E164 seems set to be the next big thing in internet telephony. And our mums always told us that E numbers were bad for us!
Telephone Number Mapping (ENUM) is designed to let anyone be called anywhere regardless of different devices and applications by means of just one identifier – the plain old telephone number. While we all think VoIP is pretty cool, there’s one overarching problem: inter-domain call routing. The problem stems from communication inadequacies that prevent VoIP servers from connectiong with each other, and results in the use of a telco like BT, which results in call charges.
ENUM was developed by the Internet Engineering Task Force to solve the communication problems between VoIP systems, enabling them to find each other on the web using only a telephone number.
“ENUM allows an end user to type a number into a web browser and to access a listing of internet resources for that number, such as addresses for IP telephony, email or websites,” says Jay Daley, IT directo at Nominet. “In many ways ENUM is a medium term solution to ween us off standard telephone numbers.”
In other words, your personal phone number can also become your personal VoIP phone address. Nominet are hoping to bid for the tender of ENUM registration in the UK, and the first public E164 numbers will be avaliable next year.
Taken from .net magazine
What is ENUM?
ENUM is simply the convergence of Public Switched Telephone Networks (PSTN) to Internet Protocol (IP) Networks – in other words, the mapping of telephone numbers to domain names using a Domain Name System (DNS)-based architecture. ENUM helps to facilitate such services as Voice over IP (VoIP), and allows network elements to find services on the Internet using only a telephone number. ENUM is also the title of RFC 3761, the approved protocol document that discusses the use of DNS for the storage of E.164 numbers and the available services connected to an E.164 number.
It is also the title of RFC 2916, the approved protocol document that discusses the use of DNS for the storage of E.164 numbers and the available services connected to an E.164 number.
ENUM does not change the Numbering Plan and does not change telephony numbering or its administration in any way. ENUM will not drain already scarce numbering resources because it uses existing numbers.
How is ENUM going to work for the average end user?
What will it look like?The mechanics of using ENUM when a call is made from one person to another are virtually invisible. For instance, if one person called another and both parties were using IP phones, the call would appear as if it were being made over the regular PSTN. The calling party would designate the services its number would use, and the called party would also have specified which ENUM service they wish to have used to be contacted.
What kinds of applications could use ENUM?
The initial applications to which ENUM will be applied are Voice over IP (VoIP) and Voice Profile for Internet email (VPIM). The goal of the VoIP industry is to be able to make simple and high-quality voice calls using the internet, while the VPIM industry wants to develop voice mail systems that can exchange messages over IP networks. ENUM’s applications will most certainly reach beyond VoIP and VPIM to such services as Internet fax and Instant Messaging.
How does ENUM work?
A telephone number, once entered, is translated into an Internet address. The following steps explain the process:
- The number entered is translated into a full qualified E.164 number. (To quote an example from earlier, the number 9777 1234 in Melbourne, Australia would be +61 3 9777 1234.)
- The number is reduced to digits only. (e.g., 61397771234)
- The digits are re-ordered back to front. (e.g., 43217779316)
- Dots are placed between each digit. (e.g., 4.3.2.1.7.7.7.9.3.1.6)
- The domain e164.arpa is added to the end. (e.g., 4.3.2.1.7.7.7.9.3.0.1.6.e164.arpa)
- A DNS query is then issued on this domain.
Once the authoritative name server is found, ENUM retrieves relevant NAPTR Resource records and will perform according to the user’s registered services for that number.
What is .arpa, and why is it the top level domain for ENUM?
Why not create a new top-level domain specifically for ENUM?E164.arpa has been designated as the temporary DNS domain for use with ENUM. This designation may change as a result of ongoing discussions between the ITU, the IETF and other international organizations involved with ENUM. (In the event that the international community chooses a different ENUM domain, the structures discussed here and in IETF RFC 2916 will apply to that new designated domain.)
The .arpa domain has been designated for Internet infrastructure purposes. It is managed by the Internet Assigned Numbers Authority (IANA) in cooperation with the Internet technical community under the guidance of the Internet Architecture Board (IAB). A new top-level domain (e.g., .e164) was not created because ENUM is an infrastructure application appropriate for designation within the previously established .arpa domain. ENUM is considered appropriate as an infrastructure application because it provides a set of DNS-based resource directories, referenced by phone number, for use by various ENUM-enabled application clients (such as telephones, SIP servers and voice messaging systems).
This seams like a HUGE leap in telecommuncations to me, i’m really intrested to hear more about this in the future.
You can read more here
