VOIP Internet Phone Center

Although using different technology and approach, some of the same component concepts that make up the PSTN also create voice over IP networks. There are three major pieces to a VOIP network.

-voice over IP networks
-media gateways/signalling controllers
-media gateways

Media gateways are responsible for call origination, call detection, analog-to-digital conversion of voice, and creation of voice packets (CODEC functions).

Typically, each conversation (call) is a single IP session transported by a Real-time Transport Protocol (RTP) that runs over UDP.Their features and services can include some or all of the following.
-Network access servers that can attach a modem to a telephone circuit and provide data access to the Internet.
-Business media gateways that provide a traditional digital PBX interface or an integrated soft PBX interface to a voice over IP network.
-Access media gateways that provide a traditional analog or digital PBX interface to a voice over IP network. Examples of residential gateways include cable modem/cable set-top boxes, xDSL devices, and broadband wireless devices.
-Trunking gateways that interface between the telephone network and a voice over IP network.
-Access media gateways that provide a traditional analog or digital PBX interface to a voice over IP network.
-Discreet IP telephones units.

-Network access servers that can attach a modem to a telephone circuit and provide data access to the Internet.
-Business media gateways that provide a traditional digital PBX interface or an integrated soft PBX interface to a voice over IP network.
-Access media gateways that provide a traditional analog or digital PBX interface to a voice over IP network. Examples of residential gateways include cable modem/cable set-top boxes, xDSL devices, and broadband wireless devices.
-Trunking gateways that interface between the telephone network and a voice over IP network.
-Access media gateways that provide a traditional analog or digital PBX interface to a voice over IP network.
-Discreet IP telephones units.
Media Gateway Controllers
The media gateway controller has the responsibility for some or all of the call signaling coordination, phone number translations, host lookup, resource management, and signaling gateway services to the PSTN (SS7 gateway). Media gateway controllers could be considered similar to that of H.323 gatekeepers. Media gateway controllers house the signaling and control services that coordinate the media gateway functions.The amount of functionality is based on the particular voice over IP enabling products used.

In a scalable VoIP network, you can breakup the role of a controller into signaling gateway controller and media gateway controller. You could use a signaling gateway controller to directly connect to the SS7 network, while also interfacing to voice over IP networks elements. For calls that originate and terminate within the domain of the voice over IP network, only a media gateway controller might be needed to complete calls.

The services of these devices are defined by the protocols and software they are running. There are several protocols and implementations that any number of vendors could deploy. Knowing the details of how the devices use their suite of protocols is important to designing the IP backbone that is to service the voice over IP elements.

Depending on the voice over IP protocols used, this system as a whole is sometimes referred to as a softswitch architecture.

Jim Francisto
best voip provider

Thanks to caller ID we can instantly see the land line or cell phone number shown on the caller ID screen. Nonetheless often we cannot always identify the cellular or land line number displayed.

Not more then a few years ago you were an easy target for such calls, but at the present time we have a way to to find out precisely who is the person behind the number by taking advantage of cell phone number reverse search services.

Online assistance directories offering cell phone number reverse search can come in handy for solving many similar problems. Everyone who has ever been a target of these sort of calls is familiar with how frustrating it is when caller hangs up. It is impossible for you to know if the person who called you dialed the wrong phone number, if it was some kind of an emergency and should you be worried about it, or if the caller simply has nothing better to do in the middle of the night.

Another situation that can entice a person to conduct a cell phone number reverse lookup is to find out who owns a certain number. Everybody who has ever discovered a strange number in their cell phone, laundry, telephone book, or around the house is going to find cell phone number reverse search incredibly beneficial.

It happens frequently, and more than ever when jotting down a number in a rush. How else would a person guess who could be the owner of that number without the help of a reverse number lookup?

Directories offering telephone number reverse search are very valuable, especially in the situations mentioned before. Very often it can be quite tricky to work out precisely who a number belongs to without making use of this type of technology which has not always been readily available to people who needed such information.

So given that telephone number reverse look up is now readily available, why not use the information that it has to offer? This is the time when information is accessible with merely a click of a button, and information that was until now complicated to find is now offered to anyone.

So to sum up, next time you notice a number on your caller ID, in your wallet or on your phone invoice and you have no idea who owns it, don’t fret. Simply utilize your MAC or PC and carry out a cell phone number reverse search. When you have the information you needed, you will be grateful for the benefits reverse search technology has provided us with.

Voip sends your phone call through the Internet
A Voip router is a very small device that is used by the majority of Voip users to make calls over the Internet. One of the main differences between traditional telephones and Voip is that traditional phone signals are analogue and are sent physically through wires. Voice over IP sends a digital signal and sends it as packet data through the Internet. Therefore, for a person to continue to use the same phone that they have always used for voice over IP calls, they need a device to convert their analogue signal to a digital signal. This is what the Voip router is designed to do.

Voip technology is advancing rapidly
Digital phones allow Voip users to plug directly into their Internet connection or their computer to make telephone calls, thus eliminating the need for a router. Furthermore, it will only be a matter of time before our homes are fully networked for Internet access in every room, thus making IP calls easier and the delivery of other services that will soon be provided through the Internet.

Make your move to Voip as soon as possible
Voip is the telephony of the future. This is indicated by how the large traditional phone companies have all converted over to this technology. What you can expect with a switch to Voip is much lower telephone bills and the closest communication with long-distance family members and loved ones than you have ever known. When they say that the world is getting smaller, it can now truly be seen.

Voip is easy
Although many people fear new technologies or are slow to convert over to a new way of doing things because they are so comfortable with the old, Voip calls is something that you should switch over to without hesitation. Of course, the Voip company that you choose to work with is your decision. Just understand that any switch to Voip is better than not switching. For those that hate new devices and new gadgets, a Voip router makes everything so simple and easy to use. Basically, a voice over IP router will have a socket for you to plug your phone into and another socket for you to plug your internet connection in to. Once you plug in those two things, you will never have to think about your VoIP router again. Now, that is simplicity!

Jim Francisto

Accelerator products can help enterprises a lot in addressing the performance requirements of all enterprise applications including voip. First, Accelerators change the economics of wide area networking by squeezing an average of 100% - 400% more bandwidth with peaks of 1000% depending on traffic mix. This frees up link bandwidth to support high quality voice over IP services - and it does it without expensive WAN upgrades.

It is also worthy to note that Accelerators do not actually use lossy compression schemes that might degrade voice quality and they add less than one millisecond of latency. In fact, the Accelerator’s compression actually reduces end-to-end latency by reducing serialization delays on WAN links. For example, it takes 125 ms to serialize a 1,000 byte packet on a 64 kbps link, but if an Accelerator increases the effective bandwidth by 4X to 256 kbps, the serialization delay is reduced by a factor of four to 31 ms. The following formula can be used to calculate the serialization delay for any combination of packet size and link speed:

Packet Size (in bytes) x 8 / Speed (in kbps) = Serialization Delay (in ms)

In addition to freeing up the bandwidth normally consumed by data applications, Accelerators are able to reduce WAN bandwidth requirements for different voip codecs. In fact, tests have shown that Accelerators reduced G.711 bandwidth requirements by 20% and G.729 by 70%. As a result, WAN links can carry more simultaneous voice calls and the performance of other applications may also be improved.

Accelerators solve increased jitter and latency caused by large data packets over slow WAN links by fragmenting large data packets and injecting voip packets at regular intervals. This feature allows voip and data to co-exist even on branch office WAN links. For example, normally, a voice over IP packet “stuck” behind a 1,500 byte packet on a 64kbps lin will be delayed by 188ms.

Using the Accelerator’s packet fragmentation will result in the data packet being reduced in size (accelerated - say from 1500 bytes to 500b bytes) and then fragmented into smaller data packets (say - 2 packets of 250 bytes each). In this case, the latency for the voip packet will go down from 188 ms to 31ms! In addition to increasing WAN capacity for both data and voip while reducing latency and jitter, Accelerators also manage WAN bandwidth to ensure that critical applications like voip get the bandwidth they need.

Accelerators include an Instant QoS feature that prioritizes application access to WAN bandwidth. Without such priorization, the additional effective bandwidth provided by Accelerators could be consumed by aggressive, non-critical applications such as file sharing. Accelerator’s AppView feature provides graphical visibility for all application traffic sharing a link. AppView can be used to monitor WAN utilization and to plan future capacity requirements.

And finally, ip accelerators have a set of data integrity features that are designed to stop the packet loss that can degrade voice quality. A flow control mechanism reduces packet loss caused by link congestion and a packet recovery feature ensures that any lost packets are transparently recovered at the link level before they can cause voice quality problems.

Jim Francisto

As companies have grown, and moved from just using telephones to email and web based systems, so the humble telephone directory has needed to expand and grow. In the 1980s telecoms companies developed the X.500 specification, which is a collection of protocols to create and distribute a directory of information.

X.500 directory services were accessed via the X.500 Directory Access Protocol (DAP) which used the Open Systems Interconnect (OSI) protocol stack. As companies [spi]began|started[/spin] to implement TCP/IP networks, many found the complexity of managing a large OSI/DAP network too much. The Lightweight Directory Access Protocol (LDAP) was developed to access X.500 directory servers over TCP/IP.

An LDAP server uses the concept of an organisational hierarchy to organise information, which can include usernames, telephone numbers, office locations, photos, and more. This directory structure can closely match a company’s structure, making LDAP directories an obvious fit for replacing an organisation’s phonebook. The initial X.500 specification was deliberately designed with this scalable organisation of information in mind, which is one of the main factors behind the success of LDAP.

With the development of Voice Over IP (VOIP) technologies an entire organisation’s information can be held within LDAP, allowing access from email clients, instant messaging applications, and HR systems. Even products like Microsoft’s Active Directory utilise LDAP and X.500 directory structures. LDAP’s flexibility makes it an useful of any company infrastructure.