VoIP
Description:
Voice over Internet Protocol, also called VoIP (pronounced "vee-oh-eye-pee" [1] or "voyp"), IP Telephony, Internet telephony, and Broadband Phone is the routing of voice conversations over the Internet or through any other IP-based network.
Protocols 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.
Voice over IP traffic can be deployed on any IP network, including those lacking a connection to the rest of the Internet, for instance on a local area network.
Enablers:
Cost In general, phone service via VoIP is free or costs less than equivalent service from traditional sources but similar to alternative PSTN (Public Switched Telephone Network) service providers. Some cost savings are due to using a single network to carry voice and data, especially where users have existing under-utilized network capacity they can use for VoIP at no additional cost. VoIP to VoIP phone calls on any provider are typically free, whilst VoIP to PSTN calls generally costs the VoIP user.
There are two types of PSTN to VoIP services: DID (Direct Inward Dialing) and access numbers. DID will connect the caller directly to the VoIP user while access numbers requires the caller to input the extension number of the VoIP user. Access numbers are usually charged as a local call to the caller and free to the VoIP user while DID usually has a monthly fee. There are also DID that are free to the VoIP user but is chargeable to the caller.
Functionality VoIP can facilitate tasks that may be more difficult to achieve using traditional phone networks:
Incoming phone calls can be automatically routed to your VoIP phone, regardless of where you are connected to the network. Take your VoIP phone with you on a trip, and wherever you connect to the Internet, you can receive incoming calls. Free phone numbers for use with VoIP are available in the USA, UK and other countries from organizations such as VoIP User. Call center agents using VoIP phones can work from anywhere with a sufficiently fast Internet connection. Many VoIP packages include PSTN features that most telcos normally charge extra for, or may be unavailable from your local telco, such as 3-way calling, call forwarding, automatic redial, etc.
Mobility VoIP allows users to travel anywhere in the world and still make and receive phone calls:
Subscribers of phone-line replacement services can make and receive local phone calls regardless of their location. For example, if a user has a New York City phone number and is traveling in Europe and someone calls the phone number, it will ring in Europe. Conversely, if a call is made from Europe to New York City, it will be treated as a local call. Of course, there must be a connection to the Internet e.g. WiFi to make all of this possible. Users of Instant Messenger based VoIP services can also travel anywhere in the world and make and receive phone calls. VoIP phones can integrate 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.
Inhibitors:
High transistion cost. Deployement Issues: Transistioning or direct replacement IPv6 is not backwards compatible: IPv4 applications cannot work with IPv6. Major patching effort. Lack of IPv6 applications in general. Transistion phase is needed: Either applications get rewritten, or we translate/tunnel different IP protocols through each other. [IPv4 over IPv6 or IPv4 over IPv6].
Paradigms:
IPv4 era: Limited amount of online users thus a limited amount of IP-addresses, mostly allocated to US. IPv6 era: Enormous boom in online users, and new (mobile) networks demand for more and more IP-addresses. Backwards compatability should be solved by workarounds like tunneling or translation.
Experts:
Timing:
When the demand for new IP-addresses is high enough to force the industry to invest in IPv6 infrastructure. But before that happens IPv6 will be stimulated by many IPv6 networks that communicate over the web via IPv4 (tunneling/translation).
Web Resources:
[1] IPv6 Benefits and Issues
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