Disadvantages of IP telephony Why IP telephony is replacing analog communications and who offers such services on the Russian market

Price

Internet telephony services, in comparison with traditional long-distance and international telephone communications, provide great savings. Some Internet telephony companies allow users to make computer-to-computer (user-to-user) calls for free. You pay only internet costs. Also, Internet telephony service providers typically charge a flat rate, which is well below the cost of similar services using traditional telephony providers. By paying a monthly fee, you can get unlimited calling capabilities in certain regions of the world, which can significantly reduce telephone costs for businesses with international branches or for families whose members are abroad.

conference call

Most Internet telephony providers offer a conference call service. The number of possible participants varies from supplier to supplier. This option is usually supplied as part of a service package at no additional cost, giving you an advantage over classic phone services.

Mobility

In order to use traditional telephone services, the user must be in one fixed location. Internet telephony allows you to work in all places where there is access to broadband Internet. Instead of providing service in a specific location, Internet telephony provides service for a specific account. No matter where you are located - in Los Angeles or Southeast Asia, the software provides the user with access to the same service functions.

Internet telephony: disadvantages

Unreliability

Like cell phones, Internet telephony suffers from problems such as missed calls and audio distortion. The functionality of Internet telephony depends on the quality of the broadband connection it uses. Sudden losses in lead bandwidth will result in distortion, time delays, and sudden blackouts. Older computers with slow processors and limited RAM (RAM) may not be able to support Internet telephony calls or may result in deviations from standard call quality.

Limited emergency call

Emergency services cannot trace Internet telephony calls because the calls do not come from a physical location. This makes Internet telephony problematic in emergency situations. In order to fix this problem, it is necessary to connect calls to government services and provide customer address information. However, for now, the very nature of Internet telephony limits the effectiveness of its use for making emergency calls.

Outside the window, the second decade of the 21st century, our satellites plow the expanses of the world's oceans, but I will start talking not about my beloved Asterisk, but about the good old office mini-PBXs in comparison with IP-PBX counterparts. And first of all, I will tell you when and why (IMHO) you should not deal with them.

For the 101st time, I won’t talk about the advantages of IP telephony both for communication with the outside world and within the company, there are a lot of articles on the blog of the same name.

If you're just thinking about setting up a telephone network within your company, and you don't have miles of telephone wires laid and lots of purchased equipment, IP telephony will almost certainly be the best choice for you... But what if you already have something?

Cons of the "traditional" solution:

• The cost of implementation for 1 port, taking into account the work and equipment (laying a cable at the rate of one pair for 1-2 telephones from the PBX directly to the installation site, limiting the length of the link to the digital device at about 150-300m, the price of the PBX and boards for it is calculation for 1 port, labor costs for cross-connection ...).
• Maintenance cost (higher costs for laying a network when moving to a new premises, laying additional lines, the need to reprogram numbers and (and) re-switch ports when transferring a user, changing the type of device: analog / hybrid / digital).
• Much less flexibility in configuring the PBX and its functionality.
• Remote office or warehouse = communication is all the same through VOIP or some other crutches.
• A number of inconveniences in the use of devices (analogue devices lack many convenient functions, and digital ones cost comparable to IP phones + are tied to the manufacturer's PBX).
• The "hybrid" devices from LG-Nortel and Panasonic deserve a separate unkind word. They require 2 pairs to connect to 1-2 devices, use 2-4 memory cells (instead of 1 for 1 digital device), are also tied to the manufacturer's PBX (rarely, but it happens - to a single one).

Advantages of the "traditional" solution:

• With the existing SCS designed for wired telephony, putting undemanding hamsters of office workers on analog phones is the cheapest possible solution. Plus, when switching to IP-PBX, analog handsets can still come in handy at first.
• If we are talking about a working system laid by SCS, then the cost of purchasing a digital device, taking into account the cost of 1 (or ½) port of the board, is even slightly less than IP ... until the issue rests on the capacity of the motherboard.
• Cordless phones, DECT. IP analogs are at least three times more expensive (but they have all the advantages inherent in digital devices).
• Good old fax. I feel like tomatoes are going to fly at me. Alas, for an extensive exchange of fax messages with subscribers outside million-plus cities, the easiest way is ... "analogue" pair of the last mile from our monopolist. You can't please all FXS with T.38 or G.711.

The funny thing is that after many years of working with various solutions, I can not exclaim: - “Everyone is running to buy an IP-PBX!”.
Yes, they are head and shoulders ahead of their rivals in terms of convenience and perfection, but in some cases, when there are about 50-150 users and the infrastructure has already been established, even an evolutionary transition to purely IP solutions within the company is not easy.

What do you think?

The popularity of packet networks is not only a tribute to fashion. This is a conscious step towards improving the quality of services, improving the service component. The principle of operation is the transmission of voice over IP networks. It should be noted that the possibility of introducing this type of service has been discussed for several years, but a full-scale transition to their mass use has occurred relatively recently.

Today, connection to services of this type is available to almost every Internet user. Hundreds of operators provide the service for a relatively small fee. But this type of communication has not only advantages, but also disadvantages. What should you pay special attention to when changing the format of telephone communication?

Basic principles of IP-telephony

Internet telephony is a way to instantly digitize voice and transmit it in separate packages to another subscriber. A sound delay of up to 400 milliseconds is acceptable, which is practically not felt in a conversation. The level of such delay depends on the quality and capabilities of the equipment used by the operator providing the service.

A bit of theory

In order to fully implement all the necessary steps, companies providing communication services can use various equipment. These can be separate, specially designed programs installed on a personal computer, special desktop telephones, or high-capacity gateways.

It is the gateways that are responsible for processing traffic that comes from outside. Each of the gateways (depending on the settings) is capable of serving from one to five thousand telephone sets. This equipment is installed not only at the provider, but also at the end user, provided that the company has the ability to fully service it.

Another type of device used combines a gateway with remote access.

In the wake of the voice

• The call is transferred from the telephone network to telephone gateways, the signal is processed by means of a special card of the voice service device.
• Further, the gateway automatically redirects this information to the gateway located on the side of the receiving subscriber. This is done through the control protocols of the H.323 or SIP family.
• The receiving gateway relays the signal to the receiving telephony equipment using the dial plan as a guide and guaranteeing an end-to-end connection.
• So the connection is established. At the input device, the voice is digitized, then encoded according to ITU algorithms, compressed, "packed" into packets and sent in the opposite direction.

The main pros and cons of IP telephony

First of all, let's figure out what exactly is IP-telephony, the pros and cons of which are actively discussed on the network. At the moment, four types of Internet telephony are widely used.

• The first includes connections involving two PCs equipped with a sound card, as well as a headset.
• To the second - the interaction between a personal computer and a conventional landline phone. Here, for a full-fledged connection, you must use a program pre-installed on your PC.
• The third method involves a connection between two stationary devices.
• And finally, the fourth is to use a VoIP gateway or a phone configured with a SIP server instead of a regular computer.

IP telephony: pros and cons

There are quite a few positives.

• Saving money, especially if the subscriber regularly makes calls to another city or even a country. The standard cost of a minute of conversation in this case is about 15 kopecks, which is significantly lower than when using traditional communication. Such democratic value is formed due to the increase in the sharing ratio.
• Complete confidentiality, which is protected by the relevant protocols of obligations of operators providing this type of communication.
• Possibility to increase the number of lines without any additional costs.
• High quality communication, which is completely independent of distance. The only thing that can affect the signal delay level is the channel load.
• Availability for every Internet user. By becoming a client of one of the four hundred provider companies providing this service, you will be able to use all the advantages of IP-telephony.
• Market volume. The annual turnover in Russia in this segment is more than 60 million US dollars.

The disadvantages include, perhaps, only the need to purchase additional equipment (that is, albeit one-time, but still costs), as well as the complete absence of devices that monitor, correct and fix the level of service.

Internet telephony, what is it? What are its advantages compared to traditional, GSM and city telephony? What do you need to start using Internet telephony? What internet telephony networks exist? Is there a difference between Internet telephony and IP telephony? Let's look into all these issues.

Internet telephony, as the name implies, works through public Internet networks. Most often, this is what it uses for voice transmission and call / hang up signals - ip packets, according to certain protocols. To date, the SIP protocol has received general recognition for ip-telephony, in fact, it helps to find the right interlocutor and send him a call. Voice and video, in turn, is encoded with a voice codec and packaged in RTP packets, and then the TCP / IP protocol stack already decides how it all is delivered to the right point.

In the world, one can boldly single out two commercial Internet telephony networks - these are Skype and Viber.

Viber all the same SIP protocol, to establish a connection, and certain voice compression. All information is stored on centralized Viber servers.

Skype unlike many other systems, it uses P2P architecture for data transfer. The list of Skype users is distributed across the computers of Skype network users, which allows the network to easily scale to very large sizes (currently more than 100 million users, 15-20 million online) without expensive centralized server infrastructure. Prior to the purchase of Skype by Microsoft, the Skype network was one of the most secure.

And of course, most importantly, IP telephony (Internet telephony) is readily used by telecom operators and providers. There is no need to lay a cable and buy expensive equipment, all calls go through an existing Internet network.

What devices are needed for?

IP phone, outwardly similar to a stationary office analog phone, the only difference is that it has its own mini computer inside, and it works via an Ethernet network, and all voice processing is performed by a digital processor.

Softphone, a softphone that allows you to make calls using a computer and a headset. Most of them are completely free and do not require the purchase of any licenses.

A softphone can also be installed on a smartphone as an application and function as a phone in a phone.

Wireless WiFi and DECT phones should be classified as IP phones.

In order to connect an ordinary analog phone to Internet telephony services, you need an analog FXS gateway.

So, what are the pros and cons associated with the use of this technology. Let's start with the benefits. There are actually two of them:

• Internet conversations compressed using the appropriate codec and packed into data packets load communication channels much less than those transmitted using traditional technology.
• Significant savings on telephone calls. Since an international (long distance) telephone operator is not involved in an IP telephone call, the cost of this call is an order of magnitude less than the cost of a traditional telephone connection, and tariffs in this service sector are becoming cheaper and cheaper.

The main disadvantage of Internet telephony for a long time was the potentially lower quality of communication. Moreover, the main disadvantage is the main advantage - packet routing of voice traffic. With a high network load, both the loss of part of the packets and unacceptably large delays in their delivery are possible - hence the loss of words, echo and interference. However, the development of equipment and technology, as well as the Internet itself, has made it possible to reach a level where speech is understood by subscribers so well that the interlocutors do not realize that the connection is made using technology.

Comments:

05/12/2000, Fri, 11:05, Msk

One of the most promising technologies today is packet telephony. The growing popularity of voice transmission over packet communication networks is quite natural in the light of the ongoing convergence of communication networks. With all the variety of possibilities for voice transmission over packet networks, one of the technologies has a clear advantage over others. These are voice over IP networks and, in particular, IP telephony. The transition from the press discussion of the possibilities of Voice over IP technology to the emergence of a wide range of IP telephony products on the market has occurred quite recently. A year ago, IP-telephony was classified as a technology of the future, and at the current Svyaz-Expocomm 2000 exhibition, probably, only a lazy manufacturer did not present its developments for building IP-based multiservice networks. And, apparently, this product is in demand. At some booths, it was products for IP-telephony that aroused the greatest interest of visitors. The growth in popularity of IP-telephony, of course, to a large extent contributed to the manufacturers. However, for the most part, interest in this technology is due to its real merits.

The most important factor that determined the leading position of VoIP (recall that there are also technologies for transmitting voice traffic over ATM and Frame Relay - VoATM and VoFR) is the widespread use of the TCP / IP protocol. This protocol is primarily associated with the Internet, but it is increasingly used in local area networks. The global distribution of TCP / IP makes it possible to use only one protocol for voice transmission over the entire communication line, which greatly simplifies network management. The active use of this protocol in local networks makes it easy to build an integrated service network. Within one organization, using existing equipment, it is possible to build a single information system in which both data and voice will be transmitted over the same cable infrastructure. It should also be emphasized the high degree of compatibility of equipment from different manufacturers. For IP-based multiservice networks, a large number of standards have been developed, which are followed by most manufacturers. The main problem of voice recognition and transmission from one network to another without loss is solved using standard H.232 gateways. In addition, IP telephony solutions are highly scalable, as the number and capacity of gateways and ports can be expanded as needed.

For most users, IP telephony primarily means Internet telephony, i. voice over the Internet. The main benefit from this is known - it is cost savings on long-distance and international calls due to the low (compared to the services of traditional telephone operators) cost of the communication channel. The necessary equipment in this case is inexpensive, so the benefits are palpable. But when implementing IP-telephony technologies in an enterprise, the scale of costs is completely different, which gives reason to talk about the high cost of these solutions compared to traditional ones (the use of separate data transmission networks and telephony). Although in this case, IP-telephony also leads to a reduction in costs, in particular, with personnel and organizational reshuffles (the network is easily reconfigured) and costs for technical personnel.

The main disadvantage of IP-telephony is the lack of mechanisms for guaranteed quality of service. This is the flip side of being able to use the most common (and thus the most trouble-free) protocol. Voice traffic, unlike data, is very sensitive to delays and packet loss. If a corporate network usually has enough resources to provide users with a quality service, then when using the Internet to transmit speech packets, the bandwidth of the channels is not able to provide normal communication. Currently, technologies such as Multiprotocol Label Switching (MPLS), Resource Reservation Protocol (RSVP) and others have been developed to provide a guaranteed quality of service. However, in conditions of increasing network load with insufficient channel capacity, these technologies cannot provide high-quality voice transmission. So if we talk about Internet telephony, then its implementation requires, first of all, the emergence of broadband subscriber access networks.