What is IP telephony?

IP (Internet Protocol) telephony is an aspect of communication that uses the Internet to exchange voice, fax, and other types of information over IP-based networks. In fact, it is a technology-specific term that meets the needs of today's smart communications.

Traditionally, this has been done over the public switched telephone network (PSTN) and has relied on dedicated circuit-switched connections. However, IP telephony simplifies it and transfers information in the form of packets over the Internet or LAN (local area network), bypassing the problems of the PSTN. Simply put, it is a single network infrastructure that provides both voice and data solutions.

Benefits of IP telephony

1. Unified Communications (UC) network

IP telephony is known for its reliable voice communications over local area networks. Due to its reliability, it is also considered a unified communications (UC) model with various valuable features such as presence support, web conferencing, video and audio conferencing, and free calls over the data network. This unified communications package will drive the growth of organizations without significant investment.

2. Smart solution for mobility and connectivity

Undoubtedly, IP telephony improves communication for everyone, even remote workers. Today, you don't need to carry your prepaid business phone with you wherever you go. IP telephony allows remote workers to access their network using cell phones anywhere, provided they have an Internet connection. In fact, this improves connectivity at other enterprise stations, in cities or even countries. Consequently, these mobility solutions improve the quality of the employee experience. You can learn more about how this mobile solution is changing the employee experience.

3. Easy to use softphone technology

Softphone technology is analogous to a teleworker solution. In fact, a softphone is a software service that you can easily download to your laptop or desktop computer without the need for any hardware device. And then you can call all over the world from your laptop. Once you subscribe to this service, you will have access to all UC (unified communications) services. There is a rich set of features and benefits built into softphone technology that offer excellent digital calling capabilities. Learn more about softphone technology here and see the difference.

4. Multifunctional communication aspect

No one can deny that IP telephony is revolutionizing the way we communicate with its rich feature set. One is that IP phones can do much more than just make calls. Others can range from teleconferencing capabilities, programmable buttons, auto attendant functionality, voice mail to email transcription, multi-site connectivity over a data network, Unified Messaging, Call Waiting and Caller ID, and more. IP phones are bigger than TDM systems. Here you can learn more about the advantages of IP telephony over TDM.

5. Easy to install and configure

You don't need to be a professional or technician to install and configure IP phones. It doesn't have the complexity of programming, proprietary software, graphical user interface and other such confusing stuff. Just a person who knows about networks can install and configure it without any problem.

6. Ease of scaling

IP phones are not limited to a limited number of physical phone connections. This gives you complete flexibility when you need to add a new IP phone. Businesses can easily add or remove a new or existing IP phone to / from the router.

7. Cost savings through increased productivity

For the first time, workers can communicate over one or more main phone lines inside and outside the organization. In addition, businesses do not have to pay the price charged by telephone companies because analogue telephone lines are no longer needed. Consequently, the cost is reduced. In addition, IP telephony supports a wide range of applications that help employees complete their tasks faster, more efficiently and more efficiently.

IP and VoIP

IP (Internet Protocol) and VoIP (Voice over Internet Protocol) - people often use these terms interchangeably. But there is a difference. However, it is so subtle, but it is so.

Anyway, VoIP is a subset of IP. This means that VoIP is based on sending only voice traffic over an IP (Internet Protocol) network, while IP is based on the exchange of voice, fax, and other types of data traffic.

In digital form, all elements of IP telephony use digitized voice, which is transmitted in the form of IP packets over an IP network (mainly LAN). In addition, VoIP focuses on digitizing analog voice signals (analog to digital conversion) and converting to binary numbers for transmission over IP.

Thus, in a broader sense, IP telephony is a completely complete concept, while VoIP telephony is a voice transmission mode to implement this concept. As for, for example, an IP telephony system or IP-PBX (Private Branch Exchange) containing its own VoIP and standards (SIP, H.323) in combination with other aspects such as CRM, etc.

IP telephony scheme

How do IP phones work?

Basically, IP phones work by scanning and detecting an analog human speech signal and converting it into digital signals. These digital signals are then transmitted over a wideband line in the form of data. In simple terms, IP phones work by taking telephone conversations and routing them through the IP phone system through a network cable to the network, then from there, and then to the Internet connection.

Instead, we can say that IP phones use "Internet protocols" to connect and communicate digitally over the Internet. With this system, you can choose this technology instead of traditional telephone systems to improve communication. Just use an Internet connection, appropriate hardware (phone system) and applications that make communication more efficient.

Or, simply, instead of the traditional telephone line and telephone network, the system uses the Internet protocol and local area network to transfer calls and other information over your office network and the network of the telecom operator. And the same protocol and network are also used by computer systems, devices, and printers. This makes it relatively efficient. You and your employees only need to use and maintain one intranet for all communications.

IP telephony deployment models

You need to choose the best deployment model that suits your needs and your network. Only then will your IP telephony be in order. Because once you choose the right model, it will support both the present and future growth of voice and data. Here you can view the different IP telephony deployment models and choose the one that suits your needs.

During deployment, you can face many obstacles. But choosing a reliable model will instantly fix these problems. After all, choosing today's stable model will accelerate the delivery of voice and other data inside and outside your enterprise more efficiently.

Features of IP telephony

1. HD voice quality

This IP telephony attribute allows users to enjoy HD quality that results in seamless communications, audio masking integration to eliminate unnecessary noise, and access to group call history, filtering and exporting, and recording management.

2. Lots of extension options

Built-in Automatic Call Routing allows users to automatically route calls to one or more preprogrammed destinations. In addition, calls will be safely and automatically redirected to the next available extension. And a voicemail box is associated with each line or extension.

3. One number

This is one of the most flexible features, allowing you to call the same number from different phones. In addition, the mobile phone number is hidden, so the caller will not be able to determine your location.

There are a number of features of IP telephony in the telecommunications sector. The key is to make the most of this feature, which will bring added value to your business. Here you can familiarize yourself with other necessary IP telephony functions and find out what you need.

IP telephony protocols

1. Session Initiation Protocol (SIP)

It is a signaling protocol that is used to establish a "session" between two or more participants, change that session, and finally end that session. And the actual data transfer is done by the Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) at layer 5 of the OSI model.

This protocol is text-based and is very similar to the HTTP protocol. And these text messages, together with the request-response mechanism, make troubleshooting easier.

2. H.323

Like SIP, this list also takes into account H.323, which has the same functionality as SIP. This protocol is also responsible for initiating, modifying, and terminating a session. It is the one in the ITU-T set of standards that constructs a set of protocols for providing audiovisual communications over a computer network. It is actually a binary protocol that transmits voice or video over a network.

3. Real Time Transport Protocol (RTP)

RTP protocol, defined in RFC 1889, is a standard packet format for transmitting audio / video over the Internet. This protocol is widely used in communications and entertainment systems that include streaming media such as telephony, television services, video conferencing applications, and web-based push-to-talk functions.

In fact, RTP works hand in hand with RTCP (Real Time Transport Control Protocol). RTP transmits media streams, while RTCP monitors transmission statistics, QoS and helps in synchronizing the various streams. Second, RTP comes from the even numbered ports, while RTCP uses the higher odd numbered port.

4. Real Time Transport Control Protocol (RTCP)

This protocol is defined in RFC 3550 and works in conjunction with RTP (as described in RTP). This protocol is responsible for sending control packets to the participants in a particular call. In fact, the main task is to provide QoS feedback provided by RTP.

RTP comes from the even numbered ports, while RTCP comes from the next higher odd numbered port. RTCP conveys information and statistics such as jitter, octet and packet counts, and round trip times. A specific application uses this data to control QoS parameters and make choices such as using a separate codec.

5. Secure Real Time Transport Protocol (SRTP)

SRTP is one of the security protocols used for WebRTC technology and was published as RFC 3711 by the IETF (Internet Engineering Task Force) in 2004.

Basically, it is an extended component of RTP (Real Time Transport Protocol) that adds security elements, message authentication, privacy, and replay protection, mainly for VoIP communications. In addition, it uses encryption and authentication to mitigate the risks of attacks such as denial of service.

6. Session Description Protocol (SDP)

Published by the IETF as RFC 4566, SDP defines a specific standard for defining parameters used when exchanging media (mainly streaming media) between two endpoints. In fact, it is wrapped exclusively in another protocol with a widely used application, being inside SIP within most applications.

This implies that SDP is a declaration of its specifications and capabilities for the media endpoint to receive. So, a separate declaration can indicate:

What IP address will receive the incoming media stream
What port number serves the incoming media stream
What category of media the endpoint expects to receive (usually audio)
In what protocol the endpoint expects to exchange data (usually RTP)
What compression encoding can the endpoint decode (codec)

And much more... In a typical session initiation process, two endpoints participate in the session. Each endpoint broadcasts SDP to the other endpoint to communicate its characteristics and capabilities. In fact, SDP itself does not send any media, but is limited to negotiating a well-suited set of media exchange parameters. Even media streams are also handled by some different protocols and channels.

Common IP telephony problems

1. The need for an energy source

IP telephony devices or phones operate on and receive power from a wall outlet. Thus, there may be a greater chance of failure during local power outages until emergency power is available. In this case, you must have a reliable backup power supply to avoid Internet telephony problems.

2. Voice compression (codec)

If your call quality is up-to-date and you are faced with a voice communication problem, then there is a problem with the codec settings. This technology actually compresses the sound so that it can be transmitted more efficiently. In this case, you can either - follow scientific methods with different codecs and find out which one is the best (contact your IT department for this); or - if you are experiencing audio distortion during the busiest times, then there must be a bandwidth issue. You need bandwidth to test it with your IT department. or the internet service needs to be updated.

3. End of Internet Service Provider

If, unfortunately, you often encounter problems, you need to immediately contact your Internet provider and check their services. This may be possible - the ISP may have periods of high latency in the connection; or - they send your data over a public network instead of a private one. Check with your ISP and assess if they are experiencing service outages or any network issues. In this case, it's time for your problem to be resolved by your ISP or switch to a new ISP.

The list doesn't end there. Users can face many IP telephony errors at any time, but they can be fixed in no time. Although IP telephony systems are connected to the Internet directly or indirectly, depending on the bandwidth, associated problems will arise. In addition, problems with voice and / or other data transmission are included in the list of common problems. Here you can find several common preventable IP telephony problems and solve them easily.

Frequently asked Questions

What is the difference between IP-PBX and EPABX?
EPABX (Electronic Private Automatic Branch Exchange) or PABX (Private Automatic Branch Exchange) or PBX (Private Branch Exchange) is a private telephone network that serves business communications in enterprises and organizations. But IP-PBX works digitally and has a rich set of features, including VoIP.

Therefore, IP-PBX and EAPBX basically have the same functionality. However, EPABX uses analog technology to a certain level. Thus, companies prefer the IP-PBX to the EPABX primarily to avoid the complexity of the wires. If you want to know the benefits of using an IP-PBX, you can read here - IP-PBX vs EPABX.

What is the difference between IP telephony and PSTN?
Technically, IP telephony is related to packet switching, while the PSTN (Public Switched Telephone Network) is related to circuit switching.

In simple terms, with PSTN there is a direct connection between two communicating voice parties through a dedicated channel. And this circuit is completely reserved for one pin. And with IP telephony, several packets go through one communication line. And the voice packet of one or more conversations may or may not follow the same path as other packets carry data, video, etc.

We can determine that PSTN is something traditional, requiring a huge amount of resources, and IP telephony is a modern system that simplifies everything thanks to the Internet.

Can IP telephony systems be connected to traditional public telephones?
Yes it is. But this requires a dedicated voice gateway that converts IP packets from IP phone systems to TDM (time division multiplexing) voice for sending over the traditional PSTN. So the action takes place.

What is the difference between PRI and SIP Trunking?
SIP (Session Initiated Protocol) and PRI (Primary Rate Interface) are two different technologies that connect your business to the PSTN. And yet the “path” is different. SIP trunks are used to send voice and data over the Internet (virtually), while PIR trunks are used to send voice and data over a dedicated physical line.

In addition, SIP requires little or no hardware investment to deploy, while PRI requires complex setup, maintenance, and upfront hardware investment. However, you find it difficult to make a decision? PRI vs SIP Trunking is here to help you.

Where can you use your IP phones?
You can use your IP phones wherever there is an internet connection. They do not rely on any common location. You can easily disconnect your IP phone, move it to another location and reconnect it as long as your line (phone number or extension) and associated settings remain the same.

Do you need specific phones?
Yes, there are special handsets that are specially designed for hassle-free IP communication over the network. These telephone systems are available from most international telephony product manufacturers such as Mitel, Panasonic, Counterpath, Aastra, Cisco, GrandStream, etc.

How will it affect the voice quality?
“Voice” is the main component of telephony, and therefore a minor issue has a large impact on the entire conversation. Thus, you have to make sure that there will be no latency, no jitter, no bandwidth problems, no compression problems, etc. To solve such problems, you can use modern technologies that must synchronize with the communication. lines, routers, bandwidth usage, etc. - to avoid any clutter during a call.

Since the violation of the voice leads to a decrease in productivity, and this is not needed by anyone. To overcome this problem, high bandwidth lines are used together with powerful routing equipment (for example, routers and fairly large switches). Thus, they are expensive. To resolve this issue, prioritize voice packets over other data. The price will drop and you will have a better experience on the other end.

Is IP telephony a cost-effective solution?
The use of IP telephony technology is seen as a medium to long term business. And, according to studies, packet-switched networks, which are used for voice communications, are more cost-effective than circuit-switched networks. The reason is that a circuit switched network uses the entire communication line for only one conversation, compared to a packet switched network. Consequently, the cost will automatically rise.

In addition, when the communication line runs between different places, cities, states or countries, using a private network is safe and much more economical than using a public network.

In short, IP telephony is a much smarter and more viable option than legacy telephony solutions.