Portability of non-geographic telephone numbers of intelligent network services

A telecommunications network (10) comprises a set of telephone service operator domains (20), including domains (20A-20C) having intelligent network-type services having non-geographic telephone numbers. A call-originating domain (20G) accesses a non-geographic service number database (30G) to obtain address information concerning the domain which currently handles the called service (90). The address information obtained from the non-geographic service number database includes the address a node in the domain which handles the service, e.g., the address of a gateway node (GW), and optionally the addresses of a service switching point (SSP), a service control function (SCF), and a service data function (SDF) which handles the called service (90). When changing telephone service operators (e.g., changing to a new domain), the non-geographic service number database is updated to reflect the change. Access of the database and usage of the addresses obtained therefrom in the routing message permit the service (90) to retain the same directory number when changing telephone service operators.

BACKGROUND 
1. Field of Invention 
This invention pertains to telecommunications systems, and particularly to 
the routing of calls through a telecommunications system to an intelligent 
network service having a non-geographical telephone number. 
2. Related Art and Other Considerations 
A telecommunications network typically includes a number of physical nodes, 
often referred to as local exchanges, to which subscribers are connected. 
The local exchanges are generally connected in the telecommunications 
network by other physical nodes, known as transit exchanges. 
To simply the routing of calls through the network and to have a good 
structure of a telephone numbering plan, each local exchange is allocated 
one or more unique exchange number groups. The telephone number of a 
subscriber typically includes both an exchange number group (typically a 
10,000 number block) for the exchange to which a subscriber is connected, 
and a number in that group which is peculiar to the subscriber. For 
example, a subscriber having a telephone number"881-1657" is connected to 
a local exchange having an exchange number group "881", and within that 
group the subscriber has a subscriber number of "1657". The subscriber's 
telephone number is published or otherwise circulated as his directory 
telephone number e.g., in a telephone directory or book. 
The foregoing is an example of telephone numbers which are geographical, 
i.e., for which there is a defined relationship between the telephone 
number and a geographical area served by the exchange to which the 
subscriber is connected. For other telephone numbers, referred to as 
"non-geographical telephone numbers", no geographical relationship exist. 
Non-geographical telephone numbers include those associated with services 
such as services provided by intelligent networks, for example toll-free 
numbers ("800" in the United States), Freephone, Universal Access Numbers, 
Personal Numbers, Universal Personal Telecommunications (UPT), Virtual 
Private Networks (VPNs), International Virtual Private Networks (IVPNs), 
etc. Such intelligent network (IN)-type services are controlled and 
executed by a service control point (SCP). For each IN service, data used 
for the SCP's performance of the IN service typically resides in and is 
retrieved from a service data function (SDF), which can either be 
collocated with the SCP or remotely located at a service data point (SDP). 
With the advent of pro-competitive regulations for the telephone industry, 
telecommunications subscribers will be entreated to change telephone 
service providers. In some instances, a change of telephone service 
providers has traditionally involved a change of directory telephone 
number for the subscriber, since differing telephone service providers 
have differing blocks of numbers in a telephone numbering plan. Changing a 
directory telephone number undesirably occasions expense and effort for 
the subscriber. For example, the subscriber incurs expense in providing 
notice of the new directory number to potential callers (friends and 
business contacts). If such notice is not provided or retained by the 
potential callers, calls may not be placed to the relocated subscriber. 
Loss of calls to a ported subscriber can result in loss of social or 
business opportunity. 
For clarity, what is commonly referred to as a telephone service provider, 
e.g., a telephone company, will hereinafter be referred to as a telephone 
service operator (TSO). Unless in context of TSO or otherwise stated, the 
word "service" hereinafter refers to an intelligent network type of 
service as is offered by a subscriber e.g., to other subscribers. 
If subscribers could retain their original telephone numbers, decisions 
regarding telephone service operator networks could be based on other 
factors, such as competitive pricing, quality of service, and service 
features, for example. Providers of IN services having non-geographical 
telephone numbers could avail themselves of opportunities for changes of 
telephone service operators if the providers were assured that their 
original non-geographical telephone numbers could be retained after the 
change to a new telephone service operator. 
Traditional telephone call routing principles pose a problem for retention 
of telephone numbers upon a change of telephone service operator. In this 
regard, a common way of routing a call through a telecommunications 
network to a final destination is to use the directory telephone number of 
the called party (e.g., the called subscriber), i.e., the "1-800-xxx-nnnn" 
for a toll free call. In particular, in traditional routing, the called 
party's directory telephone number occupies an address signal field of an 
ISUP parameter known as the "Called Party Number" parameter ("CdPN"), with 
the "Called Party Number" parameter ("CdPN") being a routing or address 
message utilized for routing purposes. 
What is needed therefore, and an object of the present invention, is an 
efficient way of permitting a provider of a non-geographic telephone 
number to retain the non-geographic telephone number when the service 
provider changes telephone service operators. 
SUMMARY 
A telecommunications network comprises a set of telephone service operator 
domains, including domains having intelligent network-type services having 
non-geographic telephone numbers. A call-originating domain accesses a 
non-geographic service number database to obtain address information 
concerning the domain which currently handles the called service. The 
address information obtained from the non-geographic service number 
database includes the address of a node in the domain which handles the 
service, e.g., a gateway node (GW), and optionally the addresses of a 
service switching point (SSP), a service control function (SCF), and a 
service data function (SDF) which handles the called service. When 
changing telephone service operators (e.g., changing to a new domain), the 
non-geographic service number database is updated to reflect the change. 
Access of the database and usage of the addresses obtained therefrom in 
the routing message permit the service to retain the same directory number 
when changing telephone service operators. 
Some embodiments particularly show routing e.g., to a service control 
function (SCF) of the telephone service operator network of the recipient 
IN service from a service switching function (SSF) of the same telephone 
service operator network. Other embodiments, by contrast, show e.g., 
examples of routing to a service control function (SCF) of the telephone 
service operator network of the recipient IN service from a signal 
switching function outside of the telephone service operator network of 
the recipient service (e.g., from the caller's telephone service operator 
network). In conjunction with such routing, a database outside of the 
telephone service operator network of the recipient service is queried to 
obtain address information, including the address of the SSP to be 
utilized in the outside network and the address of the SCF which handles 
the service. The database can be consulted at various by various nodes, 
including a local exchange node, a transit node, or a SSP, for example.

DETAILED DESCRIPTION OF THE DRAWINGS 
In the following description, for purposes of explanation and not 
limitation, specific details are set forth such as particular 
architectures, interfaces, techniques, etc. in order to provide a thorough 
understanding of the present invention. However, it will be apparent to 
those skilled in the art that the present invention may be practiced in 
other embodiments that depart from these specific details. In other 
instances, detailed descriptions of well known devices, circuits, and 
methods are omitted so as not to obscure the description of the present 
invention with unnecessary detail. 
FIG. 1 shows a telecommunications system or network 10 according to an 
embodiment of the invention. Network 10 includes a set of telephone 
service operator domains 20A-20C and 20G. Three of the domains 
(particularly domains 20A-20C) cater to subscribers which provide 
intelligent network-type services having non-geographic telephone numbers; 
domain 20G serves subscribers with geographical telephone numbers. In the 
illustrated embodiment, domain 20G can be of a network type such as a 
public switched telephone network (PSTN) or integrated services digital 
network (ISDN), for example. In one mode of the invention, some of the 
domains 20 are served by differing telephone service operators, e.g., 
different telecommunications operating companies. 
Geographical domain 20G includes at least one local exchange 22G. Local 
exchange 22G is connected to a plurality of fixed subscriber stations, 
only one of which (subscriber 24) is shown in FIG. 1. Local exchange 22G 
is connected via transit exchange 23G to a gateway exchange or gateway 
node 26G. Gateway node 26G is connected to a database 30G. Database 30G 
is, in turn, connected (e.g., for updating and maintenance purposes) to an 
operator management system (SMS) 32G. 
Domains 20A-20C each have respective gateway nodes 26A-26C. Each gateway 
node 26A-26C and 26G is connected to a gateway node of at least one other 
domain, all gateways nodes being interconnected in the example shown in 
FIG. 1. 
Each gateway node 26 serves as an interface to external domains 20 for one 
or more service switching points (SSPs) 40 which belong to the domain. 
Each SSP 40 is a node which can communicate with service control functions 
(SCFs) 50, hereinafter described, by means of TCAP and SCCP protocols 
(hereinafter described). Although each of domains 20A-20C have a plurality 
of SSPs, for each domain only two such SSPs are labeled. For example, 
domain 20A has SSPs 40A-1 and 40A-2; domain 20B has SSPs 40B-1 and 40B-2, 
and so forth. Each gateway node 26 is connected to the SSPs 40 in its 
domain. 
Domains 20A-20C include both service control functions (SCFs) 50 and 
Service Data Functions (SDFs) 60. The SCFs 50 control processing of e.g., 
intelligent network (IN) services and custom service requests. When 
implemented in a standalone physical mode, an SCF is called a sence 
control port (SCP) The SDFs 60 are service data functions in which data 
for an IN-type service is stored and from which the IN service data is 
retrieved and used by the SCP for performance of the IN service. Although 
not specifically shown in the drawings, an SDF can be collocated with the 
SCF at an SCP or can be remote from the SCP. A remotely located standalone 
SDF resides at a service data point (SDP). Usage of SDF herein is intended 
to cover both cases of the IN service data being located at the SCP or at 
an SDP. 
Domains 20A-20C have a plurality (n number) of SCFs 50 and a plurality (k 
number) of SDFs 60, i.e., SCFs 50A-1 through 50A-n and SDFs 60A-1 through 
60A-k (k usually being less than n). SCFs 50 of a domain 20 are connected 
to each of the SSPs 40 and SDFs 60 of that domain (although this need not 
necessarily always be the case). In addition, at least one of the SCFs 50 
of a domain 20 is connected to database 30 for that domain. Each SDF 60 of 
a domain is connected to the operator management system 32 of the domain. 
Although all domains herein are illustrated as having the same number of 
constituent elements, e.g., n number of SCFs and k number of SDFs, the 
number of such elements per domain typically varies. 
Each of domains 20A-20C further includes respective databases 30A-30C. In 
each domain 20, database 30 is connected to gateway node 26 and (depending 
on how much information is received at gateway node 26) to one of the SSPs 
40 and to one of the SCFs 50. 
Databases 30A-30C are also connected to and maintained by operator 
management systems (SMS) 32A-32C, respectively. In each of domains 
20A-20C, operator management systems 32A-32C are connected to each of the 
SDFs 60. Operator management systems 32-32C of domains 20A-20C 
respectively are also connected to and supervised by a master operator 
management system 32M. 
Databases 30 are subscriber location servers which are augmented with 
additional intelligence and accordingly are known and denominated (e.g., 
in U.S. patent application Ser. No. 08/733,930, filed Oct. 18, 1996, 
incorporated herein by reference) as a network number and address 
portability servers (NAPS). Databases 30 include information which 
facilitates number portability for many types of subscribers in their 
respective domains, including subscribers which offer intelligent 
network-type services which have non-geographical telephone numbers. 
Without overlooking the broader use of the databases 30, for convenience 
herein, the databases 30 will sometimes be referred to as non-geographical 
service number databases 30 to emphasize the aspects thereof pertinent to 
the present invention. 
As will become more apparent below, the domains 20A-20C comprise an 
operator changeability domain for non-geographic service numbers. In the 
operator changeability domain, a subscriber with a non-geographical 
telephone number can change telephone service operators, e.g., change from 
one of the domains to another, e.g., change from domain 20A to domain 20C, 
and still maintain the same "directory" number for the intelligent 
network-type of service provided by the subscriber. 
Although domains 20A-20C show primarily equipment useful for supporting 
non-geographic intelligent network-type services for the sake of 
illustrating the present invention, it should be understood that domains 
20A-20C are not so limited and that varieties of other types of telephone 
services can also be provided. 
Communications and signaling occurs between domains 20 of FIG. 1 and their 
components. Telecommunications models have been created for standardized 
descriptions of different cases of information transfer in networks such 
as network 10 of FIG. 1. One such model is the Open System Interconnection 
(OSI) model, which is structured in well-defined and specified layers 
which are each completely independent of the others. Like the OSI model, 
the CCITT Signaling System No. 7 is also structured in layers. The first 
such layer is the physical level, which is the interface to the 
information bearer, the signaling network. The first layer converts the 
zeros and ones of a frame into pulses of the right size and shape and 
transmits them over a line. The second layer concerns fault handling, and 
has functions for separating messages, fault detection and correction, 
detection of signaling link faults, etc. The third layer concerns 
addressing and message handling (e.g., distribution and routing), and 
contains functions for ensuring that the message gets to the correct 
exchange, and functions for checking the network and maintaining 
transmission capabilities. The fourth layer is the user part, and is 
designed so that several different users can use the same signaling 
network. 
CCITT Signaling System No. 7 includes a number of functional parts, 
including a Message Transfer Part (MTP) and a number of different user 
parts. As shown in FIG. 11, the Message Transfer Part (MTP) resides in the 
first three layers. The Message Transfer Part (MTP) serves as a common 
transport system for reliable transfer of signaling messages between 
signaling points and is independent of the content of each User Part 
message. Thus, the responsibility of the MTP is to convey signaling 
messages from one User Part to another User Part in a reliable way. Each 
user part contains the functions and procedures which are particular to a 
certain type of user of the signaling system. Examples of user parts are 
the Telephone User Part (TUP), the Data User Part (DUP), the ISDN User 
Part (ISUP), and the Mobile Telephone User Part (MTUP). 
In the OSI layer organization, CCITT 1984 introduced a Signaling Connection 
Control Part (SCCP) which provides additional functions to the Message 
Transfer Part (MTP) and which is situated above MTP in the OSI layering 
scheme [see FIG. 11]. The combination of MTP and SCCP is called the 
Network Service Part (NSP). The Network Service Part (NSP) meets the 
requirements for Layer 3 services as defined in the OSI Reference Model, 
CCITT Recommendation X.200. The SCCP is described in CCITT Recommendation 
Q.711Q.716. The SCCP makes it possible to transfer both circuit related 
and non-circuit related signaling and user information between exchanges 
and specialized centers in telecommunications networks via a CCITT No. 7 
network. 
Layers 4-6 of the OSI model of FIG. 11 include the Intermediate Service 
Part (ISP). The Intermediate Service Part (ISP) is an element of the 
transaction capabilities which supports the Transaction Capabilities 
Application Part (TCAP) for connection-oriented messages. The Transaction 
Capabilities Application Part (TCAP) resides in layer 7 of the OSI model. 
Also provided in layer 7, residing above the Transaction Capabilities 
Application Part (TCAP), is the Intelligent Network Application Protocol 
(INAP). 
FIG. 2 illustrates actions involved when subscriber 24 in geographical 
domain 20G places a call to a non-geographical telephone number for an 
intelligent network-type (IN) service. In the particular example of FIG. 
2, the call is placed to an IN service which is performed by SCF 50A-1 
using data stored in SDF 60A-1 of domain 20A. In view of the called 
service's data being stored in SDF 60A-1, for simplification the service 
is depicted by reference numeral 90 as residing in SDF 60A-1 (although SCF 
50A-1 actually performs the service). 
Action 2-1 shows subscriber 24 dialing the directory number ("Servno") of 
the non-geographical IN service and the dialed directory number being 
routed to local exchange 22G. Action 2--2 shows local exchange 22G sending 
a routing message to transit exchange 23G. In action 2--2, the directory 
number ("Servno") of the non-geographical service 90 is included in an 
address signal field of a routing message such as an ISUP called party 
parameter (CdPN). The routing message is, in turn, relayed by transit 
exchange 23G to gateway node 26G as indicated by action 2-3. In FIG. 2, 
the expression CdPN{Servno} is meant to indicate that the CdPN parameter 
includes, in its address signal field, the directory number (Servno) 
dialed by subscriber 24 in an effort to reach service 90. 
FIG. 12 shows the format of a called party parameter (CdPN) of the ITU-T 
Rec. Q.763 standard, an industry standard. The called party parameter 
(CdPN) is utilized to route calls between exchanges of a 
telecommunications system. The CdPN format of FIG. 12 includes a seven bit 
Nature of Address Indicator ("NAI") in its first byte; a Number Plan 
Indicator ("NAPI") in bits 5-7 of its second byte; and an Address Signal 
Field ("ASF") in its last n-3 bytes. The Number Plan Indicator ("NAPI") is 
a field that has one of 8 different values, and which indicates to what 
type of plan the called subscriber subscribes (e.g., ISDN or not). The 
Nature of Address Indicator ("NAI") is an ISUP parameter having one of 128 
values, many of which are spare (i.e., not yet assigned). The NAI is 
conventionally employed to indicate such things as whether the number is a 
national number, and international number, etc. The Address Signal Field 
("ASF") has n-2 number of four bit nibbles, each nibble representing an 
address signal. The most significant address signal is sent first, 
subsequent address signals are sent in successive 4-bit nibbles. 
Gateway node 26G receives the routing message from transit exchange 23G 
and, as indicated by action 2-4, sends a query with CdPN{Servno} to 
non-geographical service number database 30G. In the mode shown in FIG. 2, 
non-geographical service number database 30G uses the Servno value in the 
CdPN parameter to determine that the dialed service 90 is currently served 
by gateway node 26A. Then, at action 2-5, non-geographical service number 
database 30F returns to gateway node 26G a CdPN parameter that now 
includes both the address of gateway node 26A (GW26.sub.AADDR) and the 
Servno of the called non-geographical service 90, i.e., CdPN 
{GW26.sub.AADDR, Servno}. 
At action 2-6 gateway node 26G formulates and sends to gateway 26A an 
initial routing message (IAM) which includes the CdPN parameter having the 
values returned by non-geographical service number database 30G, 
particularly GW26A.sub.ADDR and Servno. Then, at action 2-7, gateway 26A 
uses the Servno value to query database 30A to determine which of the SSPs 
in the domain, i.e., SSPs 40A-1, 40A-2, is to be utilized to reach service 
90. Action 2-8 shows database 30A returning to gateway 26A an address for 
the appropriate SSP, for example the address of SSP 40A-1. 
In action 2-9, the call is routed to the appropriate SSP whose address was 
returned from database 30A in action 2-8. 
At action 2-10 SSP 40A-1 queries database 30A to obtain a "Global Title" to 
be used for communicating to the SCF which supports service 90. The Global 
Title or "GT" is an address in the SCCP part (see FIG. 11). Action 2-11 
shows the Global Title being returned by database 30A to SSP 40A-1, in 
particular a Global Title indicative of SCF 50A-1 for the present example 
involving service 90. Action 2-12 then shows the InitialDP being sent to 
SCF 50A-1. The InitialDP is a query on ITU-T & ETSI standardized INAP 
protocol versions 1 & 2, and is the first operation sent from a service 
switching point to a service control point when an intelligence ("IN") 
trigger is detected in the service switching point. 
At action 2-13, SCF 50A-1 queries database 30A to get the Global Title to 
the service data point (SDP) corresponding to the service data point at 
which resides the service data function (SDF) which holds the data for 
service 90. The Global Title to SDF 60A-1 is returned to SCF 50A-1 in 
action 2-14. Knowing the Global Title of SDF 60A-1, at action 2-15 SCF 
50A-1 fetches the data pertaining to service 90 which is stored at SDF 
60A-1. The data pertaining to service 90 which is stored at SDF 60A-1 is 
returned to SCF 50A-1 by action 2-16. SCF 50A-1 then uses that data to 
route the call to the equipment which provides service 90. 
FIG. 3 shows telecommunications system or network 10' according to another 
embodiment of the invention. Network 10' of FIG. 3 differs from network 10 
of FIG. 1 only in that, in domain 20G, transit exchange 23G is connected 
to and has access to database 30G. In view of such connection, after 
action 2--2 transit exchange 23G queries database 30G as indicated by 
action 2-3(3). At action 2-4(3), database 30G returns to transit exchange 
23G a CdPN parameter that includes both the address of gateway node 26A 
(GW26A.sub.ADDR) and the Servno of the called non-geographical service 90, 
i.e., CdPN{GW26A.sub.ADDR, Servno}. This CdPN parameter is then relayed to 
gateway node 26G by action 2-5(3). Thereafter, the call is routed to 
domain 20A and the actions in domain 20A above described with respect to 
FIG. 2 occur so that the data for service 90 can be obtained from SDF 
60A-1. 
FIG. 4 shows telecommunications system or network 10" according to yet 
another embodiment of the invention. Network 10' of FIG. 4 differs from 
network 10 of FIG. 1 only in that, in domain 20G, local exchange 22G is 
connected to and has access to database 30G. In view of such connection, 
after action 2-1 local exchange 22G queries database 30G as indicated by 
action 2--2(4). At action 2-3(4), database 30G returns to local exchange 
23G a CdPN parameter that includes both the address of gateway node 26A 
(GW26A.sub.ADDR) and the Servno of the called non-geographical service 90, 
i.e., CdPN{GW26A.sub.ADDR, Servno}. This CdPN parameter is then relayed to 
transit exchange 23G at action 2-4(4), and then relayed to gateway node 
26G by action 2-5(4). Thereafter, the call is routed to domain 20A and the 
actions in domain 20A above described with respect to FIG. 2 occur so that 
the data for service 90 can be obtained from SDF 60A-1. 
FIG. 5 shows another mode of the invention in which database 30G returns 
not only the address for the gateway node for the domain to which service 
90 subscribes, but also the address for the SSP which handles service 90. 
Specifically, when database 30G is queried at action 2-4 with the Servno 
of service 90, database returns as action 2-5 to gateway node 26G a CdPN 
parameter that now includes the address of gateway node 26A 
(GW26A.sub.ADDR), the address of SSP 40A-1 (SSP40A-1.sub.ADDR), and the 
Servno of the called non-geographical service 90, i.e., 
CdPN{GW26A.sub.ADDR, SSP40A-1.sub.ADDR, Servno}. When the IAM is sent at 
action 2-6 to gateway node 26A, gateway node 26A knows the address of the 
SSP (i.e., SSP 40A-1) which handles the service being called, so that 
action 2-9 follows. Actions 2-7 and 2-8 shown in FIG. 2 are obviated by 
the CdPN parameter including the address of the SSP which handles the 
service being called. Actions 2-9 and following in the mode of FIG. 5 are 
identical to those described with reference to FIG. 2. 
FIG. 6 shows yet another mode of the invention in which database 30G 
returns not only the information returned in the mode of FIG. 5, but 
additionally the address for the SCF which handles service 90. The CdPN 
parameter returned by action 2-5 of FIG. 6 includes the address of gateway 
node 26A (GW26A.sub.ADDR), the address of SSP 40A-1 (SSP40A-1.sub.ADDR), 
the address of SCF SOA-1 (SCF50A-1.sub.ADDR), and Servno, i.e., 
CdPN{GW26A.sub.ADDR, SSP40A-1.sub.ADDR, SSP40A-1.sub.ADDR, Servno}. Such 
being the case, SSP 40A-1 obtains the Global Title for SCF 50A-1 from the 
CdPN parameter, so that (in addition to actions 2-7 and 2-8) actions 2-10 
and 2-11 are not performed in the mode of FIG. 6. 
FIG. 7 shows still another mode of the invention in which database 30G 
returns not only the information returned in the mode of FIG. 6, but 
additionally the address for the SDF which handles service 90. The CdPN 
parameter returned by action 2-5 of FIG. 7 includes the address of gateway 
node 26A (GW26A.sub.ADDR), the address of SSP 40A-1 (SSP40A-1.sub.ADDR), 
the address of SCF 50A-1 (SCF50A-1.sub.ADDR), the address of SDF 60A-1 
(SDF60A-1.sub.ADDR), and Servno, i.e., CdPN{GW26A.sub.ADDR, 
SSP40A-1.sub.ADDR, SSP40A-1.sub.ADDR, SDF60A-1.sub.ADDR, Servno}. Such 
being the case, SCF 50A-1 obtains the Global Title for SDF 60A-1 from the 
CdPN parameter, so that (in addition to the actions obviated in the mode 
of FIG. 6) actions 2-13 and 2-14 are not performed in the mode of FIG. 7. 
It should be understood that the modes above discussed with respect to FIG. 
5, FIG. 6, and FIG. 7 are applicable to the each of network 10' of FIG. 3 
and network 10" of FIG. 4, as well as to network 10 of FIG. 1. That is, in 
each of the modes of FIG. 5, FIG. 6, and FIG. 7, database 30G can be 
queried either by gateway node 26G, transit exchange 23G, or local 
exchange 22G. 
FIG. 8 illustrates routing of a call to service 90 after the subscriber 
which offers service 90 has changed telephone service operators, e.g., the 
service is ported from domain 20A to domain 20C. In particular, as shown 
in FIG. 8, data for service 90 is now stored at SDF 60C-1. However, 
service 90 still has the same directory number Servno as formerly when in 
domain 20A. 
Upon the change of subscription depicted by FIG. 8, deletion of the service 
90 from domain 20A was communicated to all databases 30 for database 
updating. In one mode of database updating, the deletion of the service 
from domain 20A was communicated to operator management system (SMS) 32A, 
which advised master service management system (SMS) 32M. SMS 32M 
subsequently communicated the deletion of the service to all SMSs 32, 
including SMSs 32B, 32C, and 32G, which in turn updated respective 
databases 30B, 30C, and 30F, accordingly. Then, when the service joined 
the domain 20C, SMS 32C advised master SMS 32M of the enlistment. SMS 32M 
subsequently advised all SMS 32 of the enlistment in domain 20C of service 
90, including SMSs 32A, 32B, and 32G, which in turn updated respective 
databases 30A, 30B, and 32G, accordingly. In another mode, SMS 32M may 
initially be apprised of deletion of the IN service from domain 20A and 
porting of the IN service to domain 20C, and thereupon advise all other 
operator management systems (SMS) 32 so that the databases 30 can be 
updated. 
Actions 2-1 through 2-4 of FIG. 8 are the same as for FIG. 2, including the 
dialing in action 2-1 of the same directory number Servno as formerly when 
in domain 20A. However, in view of the porting of service 90 to domain 
20C, in action 2-5 the CdPN parameter returned by database 30G includes 
the address of gateway node 26C (GW26C.sub.ADDR) of service 90's new 
domain 20C rather than the address of gateway node 26A of old domain 20A, 
i.e., CdPN{GW26C.sub.ADDR, Servno}. 
The subsequent actions 2-6(8) through 2-6(16) of FIG. 8 are understood with 
respect to correspondingly numbered actions 2-6 through 2-6 of FIG. 2. 
Ultimately the call is routed through gateway 26C, SSP 40C-1, SCF 50C-n, 
and SDF 60C-1 to obtain data for service 90 for completing the call. 
It is understood, of course, that the modes of FIG. 5, FIG. 6, or FIG. 7 
can be implemented for completing the call to service 90 relocated to 
domain 20C in the manner above-discussed with reference to FIG. 8. 
The foregoing exemplary embodiments of the invention particularly show 
routing e.g., to a service control function (SCF) of the telephone service 
operator network of the recipient IN service from a service switching 
function (SSF) of the same telephone service operator network. The 
following embodiments, by contrast, show e.g., examples of routing to a 
service control function (SCF) of the telephone service operator network 
of the recipient IN service from a service switching function outside of 
the telephone service operator network of the recipient service (e.g., 
from the caller's telephone service operator network). 
FIG. 9 shows three telephone service operator networks or domains 
920A-920C. Each domain has a gateway node 926 which is connected to a 
service switching point (SSP) 940. The SSP 940 of each domain 920 is 
connected to a service control function (SCF) 950, which in turn is 
connected to a service data function (SDF) 960. Gateway nodes of the 
various domains are connected together, e.g., gateway node 926B is 
connected to both gateway nodes 926A and 926C. 
Domain 920B further shows that a local exchange 922B is connected to SSP 
940B, and that a subscriber or caller 924B is connected to local exchange 
922B. Domain 920B further includes a database or NAPs 930B, which is 
illustrated as being connected to SSP 940B and to local exchange 922B. In 
addition, SSP 940B of domain 920B is shown as having a signaling 
connection to SCF 950A of domain 920A and to SCF 950C of domain 920C. 
The domains 920A-920C of FIG. 9 are shown in simplified form. It should be 
appreciated that as illustrated the domains include only elements 
necessary for illustrating the present invention, but that in reality 
these domains include further elements such as, for examples, local 
exchanges, further SSPs 940, further SCFs 950, further SDFs 960. 
Similarly, it should be understood that domains 920A and 920C may have 
their own NAPs 930, in which case all NAPs 930 would be connected to an 
unillustrated master or supervisory NAPs. Likewise, domains 920A and 920C 
may have their SSPs connected to SCFs of other domains in the manner 
depicted for SSP 940B of domain 940B. Moreover, it should be understood 
that the SDFs 960 in FIG. 9 may be collocated with SCFs 950 or 
alternatively may be remotely located at SDPS. 
FIG. 9 also shows actions performed when caller 924B dials the directory 
number (Servno) of an intelligent network-type (IN) service which resides 
in domain 920A (i.e., an IN service which is performed by SCF 950A and for 
which data is stored at SDF 960A). Action 9-1 shows the service numbers 
being dialed and forwarded to local exchange 922B. Action 9-2 shows local 
exchange 922B using the Servno to make an inquiry of database 930B 
regarding routing to the dialed IN service. 
At action 9-3, database 930B returns a routing number, e.g., an address as 
to which SSP and which SCF to invoke, for inclusion in a routing message 
such as e.g., a called party number parameter (CdPN). In the illustrated 
example, database 930B returns at action 9-3 the address of SSP 940B and 
the address of SCF 950A, since SCF 950A performs the IN service dialed by 
caller 924B. Action 9-4 shows the routing message, e.g, CdPN, being 
forwarded to SSP 940B. 
SSP 940B uses the address of SCF 950A obtained from the routing message as 
Global Title (GT) when routing in the CCITT Signal No. 7 network to SCF 
950A, as shown by action 9-5. With the call properly routed, SCF 950A, 
using data obtained from SDF 960A, performs the IN service requested by 
caller 924B. 
FIG. 9A shows routing in the event that the IN service dialed by caller 
924B were to change telephone service operators, moving from domain 920A 
into domain 920C. Upon completion of the change of telephone service 
operators, the IN service is performed at SCF 950C upon data stored at SDF 
960C. When the change occurs, database 930B (and any other relevant 
databases) is updated to associate with the address of SCF 950C and the 
address of SSP 940B with the directory number for the IN service. 
Actions 9-1 through 9-4 of FIG. 9A are identical to comparably numbered 
actions of FIG. 9, it being understood that the address of SCF 950C and 
the address of SSP 940B are returned by database 930B in action 9-3. In 
action 9-5, SSP 940B uses the address of SCF 950C obtained from the 
routing message as Global Title (GT) when routing in the CCITT Signal No. 
7 network to SCF 950C. 
FIG. 10 differs from the mode of the invention shown in FIG. 9 in that SSP 
940B, not local exchange 922B, queries database 930B in connection with 
routing of the IN service call (it is assumed in FIG. 10 that the IN 
service still subscribes to the operator of domain 920A and that the IN 
service is performed by SCF 950A). In FIG. 10, at action 10-2 local 
exchange 922B forwards the directory number of the IN service to SSP 940B. 
At action 10-3 SSP 940B performs the query of database 930B, in much the 
same manner as did local exchange did local exchange 922B in FIG. 9. 
Action 10-4 shows database 930B returning to SSP 940B the address of the 
SCF 950A whereat the IN service is performed. In like manner as with FIG. 
9, SSP 940B uses the address of SCF 950A obtained from database 930B as 
Global Title (GT) when routing in the CCITT Signal No. 7 network to SCF 
950A, as shown by action 9-5. With the call properly routed, SCF 950A, 
using data obtained from SDF 960A, performs the IN service requested by 
caller 924B. 
From the foregoing description of FIG. 9A it can be understood from analogy 
what happens should, in the FIG. 10 mode, the IN service changes telephone 
service operators (e.g., moves to domain 920C). 
In the foregoing illustrations, database 930B need not necessarily return 
the entire SCF address to the SSP 940B, but could instead return a pointer 
which the SSP could map to a real SCF address. However, provision by 
database 930B of the entire SCF address to the SSP 940B advantageously 
enables an IN service to be ported to another SCF without requiring the 
SSP to be updated with any new address translation information regarding 
the new SCF. By allowing an SSP outside of the domain which provides the 
IN service to interwork/initiate the IN service, the extent of circuitry 
involved in the transit network is reduced. 
FIG. 13 shows a telecommunications system wherein a NAPs server is employed 
as a Global Title translator for SCCP messages. Four domains 1320A-1320D 
are shown in the system of FIG. 13. Each domain 1320 has a signal transfer 
point (STP) 1321 to which is connected both a service control point (SCP) 
1350 and a service data point (SDP) 1360. Each service control point (SCP) 
1350 is connected to the service data point (SDP) 1360 whose data the SCP 
1350 utilizes, as well as to a signal switching point 1340 of the domain. 
The STPs 1321 of domains 1320A and 1320B are shown as being connected to 
resident databases (NAPs) 1330A and 1330B, respectively. 
In FIG. 13 a centralized node 1330M is connected to STPs 1321 of each of 
domains 1320. Centralized node 1330M includes a NAPs database which 
functions as Global Title translator for SCCP messages routed to node 
1330M. In the embodiment of FIG. 13, SCPs and SDPs need not know that an 
IN service has been ported, since centralized node 1330M w i th its NAPs 
sets up the correct routing. 
It should be understood in FIG. 13 that the SDP is used interchangeably 
with SDF and SCP is used interchangeably with SCF. Likewise, as a variant 
of FIG. 13, each domain 1320 can have its own distributed version of the 
NAPs which resides at node 1330M and c an consult its distributed version 
rather than a centralized node for Global Title translation and the like. 
FIG. 14 shows another embodiment of a telecommunications system wherein 
signal control points access a database in which to determine how IN 
services have been ported. Three domains 1420A-1420c are shown in the 
system of FIG. 14. Each domain 1420 has a signal switching point (SSP) 
1440 to which is connected both a service control point (SoP) 1450 and a 
service data point (SDP) 1460. Each service control point (SCP) 1450 is 
connected to the service data point (SDP) 1460 whose data the SCP 1450 
utilizes, as well as to a signal switching point 1440 of the domain. The 
SDPs 1450 are connected to a centralized NAPs database 1430M. 
FIG. 14 additionally shows that an SCP 1450 of one domain is connected to 
both SCPs and SDPs of other domains, and th at an SDP of one domain is 
connected to an SDP of the other domain. For example, SOP 1450C is 
connected to SCP 1450A and SDP 1460A of domain 1420A and to SCP 1450C and 
SDP 1460C of domain 1420C; SDP 1460C is connected to SDP 1460A and SDP 
1460B. 
In the system of FIG. 14, suppose that SCP 1450C had previously handled a 
particular non-geographical number (e.g., IN service), but that such 
number (e.g., IN service) has now been ported to domain 1420A and is 
handled by SCP 1450A based on data now stored at SDP 1460A. Since the 
non-geographical directory number remains the same despite the porting of 
the IN service, in the particular embodiment of FIG. 14 the call to the IN 
service is routed to the old telephone service operator, and particularly 
to SCP 1450C as shown by action 14-K. Upon receiving a call for an IN 
service which it does not have, SCP 1450C queries NAPs database 1430M as 
indicated by action 14-(K+1) to determine what telephone service operator 
(e.g., which domain) now handles the IN service which has been ported from 
domain 1420C. Action 14-(K+2) shows the address of the SCP which currently 
handles the ported IN service--particularly the address of SCP 
1450A--being routed to SCP 1450C. SCP 1450B then uses the address of SCP 
1450A to route the call to SCP 1450A as indicated by action 14-(K+3). SCP 
1450A then handles the call using data obtained for the IN service from 
SDP 1460A. 
It should be understood also in FIG. 14 that the SDP is used 
interchangeably with SDF and SCP is used interchangeably with SCF. 
Likewise, as a variant of FIG. 14, each domain 1420 can have its own 
distributed version of the NAPs which resides at node 1430M and can 
consult its distributed version rather than a centralized database such as 
database 1430M. 
It should also be understood that an intelligent network (IN)-type service 
has been described in the embodiments herein as merely examples of one 
type of non-geographical number which can be ported according to 
principles of the invention, and that the invention is not to be construed 
as to be limited only to IN services. Rather, the invention has broad 
applicability to portable non-geographical numbers generally. 
In the foregoing examples, for sake of illustration database 30G has 
returned the addresses of various nodes of the domain handling the called 
service as part of the called party parameter CdPN, particularly in the 
Address Signal Field (ASF) thereof. It should be understood, however, that 
an important aspect of the present invention is that database 30G return 
such addresses in a manner usable by a gateway node of the 
service-handling domain. Accordingly, insertion of these addresses is not 
confined to the Address Signal Field (ASF) of the CdPN parameter, or even 
to the CdPN parameter. Rather, these addresses can be applied to a gateway 
node in other forms, such as in other parameters permitted by the 
particular protocol being implemented. 
In the preceding discussion, it should be understood that the term 
"address", used for example with reference to gateway node address, can 
also be a node identifier. 
Whereas the databases 30 have been illustrated as being separate and 
distinct from network nodes in other embodiments databases 30 are included 
as components of the network nodes and accordingly do not involve any 
external signaling. 
While the invention has been particularly shown and described with 
reference to the preferred embodiments thereof, it will be understood by 
those skilled in the art that various alterations in form and detail may 
be made therein without departing from the spirit and scope of the 
invention. For example, it should be understood that the number (four) of 
domains shown in FIG. 1 is for illustrative purposes only, and that a 
greater or lesser number of domains may be employed.