WO2007132108A2

WO2007132108A2 - Non-standard number routing method in a standard number routing mechanism

Info

Publication number: WO2007132108A2
Application number: PCT/FR2007/051211
Authority: WO
Inventors: Philippe Fouquart; Goar Haspekian; Linda Chong-Chauvot
Original assignee: France Telecom
Priority date: 2006-05-15
Filing date: 2007-05-03
Publication date: 2007-11-22
Also published as: EP2030418A2; WO2007132108A3

Abstract

Method for routing a call set up via a non-standard number in a network including a standard number routing mechanism (E.164), wherein, in a conversion base (DNS ENUM), a tree structure suitable for providing a standard number with at least one routing identifier (URI SIP) in the network is associated with the standard numbers. According to the invention, a specific root ('domain') is associated with at least one non-standard number category, and a specific tree structure is based on said specific root ('domain') in said conversion base (DNS ENUM), said method comprising the following steps: receiving a request to set up a call to a non-standard number, and transmitting to said routing server (SIP S-CSCF) said non-standard number with said specific root in said call setup request. The invention is useful for routing non-E.164 numbers in the IMS.

Description

ROUTING METHOD FOR NON-STANDARD NUMBERS IN A ROUTING MECHANISM FOR STANDARD NUMBERS

The present invention relates to a routing method for restoring a call to a non-standard number in a network including a routing mechanism for standard numbers.

The invention applies in particular to any end-to-end SIP signaling network whose routing relies on the ENUM technology, capable of carrying services based on non-E.164 numbering as short numbers or belonging to private numbering plans.

An example of networks concerned by the invention is illustrated by the networks built on a particular SiP architecture known as IMS ("IP Multimedia Subsystem").

In general, networks based on IMS architectures apply routing mechanisms different from those traditionally used in switched telephone networks (PSTNs). These IMS mechanisms are essentially based on a particular function of the Domain Name System (DNS), called ENUM, which, in this context, makes it possible to translate a telephone number into a SIP identifier called URI (Uniform Resource Identifier). ") Natively mutable in networks using the SIP protocol, which is the case of IMS architectures. These standardized routing mechanisms are now applicable to standard numbers that are part of the international numbering plan called "E.164" with reference to the ITU Recommendation which defines it. These international E.164 telephone numbers are now used in client-server architectures, such as directories for example, as universal key to access a set of identifiers associated with these numbers. The ENUM function, described in the IETF RFC 3761 standard, makes it possible to know, by querying the DNS system using a standard telephone number in accordance with the international standard ITU E.164, the possible multimedia identifiers for joining a correspondent. . The result of an ENUM request can be one or more URIs with their processing order and their preference. These URIs are then used to reference resources or services associated with the E.164 standard number such as, for example, an e-mail address, a web page, a directory service, fixed or mobile reference numbers, or an alias of Voice over IP, videophone or instant messaging for SiP or H.323 protocols.

A call established using an E.164 standard number in an IMS network is performed according to the following routing mechanism.

In NMS, following a request to establish a call to an E.164 international format number, an S-CSCF ("Call Session Control Function") server, having determined that the called number complies with the standard E.164, converts this number into an expression, a domain name, serving as a basis for querying the ENUM function, which will respond to the request with at least one URI. For example, from the E.164 standard number "+33123456789" the S-CSCF server builds the expression "9.8.7.6.5.4.3.2.1.3.3" to concatenate it to another "root" domain name ( a predefined root) and obtain the full name "9.8.7.6.5.4.3.2.1.3.3.root". For example, RFC 3761 defines the root value as "e164.arpa". Once concatenated, the fully qualified domain name thus formed is "9.8.7.6.5.4.3.2.1.e164.arpa". Note that the IMS also allows you to set your own root as a parameter of the SIP server.

The root domain name "e164.arpa" thus represents the root of a tree structure of the ENUM translation database associating at least one URI identifier with the expression provided by the S-CSCF server. In response to the request, the ENUM function searches in the translation database whose root is "e164.arpa" or URI identifiers corresponding to the expression received when (s) exist (s). A URI identifier returned to the SIP server by the ENUM function is for example of the type "sip: dupond@provider.com" where "provider.com" is a domain name. The call setup request is then routed to another SIP server associated with the domain "provider.com". This IMS SIP server which is the entry point to the network associated with the domain name "provider.com" is generally called I-CSCF (I for "Interrogating").

Thus, in an IMS architecture, the routing logic is as follows: any IMS subscriber has an entry in the ENUM database, a number that is not present in this database must not be routed to an IMS server such as N-CSCF, but to a destination outside the IMS network. However, ENUM does not consider hosting non-standard numbers belonging to a numbering plan other than the E.164 international numbering plan. Therefore, when a non-standard number is used to address a destination in the IMS network, it is not present in the ENUM tree, and the routing can not be performed according to the mechanism just described. but requires a special mechanism dedicated to this new dialing configuration.

This dedicated mechanism may consist of complicating the number analysis methods at the level of the SIP servers S-CSCF or defining a default route, for example imposing the transit via the switched network RTC.

Specifically, when a calling terminal that belongs to the network

SIP makes a call setup request using a short, nonstandard number, the S-CSCF server detects that this short number can not be present in the ENUM database and that, therefore, the destination of the call does not belong to the SIP network, In this case, the S-CSCF server refrains from making a request to the ENUM function and directly directs the call to the switched network RTC. The call is then processed by complex routing mechanisms known to RTC networks that need not be further described here. In summary, the current mechanisms in IMS architectures are subject to a constraint that limits their use to only standard numbers in the E.164 international format, because they base the DNS ENUM database tree on a predefined single root, in General the root "e164.arpa" mentioned above. It is therefore impossible to use it to analyze non-standard E.164 numbers such as short numbers of the subscriber dial plan or a private numbering plan, for example, and to send this type of destination without an ad-hoc mechanism. in an IMS network.

Also, the technical problem to be solved by the object of the present invention is to propose a routing method for establishing a call to a non-standard number in a network including a routing mechanism for standard numbers associating, in a translation base, standard numbers a tree structure capable of providing a standard number at least one routing identifier in the network, which would treat non-standard numbers as easily as standard numbers, avoiding the use of a complex ad-hoc mechanism, for example a routing to an external network, such as the RTC network cited in the solution example presented above.

The solution to the technical problem posed consists, according to the invention, in that, a specific root ("domain") being associated with at least one category of non-standard numbers, and a specific tree structure being constructed on said specific root (" domain ") in said translation database (DNS ENUM), the method comprises the following steps:

- receive a call setup request to a non-standard number, and

- To transmit to a server (SIP S-CSCF) routing, said non-standard number accompanied by said specific root, in said call setup request.

Thus, the method according to the invention consists in providing, via the signaling used when establishing the call to a non-standard number, the specific root associated with this category of non-standard numbers. The invention involves enriching the translation base, such as the ENUM database, of complementary tree structures constructed from specific roots, a specific root being associated with a given category of non-standard numbers. For example, to private short numbers of the internal numbering plan to an XYZ ₁ company constituting a nonstandard number category, we can associate in the translation database a specific root such as "XYZ" or "xyz.com", just as the root "e164.arpa" is associated with E.164 standard numbers.

It is then sufficient to accompany the private short number composed of the corresponding specific root for a SIP server of the S-CSCF type to find that the corresponding non-standard number category is known from the ENUM base and form a request to this base for obtain a URI identifier, according to a mechanism equivalent to that implemented for standard numbers. According to one aspect of the invention, said specific root is transmitted as a given value to the context parameter ("phone-context") defined in the IETF RFC 3966 standard.

The invention also relates to a translation base intended to associate standard numbers with a tree structure capable of supplying a standard number with a routing identifier in a network, which is remarkable in that said translation database also contains at least one associated tree structure. to non-standard numbers.

The invention also relates to a terminal requesting a non-standard number in a network including a routing mechanism for standard numbers associating standard numbers with a tree structure capable of supplying a standard number with at least one routing identifier in the network. remarkable in that said terminal is capable of providing, during a call sent to a non-standard number, said non-standard number accompanied by a specific root of a specific tree structure associated with a non-standard number category to which belongs said non-standard number.

The invention also relates to a call server intended to receive a call establishment request from a terminal in a network including a routing mechanism for standard numbers associating standard numbers with a tree structure capable of providing a number standard at least one routing identifier in the network, wherein a specific root ("domain") is associated with at least one non-standard number category, and a specific tree structure being constructed on said specific root ("domain") in said database (DNS

ENUM), said call server comprises the means for:

- receive a call setup request to a non-standard number, and

transmitting to a server (SIP S-CSCF) routing said non-standard number accompanied by said specific root, in said call setup request.

The invention further relates to a routing server for establishing calls in a network including a call number routing mechanism associating, in a translation database, at least one category of call numbers with a root a tree structure capable of providing a call number with at least one routing identifier in the network, characterized in that, a specific root ("domain") being associated with at least one non-standard number category, and a specific tree structure being built on said specific root

("Domain") in said translation database (DNS ENUM), said routing server comprises means for:

receiving said non-standard number accompanied by said specific root in said call setup request;

- checking the presence of said root in the translation database;

in case of positive verification, transmit said call number to the translation database, and

- Receive from the translation database said routing identifier (SIP URI). In addition, the invention relates to a computer program product downloadable from a communication network and / or stored on a computer readable medium and / or executable by a microprocessor, characterized in that it comprises program code instructions for carrying out the process according to the invention. The invention finally relates to a computer program product downloadable from a communication network and / or stored on a computer readable medium and / or executable by a microprocessor, notable in that it includes program code instructions for executing the operations performed by the routing server according to the invention.

The following description with reference to the accompanying drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be achieved.

FIG. 1 is a diagram illustrating the exchanges between an SIP server S-CSCF and a DNS database ENUM. FIG. 2 represents a routing algorithm associated with the diagram of FIG. 1.

In IMS networks, non-E.164-compliant numbers must be conveyed in call setup messages with a parameter defining the context in which they may be interpreted. This context parameter, for example the "phone-context" parameter as defined in the IETF RFC 3966 standard, makes it possible to specify the perimeter within which the number conveyed must be interpreted and outside which it is not valid. This context parameter can be valuated by different types of entities during the call, in particular the call terminal itself or a server initiating the call.

The method according to the invention constructs for non-standard numbers not belonging to the E.164 plane the ENUM DNS request associated with a given category of non-standard numbers from the name of a specific root assigned to that category in the context parameter, for example "phone-context" of the URI present in the Request-URI field of the call setup message. For this request to succeed, a corresponding specific tree structure based on this root is previously created in the ENUM database where non-standard numbers of the intended category are associated with SIP URIs. We can take the example of private numbers of the XVZ internal numbering plan whose associated domain name is "xyz.com". In an exemplary application of the invention, during a SIP call to the short number 1234 of the internal numbering plan of the company XVZ whose holder is called "abc", the number 1234 is accompanied in the INVITE SIP message of a parameter "phone-context = xyz.com" at the calling terminal, or a call server intended to receive the SIP call of the terminal, and transmitted to an SIP server S-CSCF, which determines that the specific root "xyz.com" is known from the ENUM database. The SIP server S-CSCF then formulates a request from the expression "4.3.2.1. xyz.com ". The ENUM database performs a search in a specific tree structure whose root is "xyz.com" and sends back to the S-CSCF server the URI identifier "sip: abc@xyz.com". The call setup request is then routed through the standard PIMS routing mechanisms to an I-CSCF server associated with the "xyz.com" domain.

Similarly, calls to short numbers internal to an operator can be initiated by accompanying the requested number, for example "3123", with a context parameter such as "phone-context = numerocourt.operateur.com". On receipt of such a call setup request, the SIP server having determined that the requested number is not an E.164 number queries the DNS ENUM database having previously concatenated the sequence "3.2.1.3. numerocourt.operateur.com ". The ENUM server is therefore interrogated on the domain "3.2.1.3. numerocourt.operateur.com "and responds with a routing identifier value that has been previously provided, for example" s ^' φ: service @ operator. com ».

This mechanism is illustrated by Figures 1 and 2.

Of course, as indicated more particularly in FIG. 2, the choice of a context parameter value equal to the specific root domain name of a DNS tree in which the non-standard numbers E.164 will be registered has no impact on the processing of E.164 standard numbers, which can continue to be translated on the reference root "e164.aφa" or another, if this was the choice of implementation. As shown in Figure 2, in case of failure, ie if the call number is neither a standard number E.164, nor a non-standard number, short or private, for example, implemented in the ENUM database in accordance with the invention, it is then necessary to use an ad hoc mechanism, such as the routing to the switched network RTC cited above.

In general, by applying an ENUM request from the root domain name carried by the "phone-context" parameter, any entity can then easily route calls to non-standard E.164 numbers in I ¹ IMS, without the need for a specific number analysis.

Since each non-E.164 number carried in I ¹ IMS is accompanied by the only information necessary for its own routing, the routing of the calls is automated. Therefore, for all types of numbers requested, E.164 and not E.164, the routing of calls in IMS networks relies entirely on the DNS infrastructure.

In summary, the process according to the invention consists in:

- use the domain name carried by the context parameter associated with non-E.164 numbers as the root domain name of a specific DNS tree of the ENUM type, parallel to that used for E.164 numbers,

- create this new specific tree in which will be stored all non-standard numbers interpretable in the same dial plan. For each context of number interpretation, such as private plan, special service, subscriber dial plan, etc., a new specific DNS tree can be created in which non-standard numbers can be associated with a SIP URI, naturally routable in SIP networks. Each new tree will derive from a proper root specific to the dialing context designated by the domain name carried by the "phone-context" parameter.

Another embodiment is to create a dedicated SIP parameter to convey the specific ENUM root information to be used, for example "enum-root". The parameter "phone-context" always present would then simply give an indication of the context while the new parameter would carry the specific ENUM root domain name associated with this context. The SIP call setup request could then convey for example "phone-context = + 33" and "enum-root = xyz.com". This other embodiment would allow:

- not to impose a formalism on the "phone-context" parameter, the use of a domain name being done to the detriment of a value of the type "+ <digits>",

to overrule the procedures that could be linked to the "phone-context" parameter already implemented in certain equipment and incompatible with the format domain name or the semantics induced by the first embodiment of the invention described above.

Claims

A routing method for restoring a call to a non-standard number in a network including a routing mechanism for standard numbers (E.164) associating, in a translational DNS (ENUM) database, with standard numbers a tree structure capable of supplying a standard number with at least one routing identifier (SIP URI) in the network, characterized in that a specific root ("domain") is associated with at least one non-standard number category, and a tree structure specific being built on said specific root ("domain") in said translation database (DNS ENUM), said method comprises the following steps

- to receive an application to establish a call to a non-standard number, and

2. Method according to claim 1, characterized in that said specific root is transmitted in the form of a given value to the context parameter ("phone-context") defined in the IETF RFC 3966 standard.

3. Method according to claim 1, characterized in that said specific root is a value given to a dedicated parameter ("enum-root").

4. Method according to any one of claims 1 to 3, characterized in that said standard numbers are numbers in accordance with the international numbering E.164.

5. Method according to claim 4, characterized in that said translation database is provided by the ENUM function of the DNS system.

6. Method according to claim 5, characterized in that said specific root is a domain name ("domain").

7. Method according to any one of claims 1 to 6, characterized in that said network is based on an IMS architecture.

8. Method according to claim 7, characterized in that said routing identifier is a SIP URI.

9. Translation base (DNS ENUM) for associating with standard numbers (E.164) a tree structure capable of supplying a standard number with a routing identifier (URI SIP) in a network, characterized in that said base of translation also contains at least one tree structure associated with non-standard numbers.

Terminal requesting a non-standard number in a network including a routing mechanism for standard numbers (E.164) associating standard numbers with a tree structure capable of providing a standard number with at least one routing identifier (SIP URI). in the network, characterized in that said terminal is able to provide, during a call sent to a non-standard number, said non-standard number accompanied by a specific root of a specific tree structure associated with a non-standard number category. standard to which belongs the non-standard number.

1 1. Call server for receiving a call setup request from a terminal in a network including a routing mechanism for standard numbers (E.164) associating, in an ENUM database (translation), with the standard numbers a tree structure capable of providing a standard number with at least one routing identifier (SIP URI) in the network, characterized in that a specific root ("domain") is associated with at least one non-standard number category, and a specific tree structure being built on said specific root ("domain") in said translation database (DNS ENUM), said call server comprises the means for:

receiving a call setup request to a non-standard number; and transmitting to a server (SIP S-CSCF) routing said non-standard number accompanied by said specific root in said call setup request.

12. Routing server (SIP S-CSCF) for establishing calls in a network including a routing mechanism for standard numbers (E.164) associating, in a translational DNS (ENUM) database, with the standard numbers a tree structure adapted to provide a standard number at least one routing identifier (SIP URI) in the network, characterized in that a specific root ("domain") is associated with at least one non-standard number category, and a specific tree structure being built on said specific root ("domain") in said translation database (DNS ENUM), said routing server comprises means for: - receiving said non-standard number accompanied by said specific root, in said request for call establishment;

- checking the presence of said root in the translation database;

in the case of positive verification, transmit said call number to the translation base, and receive from said translation base said routing identifier (SIP URI).

13. Computer program product downloadable from a communication network and / or stored on a computer readable medium and / or executable by a microprocessor, characterized in that it comprises program code instructions for the execution of the method according to claims 1 to 8.

14. Computer program product downloadable from a communication network and / or stored on a computer readable medium and / or executable by a microprocessor, characterized in that it comprises program code instructions for the execution of operations performed by the routing server according to claim 12.