MGCP

MGCP (Media Gateway Control Protocol) is a protocol used within a Voice over IP (VoIP) system. This internal protocol was primarily developed to address the demands of carrier-based IP telephone networks. MGCP is a complementary protocol for both H.323 and SIP, which was designed as an internal protocol between the Media Gateway Controller and the Media Gateway. In MGCP, an MGC primarily handles all the call processing by linking with the IP network through constant communications with an IP signaling device, for example an SIP Server or an H.323 gatekeeper.
MGCP is comprised of a Call Agent, one MG (media gateway) which performs the conversion of media signals between circuits and packets, and one SG (signaling gateway) when connected to the PSTN (Public Switched Telephone Network). MGCP is widely used between elements of a decomposed multimedia gateway. The gateway has a Call Agent, which is comprised of the call control "intelligence" and a media gateway boasting the media functions, for example conversion from TDM voice to Voice over IP.
Media Gateways feature endpoints for the Call Agent to create and manage media sessions with other multimedia endpoints. Endpoints are sources and/or sinks of data that can be physical or virtual. For creating physical endpoints, hardware installation is needed while virtual endpoint can be created using available software.
Call Agents come with the capability of creating new connections, or modify an existing connection. Generally, a media gateway is a network element which provides conversion between the data packets carried over the Internet or other packet networks and the voice signals carried by telephone lines. The Call Agent provides instructions to the endpoints to check for any events and - if there is any - create signals. The endpoints are designed in such a way as to automatically communicate changes in service state to the Call Agent. The Call Agent can audit endpoints and the connections on endpoints.

MGCP Connections

MGCP connections can be point to point or multipoint. Point to point connection can be a connection between two endpoints for transmitting data between these endpoints. Once the connection is setup between two endpoints, data transfer takes place between the endpoints. In a multipoint connection, the connection is set up between an endpoint and a multipoint session. In a multipoint connection, connections can be created over various types of bearer networks.

MGCP Architecture

MGCP came to be a much sought after application of VoIP technology because it is not involved in the frustrating work of encoding, decoding, and transferring voice signals. Though, the MGCP Call Agent works as a software switch for a VoIP network, it really does nothing more than simply direct the media gateways and signaling gateways which perform all the work. One of the main tasks in building a Call Agent is implementing the numerous possibilities in the protocol. There are various informational RFCs which may explain the expected behavior under a wide range of conditions.

In MGCP architecture, each and every command features a transaction ID, gets an acknowledgement and receives a response. This can be better understood as subscription architecture, as the Call Agent informs the media gateways and the signaling gateways as to what events it takes care of and what events it leaves unattended.
MGCP packets are generally found wrapped in UDP port 2427. Similar to what you might find in TCP protocols, MGCP datagrams are formatted with whitespace. An MGCP packer can either be a command or a response. Commands start with a four-letter verb while "responses" start with a three number response code.

What is VoIP?

VoIP (Voice over Internet Protocol) is simply the transmission of voice traffic over IP-based networks.
The Internet Protocol (IP) was originally designed for data networking. The success of IP in becoming a world standard for data networking has led to its adaption to voice networking.

The Economics of VoIP

VoIP has become popular largely because of the cost advantages to consumers over traditional telepone networks. Most Americans pay a flat monthly fee for local telephone calls and a per-minute charge for long-distance calls.

VoIP calls can be placed across the Internet. Most Internet connections are charged using a flat monthly fee structure.
Using the Internet connection for both data traffic and voice calls can allow consumers to get rid of one monthly payment. In addition, VoIP plans do not charge a per-minute fee for long distance.
For International calling, the monetary savings to the consumer from switching to VoIP technology can be enormous.

VoIP Telephones

There are three methods of connecting to a VoIP network:

• Using a VoIP telephone
• Using a "normal" telephone with a VoIP adapter
• Using a computer with speakers and a microphone

Types of VoIP Calls

VoIP telephone calls can be placed either to other VoIP devices, or to normal telephones on the PSTN (Public Switched Telephone Network).
Calls from a VoIP device to a PSTN device are commonly called "PC-to-Phone" calls, even though the VoIP device may not be a PC.
Calls from a VoIP device to another VoIP device are commonly called "PC-to-PC" calls, even though neither device may be a PC.

How does VoIP work?

VoIP or Voice Over Internet Protocol (sometimes called Internet Telephony) is touted in some circles as the technology of future. The reasoning is simple, really. VoIP is bringing possibilities to the forefront of technological thinking because the possibilities were listed as impossible just a few years ago. VoIP uses a broadband Internet connection for routing telephone calls, as opposed to conventional switching and fiberoptic alternatives. This process holds great promise in providing higher efficiency and lower cost for communication consumers. One interesting aspect of the technology is that, for the user, no large scale infrastructure is required. It's all about combining the functionality of the Internet and a conventional phone into one single service with minimal software and hardware support.

 

How Does it Work?

The most common way VoIP works is that the end user establishes a hi speed broadband connection, a router and a VoIP gateway. Instead of a standard telephone line, the router sends the telephone calls over an Internet connection. The VoIP gateway, placed somewhere in direct proximity of the connected Internet converts the analog signals into digital format, which are further broken down into smaller chunks called 'packets', before sending it over the Internet, much like the way data is transmitted to and from the computer. These packets are sent to their final destination and instructions for bringing back into an understandable form are embedded in them. It then goes through a VoIP gateway where the packets are reconverted into the original analog format utilizing a PSTN (Public Switched Telephone Network), thereby routing the call to the number the caller has dialed blending old school technology and hi tech delivery in a seamless and instantaneous way.

More Than One Way to Make a Call

Using VoIP technology, phone calls can also be made using IP phones between two computers. IP phones looks like normal standard handsets, but equipped with an RJ-45 Ethernet connector in place of the common RJ-11 connectors. These phones come with all the necessary hardware and software pre-loaded, allowing the user to directly connect to the router bringing the new user into the cost effective world of VoIP.
PC to PC calls are the easiest and most inexpensive way to make use of VoIP technology. There are many companies providing software for free or at reduced cost to encourage consumer experimentation with VoIP. When calling from a PC, all the user may need is a microphone, a suitable sound card and a reliable Internet connection. The service itself may be free of cost in many cases. The only fee the end user may have is the monthly fee for the Internet service provider and nothing additional for the actual calls made.

VoIP Features

The biggest advantage of VoIP is that the customers can make calls from anywhere in the world where a broadband Internet connection is available. The customers can take their IP phones or ATA's with them on national and international trips and still can manage to access what is essentially an individual's domestic phone line.
Then there are the softphones, which a software application that loads the VoIP services onto the desktop or laptop. Some even simulate an interface that looks like a telephone, with which you can place VoIP calls to anybody around the world, through a standard broadband connection.
Most VoIP services come with the caller id, call waiting, call transfer, repeat dialing and three-way dialing features. For additional features such as call filtering, forwarding a call, or sending calls directly to the voice mail, the service provider may assess an additional fee. Most VoIP services also allowthe user to check his/her voicemail over the web or attach messages to an e-mail that is sent to his/her PDA or PC.
Generally, the facilities and components provided by VOIP phone system suppliers and service operators may vary in significant ways. It is advisable to check the pros and cons before subscribing. Make sure that you have available technical support for the possible compatibility issues that could arise between the existing and new hardware components.

Conclusion

VoIP is still in its infancy. While it holds great promise, it has some major technical hurdles to jump, such as emergency calling, and the need for an uninterruptible power source (i.e. PC battery backup). However, as VoIP is set to become more widely available, let's hope there will be reliable solutions in place for the existing problems in the coming years. Who knows? In another five years, we may have VoIP system sans a router and the VoIP service being more common than conventional phone networks we rely on so heavily today.

How to Setup Skype

Voice over Internet Protocol, or VoIP for short, is quickly becoming recognized as one of the leading ways of communication over the Internet.
Skype is one of the most widely used programs for PC to PC calling using VoIP. To use this, you will need to have Skype installed on your computer.
You can download skype from Get Skype.
A window will open asking what you want to do with a file called SkypeSetup.exe. Click 'Run' to downloads and execute the software. A confirmation message may appear asking if you're sure you want to run this software. Just click 'Run' again.
Skype enables you to talk to anyone around the world for free. However there are a few requirements that must be met by both ends calling. This consists of a few key bits of equipment:

• A broadband Internet connection
• A microphone
• Speakers
• Skype

When the download has finished, the Skype Setup Wizard will appear and guide you through the rest of the installation. The installation is self explanitory. Accept the terms of service, and click "next". Skype should begin to install - it should take no less than 10 seconds.
Depending on what version you have downloaded, it will give you the choice to install a toolbar for Internet explorer. This is not essential, and is your own choice. After the installation wizard has finished, there should hopefully be a new icon on your desktop - a white S inside a light blue circle - This is the Skype Icon.
Upon running Skype for the first time, you will be confronted with a login dialogue box. This is where you will enter your Skype login details. If you do not have an account, just click "Don't have a Skype name" underneath the Username field.
This will cause another dialogue box to appear, with several more fields; asking you for your name, your desired Skype name, and your desired password. All this information is kept confidential. After filling these out, and accepting the terms and conditions, click next. Another dialogue box pops up asking for your current email address and your Country and city. After filling out the desired fields, hit "Sign in" and you should be signed in.
After you have successfully signed in for the first time, a "getting started" guide will appear. This guide will help you to configure your microphone and speakers so that optimum performance can be achieved. Following the on-screen instructions, you should not encounter any problems.
To test your set-up, go to the main Skype window. In the contacts section, there should be 1 contact, the Skype test call. By calling this number (double clicking) you can listen to what your microphone sounds like, and what to expect from a call.
Once you are satisfied with your sound, the set-up is complete. You can now easily access Skype and use it to make calls anytime, without having to pay a cent.

Free VoIP

Free VoIP calls are never completely free of cost. Often, the goal is not to achieve completely free calls to all destinations, but to use the VoIP operator that suits your needs best. Keeping that in mind, you will learn that most VoIP companies will let you talk for free in their own network, but will charge you for making calls outside their proprietary network.

Companies offering free VoIP calls usually offer free calls inside their own network and towards other specially selected destinations. Using this tactic users are drawn to make calls to free destinations and later purchase credits to make calls towards paid destinations.
There are several options to choose from, when it comes to selecting the right VoIP service for you.

1. The first category of VoIP services involves direct PC to PC connections, or PC to landline/mobile phone connections.
This is by far the most common way of using VoIP. It requires the use of VoIP software. Skype is one of the most popular VoIP services on the market in this category. You can initiate conversations with other Skype users free of charge. However, if you want to make calls to regular landlines or mobile phones, you will need to pay. The subscription fee for calls in North America is $30 a year. It is not a great deal of money, but it still isn't free.
Raketu, another player in the VoIP market, offers free phone calls to landlines in 42 countries and besides that, it also offers live video television. The only downside to Raketu's service is that they ask you to pay $9.95 up front in order to use their services.
It you are still looking for a cost-free VoIP service, you can use something like voipCheap that allows you to make free calls to PCs and regular phone lines. However, this service is available up to the maximum limit of 300 minutes per week, per IP address, after which you will have to pay. It includes many destinations outside USA and Canada that can be called without paying a cent, but if you want to call places not on their free calls list, you will be charged.
Google has recently come up with a new VoIP service called Google Voice, which is now being tried by many users in the US. At present, users can sign up by invitation only. Free calls and messages can be sent anywhere in the mainland US, and international calls can be made for less than half a dollar per minute.

2. The second category of VoIP services involves getting landline or mobile phone connections to be routed over the Internet.
Jajah is a good example from this category. Users of this service can make free calls to landlines and mobiles in select countries. For other select countries in Europe, Asia and South America, you can apply for landline calls.
The YouFon service routes cellular phone calls from Nokia E-Series handsets through the Internet. It lets you make free calls to other registered YouFon users for costs just around 5 dollars a month.

3. A third category of VoIP technology services involves the use of VoIP phones directly using an Internet Protocol (IP) network by connecting to it via a Wi-Fi or Ethernet network.
The ooma service is a good example from this category for users within the US. It uses peer-to-peer VoIP technology for users to make free calls within the US. The service is available for residents and up to a limit of 3000 minutes of outgoing calls. The only cost that is involved is in purchasing the device. Certain premium services are available for an extra charge.
If you manage to use services that offer good deals for what you require, you can save up to 98% from your phone bills. This means that you will need to put some time and research into it, but in the end you can achieve nearly free calls via the VoIP technology.