In the future with IPC
Thanks to fast development of computer processing techniques and increase in number of broad-band networks traditional analogue phones step-by-step concede a palm tree of superiority of an IP-telephony
It is already difficult to imagine a life without computers. Today these useful arrangements practically everywhere. Presented by the big and small arrangements, released hundreds millions pieces they help with our hard life, handling enormous streams of the information. But so was, of course, not always.
The appeared in the mid-forties, electronic computers which have appeared in the mid-forties in the course of the evolution have rather fast transited path from the big computing monsters to compact personal desktop and transportable arrangements (a Fig. 1).
Fig. 1. From ENIAC to the modern desktop computer
Thanks to perfection of processing techniques and architectures their computing power promptly increased, often overtaking forecasts of the known empirical law of Moore predicting regular doubling of number of units on semiconducting crystals of chips. Certainly, in a parallel way with complexity of chips and their high-speed performance functionality of personal computers (PC) grew also. It has provided the extension of consumer properties and implementation of many before unavailable possibilities.
However, despite all it, there were the tasks which are not subject to single PCs. It has demanded multiplexing of computers in a network of different level of complexity. Appearance of networks has provided not only the extension of a spectrum of solved tasks, but also more optimal maintenance of the equipment at the expense of municipal usage of accessible hardware-software resources.
There are the different patterns of networks differing both topology, and technical parametres. However all solutions are banked by that for informational interconnection of computers communication circuits use. They provide high-speed transmission of figures between arrangements. Thus the information can be handled or wireless way, or by means of cables.
Despite perspectivity and convenience of a wireless information transfer, the majority of networks now is under construction by means of wire communication circuits. It concerns also local area networks with rather small number of computers – units, tens or hundreds arrangements, and global where the quantity of computers, is quite often calculated already by millions. And it is finite, for high-speed transmission of the big streams of the information appropriate transmission lines of data are required also.
Before recent time computers were jointed in a network exclusively by means of the cables created on the basis of metal explorers: coaxial and-or twisted pairs. At all advantages of these variants it is necessary to mark, that they already far not always correspond to fast increasing requirements. First of all, it concerns pass-bands — the parametre characterising ability of transmission of great volumes of the information: the bar — less transfer time of files is more . Necessity of growth of a pass-band of communication circuits is dictated by prompt growth of productivity of the computers handling the increasing information contents for smaller time.
Alas, for traditional metal explorers possibility of increase in a pass-band is limited by physical laws. Really, with attempts to increase the given parametre the problems linked to influence of capacity and inductive properties of lines which distort the form of handled digital signals increase. Besides, it is impossible to dump about scores and inevitable losses in lines. The part from them is linked to an active component, and a part - with emanation. In addition to all problems also the prices for nonferrous metals used in cables permanently grow.
Many of the specified lacks the fiber-optical lines representing, as a matter of fact, dielectric wave guides, created on the basis of thin (about 100 microns) are deprived quartz glass threads — amorphous modification of oxide of silicon (a Fig. 2).
Fig. 2. A quartz thread in the protective plastic shell
The information transfer is carried out by means of light signals of a microwave wave band: the infra-red band with length of waves from 0,8 to 1,6 microns that there correspond to frequencies more than 100 000 000 000 000 Hz usually uses .
The fiber optics has received today wide development and is applied in various areas of a science and engineering. Optical fiber production is estimated already in millions kilometres. Rates of growth of fiber optics and optoelectronics in the world market anticipate many other things branches of engineering and reach 40 % a year.
Optical cables form on the basis of the quartz glass alloyed by special additives in which quality rare-earth units and their interconnections usually are applied. Such cables possess many advantages. Major of them concern:
· broadbandness that means possibility of transmission of the big streams of the information; small losses and, accordingly, the big lengths of sites without usage of additional amplifiers;
· small values of diameter of cables and their weight (1 km svetovolokna without the protective shell has weight less than 40);
· security from external actions and a crosstalk (optical cables can be made close with supply lines and high-frequency arrangements);
· high reserve of an information transfer;
· a galvanic isolation of units of a network (absence of the electrical contact electrode);
· absence of an arc drawing and short circuit in cables.
The enumerated advantages became a consequence of changeover of a current flow in the metal wires used for an information transfer, on light in special cables (a Fig. 3). It is necessary to add, current technologies provide reception of photofiber of very high transparency: in a loss working range can be less than 0,1 db on km.
Fig. 3. An example of a fiber-optical cable
To estimate revolutionism of the given transition, it is enough to recollect, that light represents electromagnetic oscillations of very high frequency, by the way, much bolshej, than in case of habitual radio. This circumstance provides very high information capacity of optical channels unavailable to other resources, including radio-waves and even traditional wire lines, including the best types of "twisted pairs". And it is real, metrics of capacity of optical channels already today on usages above, than for the informational lines constructed on the basis of copper cables.
And still the optical fiber is unreceptive to electromagnetic fields that removes some typical problems of copper communication systems. Here and the reserve following from practical impossibility of interception in optical channels of the transferred information, and their noninterference eliminating deformation of handled signals.
Today optical networks are capable to handle a signal to the big distances with the extremely insignificant losses, by the way, much smaller, than in case of traditional wire solutions.
However, in spite of the fact that this processing technique remains while rather not cheap, the prices for optical components fast decrease, while possibilities of copper lines come nearer to the limiting values and demand the increasing expenses for further development of this direction. With the registration of pass-bands optical cables already are quite competitive today, though demand certain modification of a network infrastructure.
Information transfer methods
Today networks quite often bank a considerable quantity of the computers remote from each other on the big distances. It leads layings of rather long communication circuits that affects cost of the organisation and network maintenance. One of methods of lowering of the common expenditures is usage of methods of compaction of the information that allows not only to reduce quantity of transmission lines, but also to increase capacity.
In optical systems of transmission the same methods of derivation of multi-channel link, as in usual systems of transmission on an electrical cable are applied. The fulfilled methods of frequency and time sharing of channels treat them kindly. In all cases of an optical information transfer modulation of the optical carrying is provided. And already in the promodulated sort the light signal is handled on the optical channel, providing transmission of huge streams of the information.
Understanding perspectivity of the optical processing techniques, many companies carry on the intensive researches linked to their development. Implementation of the received results become appropriate production.
As an example it is possible to result optical transmission media of data of company Cisco which are the recognised world leader in the field of network processing techniques. In addition traditional to components which fiber-optical cables concern, laser LED (raying) and fotodiodnye (accepting) converters, company Cisco has presented on the market the next products concerning construction of DWDM-networks. Here it is necessary to remind, that DWDM means Dense Wavelength Division Multiplexing — spectral channelizing. The processing technique is grounded on usage of light waves of various length (a Fig. 4).
Fig. 4. Information processing and data transfer by means of DWDM unit
It provides multiplexing and data transfer on the optical channel of several signals from different sources. Thus each signal is handled on the wavelength therefore on one optical fiber it can be handled more than 1000 trunks. It is necessary to add, that in cables than ten standard veins of an optical fiber (a Fig. 2 and a Fig. 3) can use more.
Theoretically, usage of such leading-edge technologies as DWDM, can give sufficient capacity with which help it it it would be easy to handle all telephone talks of a planet of all on one optical fiber (on one vein of an optical fiber, a Fig. 2).
Multiservice transport platform Cisco ONS is put in a basis of new solutions of DWDM-networks 15454 MSTP.
This platform uses the newest optical amplifiers, multiplexers and recustomized transponders (transponder from transmitter-responder — the transmitter-respondent).
Hardware functionality of DWDM-platform Cisco ONS 15454 MSTP includes transpondernye maps, makspondery (allow to organise simultaneous transmission of 4 streams STM-16 on one wavelength), advanced amplifiers, flexible optical multiplexers of input/output (a Fig. 5).
Fig. 5. DWDM-platform Cisco ONS 15454 MSTP and a set of maps
Not enumerating all other components, it is necessary to mark, that Cisco offers completely completed solutions, allowing to create multipurpose networks.
The house videophone
One of the major applications of broad-band multicomputer networks, including an Internet wide-area network, processing and an information transfer which increasing share is made by multimedia files are. These files carry video and the audioinformation of users of computers. As a rule, their transfer time is not critical though, of course, growth of capacity of lines increases comfort level.
However the pass-band increase provides also new functionality. It as in philosophy: «quantity transition in quality». High capacity allows not only to reduce transfer time of volume multimedia files, it still gives to handle some of them in real time. It is a question of video and the audioinformation submitted directly from a source. Processing, transmission and reception in real time allows to parse at once such information and to undertake necessary operations. And it already changeover of a telephony and transition to a video telephony. And all information can be handled in uniform, a digital form within the limits of a computer network.
Really, what for to duplicate streams at the expense of usage of analogue and digital cables? Whether to leave only broad-band lines easier? At the first stage it can be and copper wires, but already in the near future they will be replaced by the optical.
As to traditional analogue phones their peak of their popularity is already transited. It is linked by that an analogue signal today simply enough to transform into a digital form representing sequence of already habitual binary nulls and units.
After processing by computer resources the digital sequence can be divided into packages, having supplied with an appropriate housekeeping information. In it addresses of the remailer and the receiver, number of packages, etc. Such packages contain it is possible to handle not only within local area networks, but also to send in the Internet. Presence only appropriate programs Is required.
So popular system Skype works. Free of charge having hooked up in this system with the help besides the free program, users have an opportunity audiolinks with those who has installed the program with the same name on the computer with the on-line font type. It is possible to use instead of font type a separate microphone with headphones (or speakers).
Thus operation in an Internet network is subject to payment only, and link is free irrespective of distance, layout of computers and duration of conversation. Well and in addition to it there is a possibility of paid link with traditional phones and is return.
And within the limits of the specified system it is possible to handle together with the audioinformation also video. It is reached by means of the on-line web camera. The given functions transform traditional computer resources into the videophone that translates communications to another, more high level.
Certainly, all it becomes possible at an appropriate pass-band of a network: as shows experience, the low bound is in area 128 Kbit/with though absence of delays in transmission and reception of digital packages is not less important. For rather problemless audio and visual communication within the limits of system Skype transfer rates 256-512 are quite comfortable Kbit/with.
Certainly, described free system is a break in communications. However that quite suits house application, not always suits corporate users.
VoIP and an IP-telephony
For exacting users it is necessary to pay attention to firm solutions of company Cisco which experts professionally deal with a problem of convergence of audio/video of the information with the computer data handled within the limits of one IP-network.
The processing technique of link on IP-networks (IP Communications, IPC) is mastered all more widely. According to corporation IDC, in 2006 50 % of all communication traffic it will be handled on IP-networks. It is linked by that the companies even more often consider IPC as necessary solution for an expedition of a recoupment of investments. IPC provides data transfer and voices (at the expense of conversion of vocal signals to the packages similar to packages of data) simultaneously on the same network (a Fig. 6). Besides for rise of efficiency of business processes of the task of telephony and data transfer it is possible to combine in the uniform application.
Fig. 6. Development of the market of IP-communications
By the way, estimating advantages of solutions of an IP-telephony, it is necessary to mark, that behind the term "IP-telephony" two independent processing techniques disappear: a VoIP-telephony and a corporate IP-telephony. When communication statement service is spoken about a VoIP-telephony it means that means, as a rule. It is service of long distance calls which are cheaper than the usual.
When it is spoken about a corporate IP-telephony the way of the organisation of telephony in one or at all offices of the company more often means. The corporate IP-telephony allows to save as on calls between offices (similarly VoIP-telephony, but without involvement of a communication statement), and on expenditures on support of system of a telephony. That is, when economic attractiveness of a corporate IP-telephony it means that maintenance and interoffice telephone traffic is cheaper is considered.
It was historically added so, that has initially appeared and the VoIP-telephony has received a wide circulation, and already then systems of a corporate IP-telephony everywhere began to take root.
It is necessary to mark, that for solution of all arising problems company Cisco has completed variants of hardware-software products which she actively offers potential users. For popularisation of the reachings and rise of attractiveness of the solutions it regularly carries out appropriate actions, for example, such, as «Test drive of an IP-telephony and office processing techniques».
Within the limits of the given initiative during the period from September till November of this year of firm of average business in aforementioned cities can familiarise on preliminary writing with possibilities of a modern telephony on the basis of unified communications Cisco. For this purpose it is required to call by phone to the regional representative of company KROK or to fill the electronic demand for a site of the given program. Test drive will transit in specially created demos-centres on the basis of regional companies KROK Urals Mountains, KROK the Volga region, KROK Siberia, the Northwest KROK and KROK the South.
However if critically to consider possibilities of an IP-telephony, how leading experts Cisco mark, the main advantages and improvement of quality of a life from a corporate IP-telephony are received not by usual managers, and company management (which saves on each call of the employee) and technical experts it becomes easier to them to service telephone system. The simple business employee, the manager, does not see a special difference between simple phone and IP-phone.
Nevertheless, it is necessary to mark the important role which has played and the corporate IP-telephony continues to play. The corporate IP-telephony represents the last, preparatory stage before approach of an era of the unified communications. Universal successful implantations of a corporate IP-telephony have proved, that for the organisation of a voice communication in the company it is possible and it is necessary to use possibilities of a computer IP-network. Possibility of inclusion of "telephone buttons» practically in any program window on the computer screen (since program phone, Outlook and ending a web-page) has created premises for appearance of new representations how link - link between people with normal feelings of comfort actually can look.