Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1998-10-16
2002-04-09
Yao, Kwang B. (Department: 2664)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
Reexamination Certificate
active
06370151
ABSTRACT:
FIELD OF INVENTION
This invention relates to provisioning nodes within a telecommunications network and in particular to updating nodes with new signalling routing data for local number portability applications.
BACKGROUND TO THE INVENTION
Local Number Portability (LNP) is a new capability or service that allows end-users of telecommunications services to retain their existing telephone directory number (DN) when for example they either change from one geographic location to another or change from one service provider to another.
Local Number Portability (LNP) will likely be a service which will be ubiquitous throughout telecommunications networks. The United States is likely ahead of most other LNP interested countries in its deployment of LNP and as a consequence is experiencing first hand many of the problems associated with such a network impacting service.
It is generally realized that service providers (SP) and other interested groups will have to co-operate in defining how LNP will be implemented across a larger overall network which is made up of possibly many individually owned Service Provider networks. One such interested group are participants of the Illinois Commerce Commission (ICC) Workshop on Local Number Portability.
Of particular concern to this group is how various nodes within each of the networks will be updated with new addressing information which correctly points to where a ported subscriber can now be found within the network. This functionality generally is referred to as LNP Global Title Translation (GTT) function and must exist in a network that supports LNP to properly route signalling messages (e.g. Signalling System Number 7 (SS7) messages) that had prior to LNP, previously relied on simple six digit (NPA-NXX) GTT routing. The LNP GTT function is needed throughout the network to support services that use SS7 signalling and that are impacted by LNP. The LNP GTT function is needed when services that rely upon SS7 signalling are to be supported between networks, or whenever more than one switch supports a given NPA-NXX. The LNP GTT function may be provided by an SCP that also provides the LNP application or the function may reside elsewhere in the network.
The ICC workshop participants and industry have proposed that information about ported subscribers will be made available to Service Control Points (SCPs) supporting the LNP application from a central co-ordinator called a Number Portability Administration Center (NPAC). The terms Central LNP Administration Center and Number Portability Administration Center (NPAC) are used interchangeably in this specification. The LNP GTT function will also receive information about ported subscribers from the NPAC. The LNP SCP and LNP GTT functions are expected to be supported by a local network Service Management System (SMS) function that will provide the interface to the NPAC. However with the introduction of LNP, all LNP capable networks are going to require a ten-digit GTT node to support for example Line Information Data Base (LIDB) and Custom Local Area Signalling Services (ClASS) services as the NPA-NXX of a dialled number may not uniquely identify the targeted network element. It is also appreciated that when the NPAC broadcasts updates to all LNP capable networks there exists the potential for signalling messages to loop between networks where one network has had its GTT node(s) updated before another. If a call is encountered during this interval when network GTT nodes are not synchronized, SS7 message looping is likely to occur and will cause SS7 network congestion or possibly even network failure. The problem of non synchronized GTT nodes exists simply because GTT nodes across the network can not all be provisioned simultaneously.
Various options for dealing with looping messages have been proposed in the ICC LNP workshop final draft titled “Generic Requirements for SCP Application and GTT Function for Number Portability (Issue 0.99, Jan. 6, 1997), which is herein incorporated by reference in its entirety. Of the thirteen options discussed in Annex A of the final draft all but one address the issue of looping only after looping has started. However the third proposal suggests at a high level, a network provisioning method to prevent looping prior to it starting. However as is outlined in the ICC Final draft the participants have stated that such a method had two major flaws; first that it “will not protect against looping, when a transport (intermediate) network is used that performs GTT, without following an operational protocol”; and secondly that “this operational protocol does not currently exist”.
There are significant advantages and thus there is a need to prevent the start of looping of LNP associated signalling messages between networks which include intermediate signalling network(s).
SUMMARY OF INVENTION
The invention seeks to provide a method of provisioning LNP nodes in networks which include intermediate networks which mitigates the above known problems.
In accordance with a first aspect of the invention for a communications network comprising a plurality of service provider networks each supported by and communicating with a central administration center over separate communication links, there is provided a method of provisioning the communications network with updated signalling routing data comprising the steps of: in response to receiving a porting request to port a directory number (DN) served by a first Service Provider network to a second Service Provider network, the central administration center over respective communication links first sending updated signalling routing data reflecting the porting change toward the second Service Provider network;
in response to receiving a confirmation message that the second Service Provider network has been updated with the routing data, the central administration center over respective communication links then sending updated routing data reflecting the porting change toward at least one intermediate Service Provider network; and
in response to receiving a confirmation message that each intermediate Service Provider network has been updated with signalling routing data, the central administration center over a communication link then sending updated signalling routing data reflecting the porting change toward the first Service provider network.
In accoradance with a second aspect of the invention for a communications network comprising two or more service provider networks, a central administration center, and a local service management system for each service provider network disposed between the central administration center and the respective service provider network for providing a communication interface there between, there is provided a method of provisioning a service provider network with updated signalling routing data comprising the step of: in response to a service management system receiving a message from the central administration center comprising updated signalling routing data reflecting a porting change and a sequence number associated with the message the service management system after updating the respective service provider network with the updated signalling routing data, sending a confirmation message which includes the sequence number associated with the received message to the central administration center for tracking purposes.
Sequential provisioning of networks in accordance with the invention advantageously mitigates the problem of signalling messages looping while networks are in a non synchronized state. The method proposed works equally well where one or more intermediate networks are involved. Significant savings can be realized to service providers as little or no development is required at the network element level.
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patent: 5875242 (1999-02-01), Glaser et al.
patent: 5909682 (1999-06-01), Cowan et al.
patent: 5914798 (1999-06-01), Liu
patent: 5953338 (1999-09-01), Ma et al.
Nortel Networks Limited
Yao Kwang B.
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