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Claims  |
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What is claimed:
1. A telephone system comprising:
one or more service nodes each including means for establishing one or more
first channels carrying one or more of voice and data information and at
least one second channel for carrying one or more of telephone network
access control and signalling information;
a central office switch for providing for each service node call processing
for calls over said one or more first channels of that service node in
response to signalling on said at least one second channel of that service
node;
one or more service control points each for communicating with said central
office switch for providing information to and receiving information from
said central office switch;
said central office switch being further adapted to have an advanced
intelligence network ("AIN") non-call associated signalling service which
permits a given service node to access a given service control point
through said central office switch and utilizing the at least one second
channel of that given service node.
2. A telephone system in accordance with claim 1 wherein:
said AIN non-call associated signalling service of said switch further
permits a given service control point to access through said switch a
given service node utilizing the at least one second channel of that given
service node.
3. A telephone system in accordance with claim 1 wherein:
a first service control point includes means for correlating subscriber
names and directory numbers;
and a given service node accesses said first service control point to
request said first service control point to correlate the directory number
of a calling party to a subscriber name.
4. A telephone system in accordance with claim 1 wherein:
at least one of said service nodes is a smart private branch exchange
("PBX").
5. A telephone system in accordance with claim 1 wherein:
at least one of said service nodes is a smart phone.
6. A telephone system in accordance with claim 1 wherein:
said one or more first channels and said at least one second channel are
integrated services digital network ("ISDN") channels;
and the one or more of the telephone network access control and signalling
information carried by said at least one second channel comprises ISDN
non-called associated signalling which is processed by said central office
switch utilizing ISDN Common Element Procedures.
7. A telephone system in accordance with claim 1 wherein:
each service node includes means for generating non-call associated
signalling messages each containing an identifier which said central
office switch recognizes as invoking said AIN non-call associated
signalling service of said central office switch, said non-call associated
signalling messages of a given service node being supplied to the at least
one second channel of that service node;
and each service control point includes means for generating non-call
associated signalling messages each containing an identifier which said
central office switch recognizes as invoking said AIN non-called
associated signalling service.
8. A telephone system in accordance with claim 7 wherein:
the system further comprises for each service node, a first interface means
for interfacing that service node with said central office switch, the
first interface means associated with a given service node supporting the
one or more first channels of that service node and the at least one
second channel of that service node;
the non-call associated signalling messages of each service node are
generated as first interface type messages defined by the first interface
means associated with that service node;
the system further comprises for each service control point, second
interface means for interfacing that service control point with said
central office switch,
and the non-call associated signalling messages of each service control
point are generated as second interface type messages defined by the
second interface means associated with that service control point.
9. A telephone system in accordance with claim 8 wherein:
said central office switch, in response to each first interface type
message of a first interface from a given service node and directed to a
given service control point converts the message to a second interface
type message associated with the given service control point and supplies
the converted second interface type message to the second interface
associated with the given service control point for receipt by the given
service control point;
and said central office switch, in response to each second interface type
message of a second interface from a given service control point and
directed to a given service node converts the second interface type
message into a first interface type message associated with the given
service node and supplies the converted first interface type message to
the first interface associated with the given service node for receipt by
the given service node.
10. A telephone system in accordance with claim 9 wherein:
each said conversion of by said central office switch of a first interface
type message to a said second interface type message retains the
origination address, destination address and message contents contained in
the first interface type message;
each said conversion by said central office switch of a second interface
type message to a first interface type message retains the origination
address, destination address and message contents of the second interface
type message.
11. A telephone system in accordance with claim 10 wherein:
each said first interface is an integrated services digital network
("ISDN") interface and each said first interface type message is an ISDN
message;
each said second interface is a signalling system 7 ("SS7") interface and
each said second interface type message is a transaction capabilities
application part ("TCAP") message.
12. A telephone system in accordance with claim 11 wherein:
said central office switch in converting each said first interface type
message to a second interface type message utilizes Common Element ISDN
Procedures.
13. A telephone system in accordance with claim 11 wherein:
said access permitted by said switch of a given service node to a given
service control point permits messages originating at said given service
node to be conveyed to said given service control point and
acknowledgements of said messages originating at said given service node
to be conveyed from said given service control point to said given service
node.
14. A telephone system in accordance with claim 11 wherein:
said AIN non-call associated signalling service of said switch further
permits a given service control point to access through said switch a
given service node utilizing the at least one second channel of that
service node.
15. A telephone system in accordance with claim 14 wherein:
said access permitted by said switch of a given service node to a given
service control point permits messages originating at said given service
node to be conveyed to said given service control point and
acknowledgements of said messages originating at said given service node
to be conveyed from said given service control point to said given service
node;
and said access permitted by said switch of a given service control point
to a given service node permits messages originating at said given service
control point to be conveyed to said given service node and
acknowledgements of said messages originating at said given service
control point to be conveyed from said given service node to said given
service control point.
16. A method for use in telephone system operation comprising:
establishing one or more first channels for carrying one or more of voice
and data information and at least one second channel for carrying one or
more of telephone network access control and signalling information for
one or more service nodes,
processing calls via a central office switch over said one or more first
channels of each service node in response to signalling on said at least
one second channel of that service node;
establishing one or more service control points each for communicating with
said central office switch for providing information to and receiving
information from said central office switch;
establishing via said central office switch an advanced intelligent network
("AIN") non-call associated signalling service which permits a given
service node to access a given service control point through said central
office switch utilizing the at least one second channel of that given
service node.
17. A method in accordance with claim 16 wherein:
said AIN non-call associated signalling service further permits a given
service control point to access through said switch a given service node
utilizing the at least one second channel of that given service node.
18. A method in accordance with claim 16 further comprising:
correlating subscriber names and directory numbers at a first service
control point;
and said step of establishing said AIN non-call associated signalling
service includes permitting a given service node to access said first
service control point to request said first service control point to
correlate the directory number of a calling party to a subscriber name.
19. A method in accordance with claim 16 wherein:
said one or more first channels and said at least one second channel are
integrated services digital network ("ISDN") channels;
and the one or more of the telephone network access control and signalling
information carried by said at least one second channel comprises ISDN
non-called associated signalling which is processed by said central office
switch utilizing ISDN Common Element Procedures.
20. A method in accordance with claim 16 wherein:
for each service node, generating non-call associated signalling messages
each containing an identifier which said central office switch recognizes
as invoking said AIN non-call associated signalling service, and supplying
said non-call associated signalling messages of a given service node to
the at least one second channel of that service node;
and for each service control point, generating non-call associated
signalling messages each containing an identifier which said central
office switch recognizes as invoking said AIN non-called associated
signalling service.
21. A method in accordance with claim 20 wherein:
said method further comprises for each service node, first interfacing the
one or more first channels of that service node and the at least one
second channel of that service node with said central office switch;
the non-call associated signalling messages of each service node are
generated as first interface type messages defined by said first
interfacing associated with that service node;
the method further comprises for each service control point, second
interfacing that service control point with said central office switch;
and the non-call associated signalling messages of each service control
point are generated as second interface type messages defined by the
second interfacing associated with that service control point.
22. A method in accordance with claim 21 wherein:
in response to each first interface type message of said first interfacing
from a given service node and directed to a given service control point
said establishing of said AIN non-call associated signalling service
includes converting the first interface type message to a second interface
type message associated with the given service control point and supplying
the converted second interface type message via the second interfacing
associated with the given service control point to the given service
control point;
and in response to each second interface type message of said second
interfacing from a given service control point and directed to a given
service node said establishing of said AIN non-call associated signalling
service includes converting the second interface type message into a first
interface type message associated with the given service node and
supplying the converted first interface type message via the first
interfacing associated with the given service node to the given service
node.
23. A method in accordance with claim 22 wherein:
each said conversion of a first interface type message to a second
interface type message retains the origination address, destination
address and message contents contained in the first interface type
message;
and each said conversion of a second interface type message to a first
interface type message retains the origination address, destination
address and message contents of the second interface type message.
24. A method in accordance with claim 23 wherein:
said first interfacing is integrated services digital network ("ISDN")
interfacing and each said first interface type message is an ISDN message;
said second interfacing is a signal system 7 ("SS7") interfacing and each
said second interface type message is a transaction capabilities
application part ("TCAP") message.
25. A method in accordance with claim 24 wherein:
said converting of each said first interface type message to a second
interface type message utilizes Common Element ISDN Procedures.
26. A method in accordance with claim 24 wherein:
said access permitted of a given service node to a given service control
point permits messages originating at said given service node to be
conveyed to said given service control point and acknowledgements of said
messages originating at said given service node to be conveyed from said
given service control point to said given service node.
27. A method in accordance with claim 24 wherein:
said AIN non-call associated signalling service of said switch further
permits a given service control point to access through said switch a
given service node utilizing the at least one second channel of that
service node.
28. A method in accordance with claim 27 wherein:
said access permitted of a given service node to a given service control
point permits messages originating at said given service node to be
conveyed to said given service control point and acknowledgements of said
messages originating at said given service node to be conveyed from said
given service control point to said given service node;
and said access permitted of a given service control point to a given
service node permits messages originating at said given service control
point to be conveyed to said given service node and acknowledgements of
said messages originating at said given service control point to be
conveyed from said given service node to said given service control point.
29. A central office switch for use with:
one or more service nodes each including means for establishing one or more
first channels for carrying one or more of voice and data information and
at least one second channel for carrying one or more of telephone network
access control and signalling information; one or more service control
points each for communicating with said central office switch for
providing information to and receiving information from said central
office switch; said central office switch comprising:
means for providing for each service node call processing for calls over
said one or more first channels of that service node in response to
signalling on said at least second channel of that service node; and
said central office switch being further adapted to have an advanced
intelligent network ("AIN") non-call associated signalling service which
permits a given service node to access a given service control point
through said switch and utilizing the at least one second channel of that
given service node.
30. A central office switch in accordance with claim 29 wherein:
said AIN non-call associated signalling service of said switch further
permits a given service control point to access through said switch a
given service node utilizing the at least one second channel of that given
service node.
31. A central office switch in accordance with claim 29 wherein:
said one or more first channels and said at least one second channel are
integrated services digital network ("ISDN") channels;
and the one or more of the telephone network access control and signalling
information carried by said at least one second channel comprises ISDN
non-called associated signalling which is processed by said central office
switch utilizing ISDN Common Element Procedures.
32. A central office switch in accordance with claim 29 wherein: each
service node includes means for generating non-call associated signalling
messages each containing an identifier which said central office switch
recognizes as invoking said AIN non-call associated signalling service of
said central office switch, said non-call associated signalling messages
of a given service node being supplied to the at least one second channel
of that service node; each service control point includes means for
generating non-call associated signalling messages each containing an
identifier which said central office switch recognizes as invoking said
AIN non-called associated signalling service; the central office switch is
for further use with for each service node, a first interface means for
interfacing that service node with said central office switch, the first
interface means associated with a given service node supporting the one or
more first channels of that service node and the at least one second
channel of that service node; the non-call associated signalling messages
of each service node are generated as first interface type messages
defined by the first interface means associated with that service node;
the central office switch is for further use with for each service control
point, second interface means for interfacing that service control point
with said central office switch; and the non-call associated signalling
messages of each service control point are generated as second interface
type messages defined by the second interface means associated with that
service control point; and wherein
said central office switch, in response to each first interface type
message of a first interface from a given service node and directed to a
given service control point converts the message to a second interface
type message associated with the given service control point and supplies
the converted second interface type message to the second interface
associated with the given service control point for receipt by the given
service control point;
and said central office switch, in response to each second interface type
message of a second interface from a given service control point and
directed to a given service node converts the second interface type
message into a first interface type message associated with the given
service node and supplies the converted first interface type message to
the first interface associated with the given service node for receipt by
the given service node.
33. A central office switch in accordance with claim 32 wherein:
each said conversion by said central office switch of a first interface
type message to a said second interface type message retains the
origination address, destination address and message contents contained in
the first interface type message;
each said conversion by said central office switch of a second interface
type message to a first interface type message retains the origination
address, destination address and message contents of the second interface
type message.
34. A central office switch in accordance with claim 33 wherein:
each said first interface is an integrated services digital network
("ISDN") interface and each said first interface type message is an ISDN
message;
each said second interface is a signalling system 7, ("SS7") interface and
each said second interface type message is a transaction capabilities
application part ("TCAP) message.
35. A central office switch in accordance with claim 34 wherein:
said central office switch in converting each said first interface type
message to a second interface type message utilizes Common Element ISDN
Procedures.
36. A central office switch in accordance with claim 34 wherein:
said access permitted by said switch of a given service node to a given
service control point permits messages originating at said given service
node to be conveyed to said given service control point and
acknowledgements of said messages originating at said given service node
to be conveyed from said given service control point to said given service
node.
37. A central office switch in accordance with claim 34 wherein:
said AIN non-call associated signalling service of said switch further
permits a given service control point to access through said switch a
given service node utilizing the at least one second channel of that
service node.
38. A central office switch in accordance with claim 37 wherein:
said access permitted by said switch of a given service node to a given
service control point permits messages originating at said given service
node to be conveyed to said given service control point and
acknowledgements of said messages originating at said given service node
to be conveyed from said given service control point to said given service
node;
and said access permitted by said switch of a given service control point
to a given service node permits messages originating at said given service
control point to be conveyed to said given service node and
acknowledgements of said messages originating at said given service
control point to be conveyed from said given node to said given service
control point.
39. A service node for use with: a central office switch for providing for
said service node call processing for calls over one or more first
channels for carrying one or more of voice and data information of that
service node in response to signalling on at least one second channel for
carrying one or more of telephone network access control and signalling
information of that service node; one or more service control points each
for communicating with said central office switch for providing
information to and receiving information from said central office switch;
said central office switch being further adapted to have an advanced
intelligent network ("AIN") non-call associated signalling service which
permits said service node to access a given service control point through
said switch and utilizing the at least one second channel of said service
node; said service node comprising:
means for establishing one or more first channels for carrying one or more
of voice and data information and at least one second channel for carrying
one or more of telephone network access control and signalling
information; and
means for generating non-call associated signalling messages each
containing an identifier which said central office switch recognizes as
invoking said AIN non-call associated signalling service of said central
office switch, said non-call associated signalling messages of a given
service node being supplied to the at least one second channel of that
service node.
40. A service node in accordance with claim 39 wherein:
said one or more first channels and said at least one second channel are
integrated services digital network ("ISDN") channels;
and the one or more of the telephone network access control and signalling
information carried by said at least one second channel comprises ISDN
non-called associated signalling which is processed by said central office
switch utilizing ISDN Common Element Procedures.
41. A service control point for use with: one or more service nodes each
including means for establishing one or more first channels for carrying
one or more of voice and data information and at least one second channel
for carrying one or more of telephone network access control and
signalling information; a central office switch for providing for each
service node call processing for calls over said one or more first
channels of that service node in response to signalling on said at least
one second channel of that service node; said central office switch being
further adapted to have an advanced intelligent network ("AIN") non-call
associated signalling service which permits a given service node to access
a given service control point through said switch and utilizing the at
least one second channel of that given service node; said service control
point comprising:
means for communicating with said central office switch for providing
information to and receiving information from said central office switch;
and
means for generating non-call associated signalling messages each
containing an identifier which said central office switch recognizes as
invoking said AIN non-called associated signalling service.
42. A service control point in accordance with claim 41 wherein:
said one or more first channels and said at least one second channel are
integrated services digital network ("ISDN") channels;
and the one or more of the telephone network access control and signalling
information carried by said at least one second channel comprises ISDN
non-called associated signalling which is processed by said central office
switch utilizing ISDN Common Element Procedures.
43. A service control point for use with: one or more service nodes each
including means for establishing one or more first channels for carrying
one or more of voice and data information and at least one second channel
for carrying one or more of telephone network access control and
signalling information; a central office switch for providing for each
service node call processing for calls over said one or more first
channels of that service node in response to signalling on said at least
one second channel of that service node; said central office switch being
further adapted to have an advanced intelligent network ("AIN") non-call
associated signalling service which permits said service control point to
access a given service node through said switch and utilizing the at least
one second channel of that given service node; said service control point
comprising:
means for communicating with said central office switch for providing
information to and receiving information from said central office switch;
and
means for generating non-call associated signalling messages each
containing an identifier which said central office switch recognizes as
invoking said AIN non-called associated signalling service.
44. A service control point in accordance with claim 43 wherein:
said one or more first channels and said at least one second channel are
integrated services digital network ("ISDN") channels;
and the one or more of the telephone network access control and signalling
information carried by said at least one second channel comprises ISDN
non-called associated signalling which is processed by said central office
switch utilizing ISDN Common Element Procedures. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
This invention relates to telephone systems and, in particular, to
telephone systems which include central office switches adapted to provide
advanced intelligent network (AIN) operations and services.
One method of providing services in an advanced intelligent network is to
utilize service nodes or intelligent peripherals, e.g., telephone
stations, private branch exchanges, voice mail systems, etc., which have
various degrees of intelligence and which communicate with the central
office switch using message based digital signalling protocols. In many of
these telephone systems, the interface between a service node and the
central office switch is an "integrated services digital network" (ISDN)
interface. ISDN interfaces have two basic common configurations.
In a first configuration, the ISDN interface includes two channels commonly
referred to as the "B" channels (usually 64 Kb/sec) which carry voice
and/or user data information. This first configuration of ISDN interface
also includes a third channel commonly referred as the "D" channel (16
Kb/sec) which carries telephone network access and/or control signalling
information. ISDN interfaces of this first configuration are referred to
as "basic rate" or 2B+D ISDN interfaces.
A second configuration of the ISDN interface is similar to the first
configuration, but the interface includes 23 "B" channels for voice and
data (usually at 64 Kb/sec), in addition to the one "D" channel for access
and/or control signalling (in this case, also at 64 Kb/sec). This second
configuration of the ISDN interface is referred to as a "primary rate" or
23B+D ISDN interface.
Both configurations of ISDN interface and their associated procedures
support the invocation of supplementary services (i.e., requests above and
beyond call establishment) through a protocol called the "Common Element"
procedures. This allows requests to be associated with a current call
(e.g., call transfer), as well as requests that are not directly
associated with a current call. This particular latter subset of the
Common Element procedures is called non-call associated signalling. A
particular example might be non-call associated signalling which is used
to indicate to a subscriber that a message is waiting (i.e., signalling
used to turn on a message waiting indicator on a telephone station at a
subscriber location).
Non-called associated signalling is conveyed in a Facility Information
Element of the ISDN protocol. This information element is usually carried
in a non-call associated message (e.g., the ISDN REGISTER message) which
is identifiable to the central office switch. This message is first
processed in the switch as defined by the ISDN Common Element procedures
and then further processed in the switch as indicated and required by the
specific service (e.g., a message waiting indication service).
A more thorough description of the specifications for ISDN interfaces used
by the regional Bell telephone companies appears in documents known as
Technical References published by Bellcore. These Technical References are
based in part on relevant international standards established for ISDN
signalling (namely Recommendations Q.931 and Q.932) and the relevant
national standards. The Bellcore documents are identified by so called "TR
numbers" and for ISDN interfaces and their associated central office
requirements, the following Technical References have been developed:
TR-NWT-01268, ISDN Primary Rate Interface Call Control Switching and
Signalling Requirements for Class II Equipment; TR-TSY-00268, ISDN Access
Call Control Switching and Signalling Requirements, Issue 3; and
TR-NWT-000864, Common Element Procedures for Service Control, Issue 1. An
example of a specific service that utilizes the existing Common Element
procedures can be found in TR-NWT-000866, ISDN Message Service. The
aforesaid TRs and the aforesaid international and national standards are
known in the telephone system art and their teachings are incorporated
herein by reference.
In telephone systems utilizing conventional and ISDN interfaces, the
central office switches have also been further adapted to include advanced
intelligence network (AIN) capabilities so that the switches can provide
additional services to the telephone subscribers of the system. Central
office switches adapted in this manner are generally referred to as
"service switching points". The additional services that can be provided
by such service switching points include display based delivery of the
calling party's name, audio delivery of the calling party's name,
automatic rerouting of calls based on network failure, etc.
In conjunction with providing these additional services, a central office
switch or service switching point must, in many cases, communicate with an
intelligent computer or so-called "service control point" to obtain
information necessary to complete the service. Thus, for example, when the
central office switch encounters a call to a called subscriber who
subscribes to a service for display based delivery of a calling party's
name (sometimes referred to as "Calling Name Delivery"), the central
office switch will suspend its normal call set-up processing to query a
service control point having a data base which correlates directory
numbers with subscriber names. The query by the central office switch will
request the service control point to search its data base for the
subscriber name having the calling directory number.
Once this calling subscriber information is obtained from the service
control point, the central office switch will complete the call set-up
procedure. When the call is established, the central office switch will
then provide the calling subscriber name to the called subscriber
utilizing analog transmission technologies and thus complete its Calling
Name Delivery service.
The interface between a central office switch and its service control
points in a telephone system is collectively known as "SS7". The SS7
interface is internal to the telephone system and only accessible through
certain types of telephony related equipment (referred to as "network
elements"). The procedures and protocols of SS7 are subdivided into
functional groupings as identified by protocol layers and each network
element processes certain protocol layers. The signalling between an AIN
switch and a service control point largely involves the Transaction
Capabilities Application Part of SS7 more commonly known as TCAP and to a
lesser extent, the Signalling Connection Control Part, more commonly known
as SCCP.
Routing for the SS7 TCAP messages is usually provided by a signalling
transfer point which communicates with the central office switch and the
various service control points. The routing functions are defined in the
Signalling Connection Control Part of SS7. The central office switch
formulates a signalling connection control part message for carrying each
TCAP message. The signalling connection control part message also includes
origination (calling party) address information and destination (called
party) address information.
When a switch sends a TCAP message, the switch`s origination or calling
party address information in the corresponding signalling connection
control part message contains a so-called "signalling point code" which
uniquely identifies the switch. The destination or calling party address
information also includes a sub-system number which identifies a
particular application process of the switch associated with processing
the TCAP message. If AIN processes are involved, the sub-system number is
usually a generic AIN identifier which corresponds to one of the generic
AIN versions (i.e., AIN Release 0, AIN Release 0.1 or potentially AIN
Preliminary Release 0.2).
The destination or called party address information in the signalling
connection control part message contains either a signalling point code
and sub-system number which identify the service control point and the
required application processing or a "global title" identifier and a
"Translation type" identifier. The latter two identifiers permit the
signalling point code and the sub-system number of the destination service
control point to be derived via a translation table at the signalling
transfer point.
When the signalling transfer point receives a signalling connection control
part message, the signalling transfer point routes the message to the
destination service control point based upon the signalling point code and
sub-system number sent in the message or derived from the translation
table at the signalling transfer point. Upon receipt of the routed
message, the destination service control point recognizes the type of
processing that is to be carried out from the sub-system number in the
called party information.
After completing its specific processing as determined by the TCAP message
contents, the service control point may formulate an acknowledgement TCAP
message. This TCAP message is transmitted in a signalling connection
control part message to the signalling transfer point. The signalling
transfer point routes the message back to the central office switch which
is identified in the message by its signalling point code in the called
party information. Upon receipt of the signalling connection control part
message, the switch retrieves the TCAP message to obtain the information
provided by the service control point to complete the AIN service.
A more extensive description of the specifications for SS7 interfaces,
including the signal connection control part messages and TCAP messages,
is provided in Bellcore TR-NWT-000246, Signalling System Number 7, Issue
2. Also, the AIN Release 0.1 and the Preliminary AIN Release 0.2 are
described in detail in Bellcore Technical Requirements TR-NWT-001285,
TR-NWT 001284 and Technical Advisories TA-NWT-1299, TA-NWT-1298 and
TA-NWT-001129. The aforesaid Bellcore TRs and TAs are also incorporated
herein by reference and likewise are known in the telephone system art.
In the above-described non-call associated signalling schemes defined in
TCAP in SS7 and in the Common Element Procedures of ISDN, each non-call
associated message includes a "component" which indicates the status of
the operation. The following components are used: (a) Invoke; (b) Return
Result; (c) Return Error; and (d) Reject.
The Invoke component in a message indicates that the identified operation
in the message is being requested. The Return Result component indicates
that the associated operation is being positively acknowledged and the
Return Result may contain information necessary in providing the
acknowledgment (i.e. the information requested). The Return Error
component indicates that the associated operation is being negatively
acknowledged, i.e., that the entity that received the message was not able
to carry out the requested operation. The Return Error component may
contain information as to the reasons why the operation could not be
carried out. The Reject component indicates that the entity that received
the message was not able to understand the nature of the requested
operation at all.
As above-indicated, a central office switch communicates with its service
control points based on the aforesaid TCAP SS7 messages, while it
communicates with its service nodes based on the aforesaid ISDN messages.
The central office switch does not permit the service control points to be
accessed by the service nodes (or any other subscriber or customer
premises equipment) or vice-versa, i.e., the service nodes to be accessed
by the service control points, via directory dialing or any other means.
This is a disadvantage since access of the service nodes and the service
control points to each other in a telephone system may be desirable to
permit AIN processes to be directly requested or effected.
It is, therefore, an object of the present invention to provide a telephone
system in which the service nodes and the service control points of the
system can access one another in an efficient and cost effective manner.
It is a further object of the present invention to provide a telephone
system meeting the above objective in which ISDN interfaces with ISDN
messages are used between the service node and the central office switch
and SS7 interfaces with TCAP messages are used between the central office
switch and the service control points.
It is yet a further object of the present invention to provide a telephone
system meeting the above objectives and which utilizes existing procedures
to the greatest extent possible.
It is still a further object of the present invention to provide a service
node, central office switch and service control point for a telephone
system meeting the above objectives.
SUMMARY OF THE INVENTION
In accordance with the principles of the present invention, the above and
other objectives are realized in a telephone system of the above-type in
which a central office switch is adapted to have a non-call associated
signalling class of communication service (referred to herein as "AIN
non-call associated signalling") in which the switch allows a service node
and a service control point to communicate or access each other using
non-call associated signalling supportable by the respective interfaces
connecting the service node and the service control point to the switch.
Communication between the switch and the service node is over the
telephone network access control and/or signalling channel of the
interface connecting the service node to the switch. With the central
office switch adapted in this manner, messages (e.g., requests, data,
etc.) can be transmitted between the service node and the service control
point via the switch using existing facilities and interfaces and without
the need to add further protocols between the switch and service control
point or the between the switch and service node.
In the embodiment of the invention to be disclosed hereinafter, the
interface to the service node is an ISDN interface and non-call associated
signalling is carried between the service node and the switch on the
access control and/or signalling channel of the ISDN interface, i.e., on
the D channel. The switch and the service control point, in turn,
communicate via a SS7 interface and non-call associated signalling as
defined by TCAP.
Accordingly, the central office switch, in effecting its AIN non-call
associated signalling receives the AIN non-call associated signalling on
the ISDN interface from the service node and converts it to AIN non-call
associated signalling in the TCAP protocol on the SS7 interface and sends
it to the service control point. The switch accomplishes this without
having to decipher or process the application level data that is passed
between the service node and service control point (i.e., the
envelop.sub.-- contents parameter discussed hereinafter).
In the other direction, the switch in receiving the AIN non-call associated
signalling on the SS7 interface from the service control point using the
TCAP protocol converts this to the corresponding AIN non-call associated
signalling on the ISDN interface and sends it to the service node. The
switch, again, does this without having to decipher of process the
application level data that is passed from the service control point to
the service node. An efficient and cost effective way of communicating
requests and data between the service node and the service control point
is thereby effected.
In the disclosed embodiment, each AIN non-call associated message includes
a component as above-mentioned (i.e., Invoke Return Result, etc.) which
identifies and conveys information regarding an operation whose presence
signifies to the central office switch that the service being invoked is
AIN non-call associated signalling. The identified operation includes
parameters which indicate the address of the originating entity (called
origination.sub.-- address), the address for the destination entity (call
destination.sub.-- address), and the message contents which is the data to
be sent from the service node to the service control point to effect the
desired AIN service (called the envelope.sub.-- contents).
The coding of the first two elements is based on the coding format of the
existing ISDN Called Party Address and Calling Party Address information
elements. These protocol elements provide a variety of methods to indicate
various addressing methods using the standard coding format. The coding of
the envelop.sub.-- contents is defined and specified between the service
node and the service control point. It should be noted that other
parameters can be added to facilitate the processing of the envelop.sub.--
contents field in the service node and service control point. One such
parameter is the envelope.sub.-- format.sub.-- indicator which can be used
to define the structure and format of the envelop.sub.-- contents.
However, the contents of this parameter is not required to be known or
deciphered by the switch in providing the AIN non-call associated
signalling. The switch uses the origination and destination addresses,
while replicating and without deciphering or processing (i.e., acting on)
the message contents in effecting its conversion processing.
Specifically, the switch processes each AIN non-call associated ISDN
message using ISDN Common Element procedures followed by the conversion
processing which results in an AIN non-call associated TCAP message having
an operation corresponding to the operation in the ISDN message and
parameters (origination address, destination address and message contents)
which are the same as those in such message. Additionally, in the
disclosed embodiment, two ISDN operations and two corresponding TCAP
operations are used. One of the ISDN operations and its corresponding TCAP
operation require an acknowledgement or respon | | |
