VoIP NEWS: March 2008

Is Your VOIP Service Secure?

For individuals, VOIP security is primarily a matter of preventing others from eavesdropping on their conversations. Some VOIP service providers offer voice security through encryption or separate data routes.

Regular precautions for transferring files should, of course, always be followed. A firewall should be in place for protecting your computer from the internet and any data or program that is downloaded should be checked for viruses.

But users should realize that VOIP hardware devices are inherently more vulnerable to attack. Some types of equipment can be made unstable or inoperable when they receive certain types of data. Some internet phones are also susceptible to data piracy, revealing private information under certain conditions.

While this probably won't be of much concern when you're calling Uncle Tim, it is a huge concern for businesses that consistently use telephone communication for discussing sensitive business information. As VOIP popularity increases, security is becoming a growing concern and is now receiving widespread attention. Security Issues

It's mainly businesses that need to be concerned with security issues related to VOIP. They are more susceptible to the Denial of Service (DOS) attacks and other forms of obnoxious hacking because many businesses operate personal gateways and other equipment for connecting to the internet.

There are several security issues associated with VOIP. Eavesdropping is an understandable fear with both regular and VOIP calls, but there are additional concerns unique to this technology. Since VOIP data is traveling across the internet just like any other kind of data, it is vulnerable to the same types of attacks. Hackers have countless software tools available to them to retrieve information being transmitted over the internet. These tools are as effective with voice data as with any other kind of data.

Another security threat is the possibility of sending viruses with VOIP data. This hasn't surfaced yet, but viruses could potentially overload VOIP networks, reduced sound quality and create delays.

VOIP isn't secure against spam either. This refers to receiving unsolicited marketing calls from companies selling their goods and services.

There are several points in the transmission of VOIP calls that hackers can use to recover information. In addition to retrieving actual conversations, they can also access critical information such as user identities and VOIP phone numbers. With this information, a hacker can place phone calls using someone else's identity.

Attackers could also record phone calls while eavesdropping on conversations and even potentially restructure voice data to create discussions that never actually existed! Log files could also be accessed and altered.

There are ways currently available that address such security issues. The first is with encryption that provides the same sort of security used in sending credit card information over a secure data connection. The second is to separate VOIP data from other internet traffic by using a Virtual Local Area Network (VLAN). Both methods can degrade call quality, but they present an alternative for sensitive calls.

VoIP Phone systems - a step above traditional phone lines

The words are; cost effective, portable, and flexible. And hey it comes with array additional new features too! No it is not our regular PSTN phone connection. The buzz word here is; VoIP phone systems.

It is the technology that transfers your voice from over the internet using specially designed call signal protocols in a much efficient manner. Efficient in terms of its low cost, the number of additional features that it offers , the convenience with which the call can be placed from anywhere at any time and for as long as you want !

The advent of the internet, bought the world closer. And it swept each one of us by our feet and today we are completely dependent on it for our day to day activities. Walking a step closer VoIP system has been developed! And it will completely revolutionarise the traditional way of making phone calls.

It’s smart, convenient, cost effective and absolutely relevant with the times we live in. How much on an effort is it, to switch on your laptop and make a call! Practically nothing! While at the same time it offers us a chance to talk for as long as we want without having to worry about the long bills!

Traditional analogue phones are a lengthy network of wires used to facilitate calling from one end to the other, and while a call takes place that particular wire system is dedicated to that one call. This is the reason; phone bills are higher on international calls. While VoIP Phones Systems work on the broadband connections. Once a call is dialed the analogue voice data is converted into small packets of digital audio data and transferred using special internet protocols from one end to the but delivered to the person in a comprehendible analogue format

Truly VoIP telephony is a step above the traditional phone lines and not far from now it would completely change the way we make long distance calls!

VoIP Communication

VoIP communication – this is the new lingo of the telecommunication industry and it promises to revolutionaries the entire scenario of today’s communication.

Popularly known as VoIP, it means voice over internet protocol. Quite literally, this is what it really does also!

A new paradigm of communication! From the time when man used the strangest of ways to communicate to one another, using sounds, clay tablets, sign language and a lot of other stuff to a present day world where two people sitting miles across can get in touch, chat or even be visible to each other at the drop of a hat! Certainly it’s been a long – long journey for us.

VoIP technology, cashes on the access to high speed internet available to common man. With the advent of broadband, several high end applications have been specially developed to render quality services and one such, is VoIP technology.

VoIP technology has the potential to upheaval the dominance of PSTN phones within no time. VoIP facilitates audio communication completely negating factors like distance, time and money!

Sounds tempting doesn’t it! But this is no mirage. VoIP doesn’t function like conventional phone lines. It is a by product of contemporary minds, who devised a way of transferring audio data in small packets via broadband internet from one network to the other , bringing down the calling charges to minimal subscription fees.

If simply put- It is the technology used and the cost factor that gives VoIP an edge over others.

The Companies offering VoIP services, sell contract packages, mostly with in-built features like free voice mails, caller ID, call waiting, call forwarding, 3 way calling, speed dialing which to the end user are free of cost. Besides the low calling rates, value added services like these make VoIP technology almost impossible to be ignored.
VoIP redefines the way we have looked at communication.

VoIP Fax

It’s only a matter of time before technology brings to us reliable faxing VoIP codec. As far as VoIP goes, the speed with which it has chiseled through our lives, sweeping us of our feet; it reinstates our faith in it and asserts that Faxing over VoIP technology will soon be a phenomenal hit too!

The basis issues over VoIP faxes are that unlike VoIP, VoIP fax functions on a different codec. While trying to send faxes through VoIP we basically have two different codec’s running, one which supports VoIP and the other which supports the fax. That’s the reason why VoIP service providers include a free additional fax line with special faxing codec’s to allow and propagate the idea of Faxing over VoIP

The reason why faxing has not picked up popularly over the VoIP technology is the basic issue of data loss or damage. Basically how VoIP technology functions is that it coverts analogue signals into digital and transfer them in the shape of small packets over a high speed broadband line.

Now when the fax tone is digitized into packets and transferred from the VoIP server these packets are often lost or damaged. Packets are lost over a VoIP call too, but this loss is still manageable as the voice can still be interpreted and understood but when it happens to the data packets of a fax, the data lost makes for a message that is non comprehendible and can really mess up the fax and result in bad fax , dropped calls or error messages.

However using fax codec, chances of proper delivery of data is greater however chances of failure increase if the number of pages increases from more than 10.

A common practice is to scan the fax copy in to a .PDF file and email it across simultaneously while using VoIP fax.

Such limitations of VoIP faxing have hampered its course of acceptability; however it’s too early to conclude the fate of this technology as it is in its nascent stage.

VoIP Call

VoIP telephony is here to revolutionaries the world of telecommunication making dedicated phone lines and long bills a thing of past. On the façade of VoIP endorsement, has been long distance calls, which have been reduced to easy calling, which is just a click away! That too with no charges replicating the bill of an over seas call...

VoIP technology speaks the lingo of the 21st century. Smart, inexpensive and efficient and backs on the internet to facilitate it – for its stands for voice over internet protocol.

Though VoIP is still a very recent phenomenon its still has managed to have swept us all by our feet. The reason that can be credited to the popularity of VoIP is the provision of making long distance calls at a very cheap rate along with n array of value added services that a VoIP subscriber receives plus the good quality of a call.

The quality of a VoIP call, though depends of several factors which should be kept in mind while setting up a VoIP system

Basically a VoIP call gets through with a broadband internet connection through which audio signals are digitalized into small packets and transferred at high speed. A VoIP call can be placed in several ways like; by using an analogue digital adaptor, broadband phone or a wireless phone.

To ensure the good quality of a call make sure

The broadband internet connection being used in, high in quality and provides good connectivity speeds. The hardware installed with a broadband connection like a modem and a splitter should be of good quality too
While connecting to the internet, the quality of the broadband phone, or the adaptor, the head sets should all be taken into consideration.
Several broadband providers today assign special call signal protocols like H.232 and SIP which are designed to facilitate VoIP traffic efficiently. These are a good alternative to the regular ISP`s for they provide services specially facilitating the requirements of VoIP users.

Virtual Private networks are a common practice amongst corporate’s who, create private networks to follow the flow of communication amongst themselves, forbidding any intrusion attempts with strong encryptions and firewalls. VPN`s ensure safe transfer of data and prohibit attempts of eavesdropping or data sniffing
Anyone who gives a serious thought to using VoIP technology should lay emphasis on the quality of the output. The quality of a call in as important as reduced bills. However it greatly depends on the steps on takes to ensure god services; like the quality of the hardware used for both broadband and VoIP and adopting special call protocols and private networks to keep the flow of calls smooth and the quality of a VoIP call supreme

VoIP Gateway

Though the output of this technology is captivating and intriguing but the fact is that VOIP technology works on a very basic principle. It is hard to believe that a technology that facilitates voice communication between two distant ends of the world easily is comprehendible.

However it is the fact.

VoIP stands for Voice over the Internet Protocol. A phone call made from one end of the world to the other, using the internet as a route instead of the dedicated phone lines is what VoIP technology does. And the flavor of internet connection used for such a purpose can be nothing else but a high speed broadband connection. The internet works in a very organized manner, with a job deployed to each member of a team, like a router, a modem a cable a gateway etc!

Off course a gateway of the virtual world sounds intriguing! While VoIP digitalizes analogue data into small packets to be transferred to the World Wide Web and vice versa, the flow of packets /data needs to be disciplined and streamed in a manner that it reaches the required destination for which routers, gateways, IP addresses are installed.

Depending on the requirement of a particular system a VoIP gateway can be installed as either a digital or analogue device within a router or a separate dedicated device. It is used to process the inflow and outflow of data from a virtual gateway. A VoIP gateway connects to the data network via Ethernet or WAN and converts the outgoing voice data received into IP packets suitable for transmission and incoming data into a stream of comprehendible data that can be used by the PBX system

VoIP gateways are special because they discipline the flow of audio data and convert them from digital to analogue and vice versa. Thereby rendering the proper channeling all data possible, this in turn makes use of VoIP really worthwhile!

VoIP Technology

VoIP technology seems to be great! But confused about how to go about it? That's the common refrain of people wanting to graduate from a dial-up connection on to VoIP. The applications of VoIP technology are so surreal, so amazing that this dilemma is not exactly uncalled for.

But before we go into the applications of VoIP, let's first understand as to what is VoIP. VoIP (voice over internet protocol) is a technological innovation allowing you to send data, audio & video concurrently over the internet, this transforms into minimal use of the available bandwidth thereby offering mind blowing transmission speeds.

VoIP has the potential to fulfill all your communication needs be it telephony, data transfer, video conferencing… your imagination is the limit. To move onto the big league, you would have to contact a VoIP service provider. These VoIP providers buy bandwidths from wholesale VoIP providers & sell it to individual customers at a premium.

Today the UK VoIP market is flush with a wide variety of VoIP providers, in order to truly enjoy VoIP you must be able to pick & choose the best provider as per your individual needs. This seems easy but it is not so, the VoIP carriers in their eagerness to corner larger chunks of the VoIP market often forgo quality & reliability.

But as it is said that 'to every problem there's a solution', you can get past this hiccup on your way to super fast communication by taking expert advice from independent VoIP link providers. These websites being independent & impartial provide you with instant links to the best VoIP carrier in your area.

This way on one hand you get a broad overview about VoIP services & on the other hand ensure effortless transition in to the VoIP arena.

VoIP for sure is the communication solution of the future, faster you join, more the advantage you get!!

How VoIP works

Before we understand the working system of VoIP technology it is essential for us to understand the importance of a high speed internet connection. As the word itself explains, internet is “inter-network”. And information that flows between various networks is known as data.

There are certain protocols and gateways that assist, an organized flow of data, between these networks and thus all sorts of data get transferred from one to the other network. It is very similar to the way we employ barriers to guide the flow of traffic!

VoIP uses a good broadband connection to connect and proceed with VoIP call. Essentially once we have a good speed broad band connection installed we can choose from any one of the three ways to place a VoIP call, though the technology behind it would always remain the same.

How VoIP functions is that once VoIP call Originates, data from that computer travels to the server of the broadband service provider with cables. Data travels in small packets through specially designed call signal protocol. These VoIP routes carry any sort of analogue audio data that a dialer inputs into the system. This data gets converted into small digital format and packed into small packets to be transferred to the destination and similarly it receives data from the other network and this is termed as VoIP Termination

VoIP functions on a global platform, it is not necessary that all the three stages of VoIP take place in the very same place. The three stages namely are VoIP call origination, VoIP Routes and VoIP Termination.

It can be broadly categorized into three tiers. Tier one operators , may have the necessary infrastructure to generate the VoIP minutes (VoIP Origination) which could even be termed as calling minutes. While Tier three operators may be in need to purchase these calling minutes to facilitate VoIP Termination. While a Tier 2 operator will be one who has the facility to route the call for it to reach from tier one operators to tier three operators while all the three operators could be located on different continents! That’s magic of VoIP!

Falling voip rates to India

From past six month there has been a rather steep cut in voip rates to India. Call rates that hovered around 8-15cents/minute are now revolving around 4-10cents per minute thanks to increased voip competition among companies and also to drop in termination charges for international calls by Indian regulator called TRAI. Some of these operators with super Indian call rates are

1)nonoh.com 0.035$/min
2)voipwise.com 0.057$/min
3)voicestick.com .060$/min
4)penntytel.com .092$/min
5)mondotalk.com .0858$/min

Here operator 1 and 2 are from famous Betamax Group as there rates change quite frequently so beware.

New Voip Offerings

India based Voip provider wroldphone.in has started offering unmited voip plans from this Diwali Festival. The service offered is a legal one with under regulation of DOT(department of Telecommunication) so there is an additional 12.5% service tax payable. Company has a range of unlimited and limited plans with incoming number of certain countries included. The Device or phone adapter itself cost 3000Rs which is on bit higher side compared to Mtnl which is offering it for Rs1500(Lifetime rental)

Unlimited plans are

1) Usa/Canada Unlimited for 1500Rs/month (Number of Limited Us states available).
2) Usa/Canada/Uk for Rs2000/month (Only London number available).
3) Usa/Canada/Uk/Australia for Rs2500/month (Only Sydney Number Available).

Limited plans with 500min/month free to 30 countries* are as follows

1) Basic Plan Usa Rs750/month includes incoming Us number.
2) Basic Plan Uk Rs950/month includes incoming Uk number.
3) Basic plan Australia Rs1150/month includes incoming Oz number.
3) Basic plan Hk/China Rs1350/month includes incoming Hk/china number.

All charges have taxes extra and free calls may not include cellphone for some countries

Voip calls to be monitored by Indian Security Agencies

All Indian Voip Providers will soon have to implement monitoring system for calls routed through them called LI. LI is the interception of telecommunications by law enforcement agencies and intelligence services keeping in view the national security.

A technology called Lawful Interception (LI) , which would allow security agencies to keep a tab on the international voice calls made for subversive activities over the Internet. LI is the interception of telecommunications by law enforcement agencies and intelligence services keeping in view the national security. Globally majority of countries have LI requirements and have adopted global LI requirements and standards developed by the European Telecommunications Standards Institute (ETSI) organization. In the USA, the Communications Assistance governs the requirements for Law Enforcement Act.

The state-owned Mahanagar Telephone Nigam Limited (MTNL) is initiating the measure by commissioning the LI system. KS Choudhari, managing director, Aks Optifibre, informed that the trials on the project has been completed. He said that security agencies are verifying and are likely to come up with the results soon. “This is a part of our VoIP contract with MTNL. But it is the first time that interceptors for data packets have been tested in India. In VoIP calls, the voice is transferred from one person to another as data packets, which makes difficult for the agencies to monitor the calls,” Choudhari said.

However, the final call remains with the government to come up with the guidelines for LI system. Bharat Sanchar Nigam Limited (BSNL) is also planning to launch VoIP services through its network.

In the expression of interest issued by the operator, it has strictly stated to tie-up with solution providers offering LI technology. Currently there are more gray market operators existing in India compared to licensed ITSPs. Once the LI system comes in place, it would give a serious blow to the illegal ITSPs offering VoIP service.

Internet Phones

VOIP phones are used all of the time now. VOIP stands for voice over IP. Which means that your voice is going over your Internet connection, to be heard over the phone to the person that you are talking to. With the way technology is moving today, before long the only phone service that will be around will be the Internet phone. With the Internet telephony close behind, it will be hard to find anyone using a regular phone line with in a few years. VOIP services first came about by using your cable line, and your cable Internet connection to get phone service to your home. Starting with companies like Vonage, the VOIP telephones really took off. Now, with all of the competition in the cable companies, you will find cheap VOIP phone service as well.

VOIP services as well as Internet phone services have really taken over the way we communicate over the telephone. So much that low rate VOIP phones are easy to come by, and if the rate is not low enough for you, just wait a while, because chances are it is still going to drop even more. If you are lucky enough to find a hosted VOIP price then you should by all means jump on it. Those that are hosted are even more affordable than the ones that are not. If you need more than one phone line connected, you may want to look into the wholesale VOIP rates. They often offer good deals for more than one line in a single place.

As you can see, Internet phones and VOIP are the wave of the future. If you are using anything other than this for your personal or business telephone line, you are in for a treat when you try VOIP. If you have not all ready, give the free Internet phone calls a try. Especially if you are paying for your long distance out of pocket. If you make more than a few calls a month, those long distance charges will add up fast, and using the Internet or VOIP for free long distance will give your pocket book a nice and much needed break. For more information on VOIP contact your local cable service provider to find out if it is available in your area. You never know when it will become available, and it is definitely something that you have to try out to believe.

Voice over Internet Protocol (VoIP) - Overview

Voice over Internet Protocol (VoIP) is a protocol optimized for the transmission of voice through the Internet or other packet switched networks. VoIP is often used abstractly to refer to the actual transmission of voice (rather than the protocol implementing it). VoIP is also known as IP Telephony, Internet telephony, Broadband telephony, Broadband Phone and Voice over Broadband. "VoIP" is pronounced voyp.

Companies providing VoIP service are commonly referred to as providers, and protocols which are used to carry voice signals over the IP network are commonly referred to as Voice over IP or VoIP protocols. They may be viewed as commercial realizations of the experimental Network Voice Protocol (1973) invented for the ARPANET providers. Some cost savings are due to utilizing a single network to carry voice and data, especially where users have existing underutilized network capacity that can carry VoIP at no additional cost. VoIP to VoIP phone calls are sometimes free, while VoIP to public switched telephone networks, PSTN, may have a cost that is borne by the VoIP user.

Voice over IP protocols carry telephony signals as digital audio, typically reduced in data rate using speech data compression techniques, encapsulated in a data packet stream over IP.

There are two types of PSTN to VoIP services: Direct Inward Dialing (DID) and access numbers. DID will connect the caller directly to the VoIP user while access numbers require the caller to input the extension number of the VoIP user.

VoIP - Functionality

VoIP can facilitate tasks and provide services that may be more difficult to implement or expensive using the more traditional PSTN. Examples include:

The ability to transmit more than one telephone call down the same broadband-connected telephone line. This can make VoIP a simple way to add an extra telephone line to a home or office.
3-way calling, call forwarding, automatic redial, and caller ID; features that traditional telecommunication companies (telcos) normally charge extra for.
Secure calls using standardized protocols (such as Secure Real-time Transport Protocol.) Most of the difficulties of creating a secure phone over traditional phone lines, like digitizing and digital transmission are already in place with VoIP. It is only necessary to encrypt and authenticate the existing data stream.
Location independence. Only an internet connection is needed to get a connection to a VoIP provider. For instance, call center agents using VoIP phones can work from anywhere with a sufficiently fast and stable Internet connection.
Integration with other services available over the Internet, including video conversation, message or data file exchange in parallel with the conversation, audio conferencing, managing address books, and passing information about whether others (e.g. friends or colleagues) are available online to interested parties.

VoIP - Implementation

Because UDP does not provide a mechanism to ensure that data packets are delivered in sequential order, or provide Quality of Service (known as QoS) guarantees, VoIP implementations face problems dealing with latency and jitter. This is especially true when satellite circuits are involved, due to long round trip propagation delay (400 milliseconds to 600 milliseconds for geostationary satellite). The receiving node must restructure IP packets that may be out of order, delayed or missing, while ensuring that the audio stream maintains a proper time consistency. This functionality is usually accomplished by means of a jitter buffer.

Another challenge is routing VoIP traffic through firewalls and address translators. Private Session Border Controllers are used along with firewalls to enable VoIP calls to and from a protected enterprise network. Skype uses a proprietary protocol to route calls through other Skype peers on the network, allowing it to traverse symmetric NATs and firewalls. Other methods to traverse firewalls involve using protocols such as STUN or ICE.

VoIP challenges:

Available bandwidth
Delay/Network Latency
Packet loss
Jitter
Echo
Security
Reliability
Pulse dialing to DTMF translation

Many VoIP providers do not translate pulse dialing from older phones to DTMF. The VoIP user may use a VoIP Pulse to Tone Converter, if needed.^{[citation needed]}

Fixed delays cannot be controlled but some delays can be minimized by marking voice packets as being delay-sensitive (see, for example, Diffserv).

The principal cause of packet loss is congestion, which can be controlled by congestion management and avoidance. Carrier VoIP networks avoid congestion by means of teletraffic engineering.

Variation in delay is called jitter. The effects of jitter can be mitigated by storing voice packets in a buffer (called a play-out buffer) upon arrival, before playing them out. This avoids a condition known as buffer underrun, in which the playout process runs out of voice data to play because the next voice packet has not yet arrived, but increases delay by the length of the buffer.

Common causes of echo include impedance mismatches in analog circuitry, and acoustic coupling of the transmit and receive signal at the receiving end.

VoIP - Reliability & Quality of service

Reliability

Conventional phones are connected directly to telephone company phone lines, which in the event of a power failure are kept functioning by back-up generators or batteries located at the telephone exchange. However, household VoIP hardware uses broadband modems and other equipment powered by household electricity, which may be subject to outages in the absence of a uninterruptible power supply or generator. Early adopters of VoIP may also be users of other phone equipment, such as PBX and cordless phone bases, that rely on power not provided by the telephone company. Even with local power still available, the broadband carrier itself may experience outages as well. While the PSTN has been matured over decades and is typically reliable, most broadband networks are less than 10 years old, and even the best are still subject to intermittent outages. Furthermore, consumer network technologies such as cable and DSL often are not subject to the same restoration service levels as the PSTN or business technologies such as T-1 connection.

Quality of service

Some broadband connections may have less than desirable quality. Where IP packets are lost or delayed at any point in the network between VoIP users, there will be a momentary drop-out of voice. This is more noticeable in highly congested networks and/or where there are long distances and/or interworking between end points. Technology has improved the reliability and voice quality over time and will continue to improve VoIP performance as time goes on.

It has been suggested to rely on the packetized nature of media in VoIP communications and transmit the stream of packets from the source phone to the destination phone simultaneously across different routes (multi-path routing). In such a way, temporary failures have less impact on the communication quality. In capillary routing it has been suggested to use at the packet level Fountain codes or particularly raptor codes for transmitting extra redundant packets making the communication more reliable.

A number of protocols have been defined to support the reporting of QoS/QoE for VoIP calls. These include RTCP XR (RFC3611), SIP RTCP Summary Reports, H.460.9 Annex B (for H.323), H.248.30 and MGCP extensions. The RFC3611 VoIP Metrics block is generated by an IP phone or gateway during a live call and contains information on packet loss rate, packet discard rate (due to jitter), packet loss/discard burst metrics (burst length/density, gap length/density), network delay, end system delay, signal / noise / echo level, MOS scores and R factors and configuration information related to the jitter buffer.

RFC3611 VoIP metrics reports are exchanged between IP endpoints on an occasional basis during a call, and an end of call message sent via SIP RTCP Summary Report or one of the other signaling protocol extensions. RFC3611 VoIP metrics reports are intended to support real time feedback related to QoS problems, the exchange of information between the endpoints for improved call quality calculation and a variety of other applications.

VoIP - Emergency calls

The nature of IP makes it difficult to locate network users geographically. Emergency calls, therefore, cannot easily be routed to a nearby call center, and are impossible on some VoIP systems. Sometimes, VoIP systems may route emergency calls to a non-emergency phone line at the intended department. In the US, at least one major police department has strongly objected to this practice as potentially endangering the public.^[4]

Moreover, in the event that the caller is unable to give an address, emergency services may be unable to locate them in any other way. Following the lead of mobile phone operators, several VoIP carriers are already implementing a technical work-around.^{[citation needed]} For instance, one large VoIP carrier requires the registration of the physical address where the VoIP line will be used. When you dial the emergency number for your country, they will route it to the appropriate local system. They also maintain their own emergency call center that will take non-routable emergency calls (made, for example, from a software based service that is not tied to any particular physical location) and then will manually route your call once learning your physical location.^{[citation needed]}

e911 is another method by which VOIP providers in the US are able to support emergency services. The e911 emergency-calling system automatically associates a physical address with the calling party's telephone number as required by the Wireless Communications and Public Safety Act of 1999 and is being successfully used by many VOIP providers to provide physical address information to emergency service operators.

VoIP - Mobile phones & Hand held Devices

Telcos and consumers have invested billions of dollars in mobile phone equipment. In developed countries, mobile phones have achieved nearly complete market penetration, and many people are giving up landlines and using mobiles exclusively. Given this situation, it is not entirely clear whether there would be a significant higher demand for VoIP among consumers until either public or community wireless networks have similar geographical coverage to cellular networks (thereby enabling mobile VoIP phones, so called WiFi phones or VoWLAN) or VoIP is implemented over 3G networks. However, "dual mode" telephone sets, which allow for the seamless handover between a cellular network and a WiFi network, are expected to help VoIP become more popular.^[7]

Phones like the NEC N900iL, and later many of the Nokia Eseries and several WiFi enabled mobile phones have SIP clients hardcoded into the firmware. Such clients operate independently of the mobile phone network unless a network operator decides to remove the client in the firmware of a heavily branded handset. Some operators such as Vodafone actively try to block VoIP traffic from their network^[8] and therefore most VoIP calls from such devices are done over WiFi.

Several WiFi only IP hardphones exist, most of them supporting either Skype or the SIP protocol. These phones are intended as a replacement for PSTN based cordless phones but can be used anywhere where WiFi internet access is available.

Another addition to hand held devices are ruggedized bar code type devices that are used in warehouses and retail environments. These type of devices rely on "inside the 4 walls" type of VoIP services that do not connect to the outside world and are solely to be used from employee to employee communications.

VoIP - Security

Many consumer VoIP solutions do not support encryption yet, although having a secure phone is much easier to implement with VoIP than traditional phone lines. As a result, it is relatively easy to eavesdrop on VoIP calls and even change their content.^[9] There are several open source solutions that facilitate sniffing of VoIP conversations. A modicum of security is afforded due to patented audio codecs that are not easily available for open source applications, however such security through obscurity has not proven effective in the long run in other fields. Some vendors also use compression to make eavesdropping more difficult. However, real security requires encryption and cryptographic authentication which are not widely available at a consumer level. The existing secure standard SRTP and the new ZRTP protocol is available on Analog Telephone Adapters(ATAs) as well as various softphones. It is possible to use IPsec to secure P2P VoIP by using opportunistic encryption. Skype does not use SRTP, but uses encryption which is transparent to the Skype provider.

The Voice VPN solution provides secure voice for enterprise VoIP networks by applying IPSec encryption to the digitized voice stream.

VoIP - Mass-market telephony

A major development starting in 2004 has been the introduction of mass-market VoIP services over broadband Internet access services, in which subscribers make and receive calls as they would over the PSTN. Full phone service VoIP phone companies provide inbound and outbound calling with Direct Inbound Dialing. Many offer unlimited calling to the U.S., and some to Canada or selected countries in Europe or Asia as well, for a flat monthly fee.

These services take a wide variety of forms which can be more or less similar to traditional POTS. At one extreme, an analog telephone adapter (ATA) may be connected to the broadband Internet connection and an existing telephone jack in order to provide service nearly indistinguishable from POTS on all the other jacks in the residence. This type of service, which is fixed to one location, is generally offered by broadband Internet providers such as cable companies and telephone companies as a cheaper flat-rate traditional phone service. Often the phrase "VoIP" is not used in selling these services, but instead the industry has marketed the phrases "Internet Phone", "Digital Phone" or "Softphone" which is aimed at typical phone users who are not necessarily tech-savvy. Typically, the provider touts the advantage of being able to keep one's existing phone number.

At the other extreme are services like Gizmo Project and Skype which rely on a software client on the computer in order to place a call over the network, where one user ID can be used on many different computers or in different locations on a laptop. In the middle lie services which also provide a telephone adapter for connecting to the broadband connection similar to the services offered by broadband providers (and in some cases also allow direct connections of SIP phones) but which are aimed at a more tech-savvy user and allow portability from location to location. One advantage of these two types of services is the ability to make and receive calls as one would at home, anywhere in the world, at no extra cost. No additional charges are incurred, as call diversion via the PSTN would, and the called party does not have to pay for the call. For example, if a subscriber with a home phone number in the U.S. or Canada calls someone else within his local calling area, it will be treated as a local call regardless of where that person is in the world. Often the user may elect to use someone else's area code as his own to minimize phone costs to a frequently called long-distance number.

For some users, the broadband phone complements, rather than replaces, a PSTN line, due to a number of inconveniences compared to traditional services. VoIP requires a broadband Internet connection and, if a telephone adapter is used, a power adapter is usually needed. In the case of a power failure, VoIP services will generally not function. Additionally, a call to the U.S. emergency services number 9-1-1 may not automatically be routed to the nearest local emergency dispatch center, and would be of no use for subscribers outside the U.S. This is potentially true for users who select a number with an area code outside their area. Some VoIP providers offer users the ability to register their address so that 9-1-1 services work as expected.

Another challenge for these services is the proper handling of outgoing calls from fax machines, TiVo/ReplayTV boxes, satellite television receivers, alarm systems, conventional modems or FAXmodems, and other similar devices that depend on access to a voice-grade telephone line for some or all of their functionality. At present, these types of calls sometimes go through without any problems, but in other cases they will not go through at all. And in some cases, this equipment can be made to work over a VoIP connection if the sending speed can be changed to a lower bits per second rate. If VoIP and cellular substitution becomes very popular, some ancillary equipment makers may be forced to redesign equipment, because it would no longer be possible to assume a conventional voice-grade telephone line would be available in almost all homes in North America and Western-Europe. The TestYourVoIP website offers a free service to test the quality of or diagnose an Internet connection by placing simulated VoIP calls from any Java-enabled Web browser, or from any phone or VoIP device capable of calling the PSTN network.

VoIP - Technical details

The two major competing standards for VoIP are the ITU standard H.323 and the IETF standard SIP. Initially H.323 was the most popular protocol, though in the "local loop" it has since been surpassed by SIP. This was primarily due to the latter's better traversal of NAT and firewalls, although recent changes introduced for H.323 have removed this advantage.^{[citation needed]}

However, in backbone voice networks where everything is under the control of the network operator or telco, H.323 is the protocol of choice. Many of the largest carriers use H.323 in their core backbones^{[citation needed]}, and the vast majority of callers have little or no idea that their POTS calls are being carried over VoIP.

Where VoIP travels through multiple providers' softswitches the concepts of Full Media Proxy and Signalling Proxy are important. In H.323, the data is made up of 3 streams of data: 1) H.225.0 Call Signaling; 2) H.245; 3) Media. So if you are in London, your provider is in Australia, and you wish to call America, then in full proxy mode all three streams will go half way around the world and the delay (up to 500-600 ms) and packet loss will be high. However in signaling proxy mode where only the signaling flows through the provider the delay will be reduced to a more user friendly 120-150 ms.

One of the key issues with all traditional VoIP protocols is the wasted bandwidth used for packet headers. Typically, to send a G.723.1 5.6 kbit/s compressed audio path requires 18 kbit/s of bandwidth based on standard sampling rates. The difference between the 5.6 kbit/s and 18 kbit/s is packet headers. There are a number of bandwidth optimization techniques used, such as silence suppression and header compression. This can typically save 35% on bandwidth usage.

VoIP trunking techniques such as TDMoIP can reduce bandwidth overhead even further by multiplexing multiple conversations that are heading to the same destination and wrapping them up inside the same packets. Because the packet header overhead is shared between many simultaneous streams, TDMoIP can offer near toll quality audio with a per-stream packet header overhead of only about 1 kbit/s.

What is VoIP?

VoIP allows you to make telephone calls using a computer network, over a data network like the Internet. VoIP converts the voice signal from your telephone into a digital signal that travels over the internet then converts it back at the other end so you can speak to anyone with a regular phone number.

VoIP can be implemented in several ways, from a software program on your computer used with a headset and microphone to adaptors used with regular analogue home phones or you can use dedicated VoIP phones which look and act like regular phones but have specially designed chips to improve call quality.

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