Telephonic communications – Plural exchange network or interconnection – With interexchange network routing
Reexamination Certificate
2001-03-30
2003-11-11
Smith, Creighton (Department: 2642)
Telephonic communications
Plural exchange network or interconnection
With interexchange network routing
C379S221140, C379S229000
Reexamination Certificate
active
06647113
ABSTRACT:
TECHNICAL FIELD
The present invention relates to methods and systems for providing number portability in a communications network. More particularly, the present invention relates to a universal number portability routing node for providing number portability in a communications network.
BACKGROUND ART
Number portability (NP) gives telephone service subscribers the ability to change service providers without changing their directory numbers. More specifically, the generic term NP is actually representative of three basic number porting scenarios: service provider portability, which allows subscribers to change service providers without changing their phone numbers; service portability, which allows subscribers to change from one type of service to another (e.g., analog to integrated services digital network (ISDN) without changing their phone numbers; and geographic portability, which allows subscribers to move from one physical location to another without changing their phone numbers.
In the current, non-NP environment, a telephone number performs two basic functions: it identifies the customer, and it provides the network with information necessary to route a call to that customer. Number portability solutions separate these two functions, thereby providing the means for customers to keep the same directory number when changing service providers.
By separating customer identification from call routing, NP gives customers the flexibility to respond to pricing and service changes offered by rival carriers. Accordingly, it is anticipated that NP will promote local-exchange competition, which in turn will benefit all customers, as has already been the case with the long-distance market. As NP solutions are implemented, competition in the local-exchange market is expected to drive down the cost of service, encourage technological innovation, stimulate demand for telecommunications services, and boost economic growth.
A number of interim number-portability methods, such as remote call forwarding and direct inward dialing exist today. However, these methods have several disadvantages: longer call set-up times, increased potential for call blocking, continued reliance on the incumbent local exchange carrier's (LEC's) network, loss of feature functionality, as well as substantial on-going costs to the new local service provider. Among the more long-term NP solution approaches currently being offered, triggered NP technology is the most relevant to a discussion of the present invention.
Triggered NP Solutions
Triggered NP solutions, as indicated by the name, require that both the “new” and “old” service providers implement a trigger function in their respective end offices. The “old” service provider switch (often referred to as the donor switch) administers an NP trigger on the ported subscriber's directory number. When activated, this trigger causes the end office switch to formulate an NP query that is subsequently launched into the SS7 network. This NP query is ultimately delivered to an NP database that contains information related to service provider associated with the dialed number. More particularly, the NP database performs a lookup based on a portion of the called party dialed digits. A location routing number or routing number (RN) is returned by the NP database. The routing number identifies the end office of the service provider currently serving the called party. The RN value is then sent back to the end office that originated the NP query. Upon receipt of the RN containing message, the originating end office proceeds with call setup operations using the RN as a destination address for all subsequent messages associated with the call.
Shown in
FIG. 1
is an example of a telecommunications network generally indicated by reference numeral
100
that employs a triggered NP solution similar to that described above. Telecommunications network
100
includes an originating end office (EO)
110
, a recipient terminating EO
112
, a donor terminating EO
113
, a tandem switching office
114
, a signal transfer point (STP)
116
, a service control point (SCP) based NP database
118
, a calling party
120
, and a called party
122
. In this example, it is assumed that called party
122
has had local phone service ported from a service provider that owns EO
113
to a service provider that owns EO
112
. Consequently, it is implied that the service responsibility for called party
122
was transferred from the donor EO
113
to the recipient EO
112
at some point in the past. As such, EO
112
is now assumed to service called party
122
.
As such,
FIG. 1
illustrates a simplified signaling message flow sequence associated with the setup of a call from calling party
120
to called party
122
. When calling party
120
goes off-hook and dials the telephone number associated with called party
122
, originating EO
110
analyzes the dialed digits and recognizes that the dialed number falls within an exchange that contains ported subscribers. Consequently, the originating EO
110
formulates an NP query message M
1
and sends this query message to the STP
116
. Those skilled in the art of SS7 telecommunication networks will appreciate that such NP queries and responses are typically in the form of transaction capabilities application part (TCAP) protocol signaling messages. As the TCAP protocol is well known and widely employed in the communication networks presently contemplated, a detailed discussion of the TCAP signaling protocol is not included herein. A detailed discussion of SS7 TCAP signaling message structures and their associated function can be found in Signaling System #7 by Travis Russell, McGraw-Hill Publishing 1998.
Returning now to the message flow shown in
FIG. 1
, NP query message M
1
is received by STP
116
and subsequently routed to SCP-NP database node
118
as NP query message M
2
. The NP query message M
2
is processed by SCP-NP database node
118
, and an NP response message M
3
is formulated and sent back to STP
116
. It should be appreciated that NP response message M
3
contains an RN associated with recipient EO
112
, which is the EO currently servicing Called Party
122
. Tandem office
114
is particularly significant from a call setup standpoint, in that a voice trunk connection through tandem
114
will ultimately be required in order to establish a voice circuit with terminating EO
112
that is currently serving the called party
122
. NP response message M
3
is received by the STP
116
and subsequently routed to the originating EO
110
, as NP response message M
4
. The originating EO
110
processes NP response message M
4
, and uses the RN information contained therein to formulate and send a call setup message M
5
. Once again, those skilled in the art of SS7 telecommunication networks will appreciate that such call setup messages are typically of ISDN user part (ISUP) format, and as the ISUP signaling protocol is well known and widely employed in the telecommunications industry, a detailed explanation of this protocol is not provided herein. Once again, the above-mentioned text, Signaling System #7, by Travis Russell, provides a detailed explanation of the ISUP signaling protocol.
Returning to
FIG. 1
, STP
116
receives message M
5
and subsequently message transfer part (MTP) routes the message to tandem office
114
as message M
6
. Tandem office
114
examines and processes the message and formulates a message M
7
. Message M
7
is sent to STP
116
, which in turn MTP routes the message to terminating EO
112
as message M
8
. Those skilled in the art of telecommunications network operations will appreciate that additional call setup messages, not shown in
FIG. 1
, may be necessary to administer a complete a telephone call between the calling party
120
and the called party
122
. The signaling message flow shown in
FIG. 1
is intended only to generally illustrate a conventional NP translation process. As these additional signaling messages are not particularly relevant to the design and operation of
Allison Rick L.
McCann Thomas Matthew
Jenkins & Wilson & Taylor, P.A.
Smith Creighton
Tekelec
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