one more piece of advice: when choosing satellite technology for your enterprise, try to develop a single concept for using intra-office communications tools, basic network software and infrastructure for information exchange between branches. This approach will allow you to choose the optimal combination of communication technologies and ensure the flexible operation of your communications infrastructure for many years to come.
The corporate network makes it possible to unite territorially remote divisions of large companies with an extensive structure anywhere in Russia. CJSC "DOZOR-TELEPORT" provides high-quality communication on high speeds, whose cost is not affected by the distance between connected points.
CJSC "DOZOR-TELEPORT" within the framework of the corporate network offers the following services: data and voice traffic transmission, videoconferencing and video surveillance, high-speed Internet access and much more.
Corporate networks are:
Development integrated solutions and provision of the entire cycle of work performed to create a corporate network
Ease of integration into the existing terrestrial telecommunications infrastructure of the subscriber's corporate network
Full control and easy scaling
A characteristic feature of the technology that distinguishes it from others is the ability to create a corporate network with an individual set of services. It can be supplemented and expanded at any time without great expense. The solution of CJSC "DOZOR-TELEPORT" makes it possible to independently adjust the number of services and manage them remotely.
The IP VPN corporate network is based on modern MPLS (Multi-Protocol Label Switching) spectral multiplexing technologies. This configuration ensures the security, quality and reliability of the network solution service. The technology makes it possible to process data at high speed, has great capabilities for managing network traffic, and provides a high level of communication confidentiality.
CJSC "DOZOR-TELEPORT" pays much attention to the protection of information and confidentiality. Security in the network of CJSC "DOZOR-TELEPORT" is technologically integrated with the iDirect satellite technology platform used, which has several protection lines and is created at all stages of the passage of voice traffic and data within the network.
Satellite corporate communication channels created using the broadband satellite network of DOZOR-TELEPORT CJSC are divided into two groups, the first ones use terrestrial communication channels, and the second ones do not.
Corporate networks without the use of terrestrial communication channels
To organize a corporate network without using terrestrial communication channels, VSAT terminals of DOZOR-TELEPORT CJSC based on iDirect technology are installed at all customer sites. Depending on the location of the object and the required data transfer rates, CJSC "DOZOR-TELEPORT" provides the opportunity to work on various communication topologies.
The Zvezda topology is the most common communication organization scheme today, this topology requires the least amount of costs on the part of the subscriber, makes it possible to provide data transfer at a speed of up to 4 Mbit / s between VSAT terminals with landing at the Central Communication Center of CJSC "DOZOR-TELEPORT" . This topology is best suited for subscribers with low traffic and non-delay critical applications. Since data transmission is carried out in two satellite hops, the average delay increases slightly, but as already mentioned, the quality telephone communication it doesn't affect.
The topology "Mesh" or fully connected is especially convenient for equivalent enterprise objects that do not have a pronounced centralization from the IT point of view, and the organization of a terrestrial channel is impossible or too expensive. This topology allows you to transfer traffic between two terminals, including those installed at the subscriber's central office, as well as terminals at remote sites, in one satellite hop. The stations are controlled from the Central Communications Center (CCC) of CJSC "DOZOR-TELEPORT" using the central control channel.
Terrestrial communication channels for corporate networks
The use of corporate networks provides the widest range of services for the clients of DOZOR-TELEPORT CJSC.
Traffic (data, voice and video traffic) of subscriber VSAT stations included in the corporate network of the client of DOZOR-TELEPORT CJSC, through satellite channels is sent to the Central Control Station, then transmitted via a ground communication channel to the customer's office.
The terrestrial channel between the NCC of CJSC DOZOR-TELEPORT and the Customer's office in any city in Russia allows:
Ensure the interaction of remote objects with the central office without installing satellite communications equipment at the central office
Use star topology with 1.2m or 1.8m diameter antenna posts while maintaining satellite signal propagation delay of 600 milliseconds (one satellite hop)
Maintain the numbering system and extend the address space of the central office to remote sites.
The corporate network from AltegroSky allows you to effectively unite geographically remote divisions and branches of companies and provide high-quality communication at high speeds. SETTELECOM offers its corporate Clients services for the organization of satellite corporate communication networks for data and voice traffic, high-speed Internet access and long-distance/international telephony. We will organize the connection of your company's central office with remote branches anywhere in Russia, while the cost of the solution will not depend on the distance between the connected points! !Corporate networks are:
Complete independence from ground infrastructure and short network deployment time;
Easy integration into the already created terrestrial telecommunications infrastructure of the Customer's corporate network;
High level of protection and security of information;
The versatility of the equipment used;
Possibility of increasing the total bandwidth of the corporate network and the possibility of its dynamic redistribution between individual nodes or directions;
Possibility remote control corporate network directly from the Customer's office;
Wide range of services and client applications;
One-Stop Shopping - the presence of only one Contractor - "SETTELECOM", responsible for the entire cycle of work on the creation and operation of a satellite corporate network;
Providing comprehensive turnkey solutions;
Ability to minimize investment and operating costs.
In addition to traditional services, SETTELECOM specialists offer solutions for organizing videoconferencing sessions in the Customer's corporate network, broadcasting service information and software, updating databases, organizing remote training of personnel and business television.
Service quality AltegroSky is guaranteed by the use of technology and equipment from the world's leading provider of technological solutions in the field of broadband satellite systems - Hughes Network Systems.
The high quality of service for corporate networks is provided by highly qualified SETTELECOM specialists who have extensive practical experience in operating satellite communication networks and have been trained in the USA. The Network Control Center (NCC) and the Customer Support Service are located in the Moscow Region at the Bear Lakes Space Communications Center.
Satellite corporate networks projected over a broadband satellite network AltegroSky are divided into two groups:
Without the use of terrestrial channels
Using terrestrial channels
Corporate networks without the use of terrestrial communication channels
Such networks are focused primarily on the transmission of data and voice traffic. At all points of the Customer's corporate network, small-sized satellite terminals are installed, which provide data transmission at a speed of 256...819 kbps between terminals with relaying through the NCC AltegroSky. This network configuration is optimal for networks with low traffic and applications that are not critical to the delay in the channel, which is 800-1200 milliseconds depending on the file type. The delay in telephone intra-corporate conversations will be 600-700 milliseconds, while the quality of telephone communication, despite such a delay, will be high due to the fact that telephony in the Direcway satellite network is fully integrated into the satellite platform.
Corporate networks using terrestrial communication channels
These networks are focused on providing the fullest possible range of broadband services for corporate clients. All traffic from remote points of the Customer's corporate network, where small-sized satellite terminals are installed, is transmitted via satellite channels to the AltegroSky NCC and then sent to the Customer's central office via a digital terrestrial channel. With the help of a router, data is sent to the local network server, and voice traffic is sent to the office PBX.
Terrestrial communication channel (speed 64, 256 or 2048 kbps or more) between the AltegroSky NCC and the Customer's central office in Moscow or in any city in Russia allows:
Increase the speed of information transfer in a satellite corporate network several times (from 256 kbps to several megabits per second);
Reduce the delay time in the channel to 350-400 ms;
Provide high-quality telephone communication in the network with a delay of 300-350 ms;
Significantly expand the range of business applications and services supported by the corporate network.
SETTELECOM pays great attention to security and information protection. Information protection in the AltegroSky network is technologically integrated into the used satellite access platform HughesNet has several lines of protection and is organized at all stages of the passage of data and voice traffic within the network.
A satellite corporate network can be deployed across the country in a few weeks, while building landlines, if possible, is a more expensive solution that takes several months to complete.