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TECHNICAL FIELD
This invention relates to communication systems.
BACKGROUND OF THE INVENTION
For most communications services, prior art communications network
architecture limits a subscriber's ability to freely select services
and/or service providers. For example, most subscribers are constrained to
receive their local communications services exclusively from the carrier
e.g., a local phone company, or a cable television operator, serving the
geographical area where those subscribers live. Thus, those subscribers
are limited to the services provided by their serving local carrier(s)
singly or in agreement with other carriers. For some other communications
services, such as long distance or cellular communications services,
subscribers typically have more freedom in the selection of service
providers. However, the inflexibility of today's communications network
architecture prevents subscribers from freely mixing and matching features
from different carriers for a particular service. Thus, a problem of the
prior art is a rigid communications architecture which does not allow
subscribers to select feature and/or services from competing carriers on a
call-by-call basis or on a subscription basis.
Another problem of the prior art is the inability of end-users who have
access/egress facilities to multiple competing carriers to specify a
particular carrier from which they want to receive incoming communications
services.
SUMMARY OF THE INVENTION
We have realized that the root causes of the aforementioned prior art
problems can be traced back to the logical dependency of end-user
signaling systems on end-user switching points. Specifically, the end-user
switching points originate, process and terminate signaling messages for
end-user devices. Because of that dependency, the end points for user
signaling are switching systems that are generally managed and owned by a
single communications carrier, such as a Local Exchange Carder (LEC), a
cellular communications provider or a cable television operator. Thus, the
communication carrier that controls the local loop associated with the
terminal device of a subscriber also controls the nature and type of
signaling messages for all communications services received and requested
by that subscriber over that loop. Hence, the subscriber is at the mercy
of the loop-controlling communications carrier (transport provider) for
the type of communications services and features available to that
subscriber.
The present invention is directed to a communications network architecture
in which, a subscriber is allowed to select a signaling provider
independently of a) the transport carriers which control the local loops
for particular communications services, and b) the providers of those
services. In accordance with the principles of the invention,
bidirectional signaling messages associated with communications services
requested by, or destined for a subscriber's terminal device are sent
unprocessed to a signaling provider selected by the subscriber. The
signaling provider then requests those services from the service providers
selected by the subscriber.
In a preferred embodiment of the invention, a user establishes a signaling
connection to a node of a signaling provider of his or her choice via a
transport provider network. The signaling provider node processes call
setup signaling messages to determine the type of connections and services
desired by the user. The signaling provider node then retrieves a profile
associated with the terminal device or user-identification information
contained in a signaling message. The profile identifies through a table
lookup operation, the particular features and service providers selected
by the user. Service providers are selected by a user either on a
subscription basis or on a call-by-call basis. In the latter case, service
provider identification information needs to be included in the call setup
signaling message. Once the appropriate service providers have been
identified, the signaling provider node initiates and transmits service
request signals to each of the signaling nodes of those service providers
networks to set up the appropriate connections for the user's call. If the
services requested by the user are limited to information retrieval, the
retrieved information is then delivered to the user by the service
provider over the facilities of the access transport provider that is
determined from the aforementioned table lookup operation.
If interactive conversational services are requested by the subscriber, the
signaling provider of the subscriber communicates with the signaling
provider of each called party to determine the selected transport provider
for incoming communications services for each called party who has
access/egress facilities to more than one transport provider. Once the
egress transport provider is identified for each called party, the
subscriber's signaling provider establishes the appropriate connection(s)
between the subscriber and each called party over the local loop (and
other loops, if needed) of the transport provider of each called party.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram illustrating a narrowband communications system
embodying the principles of the invention;
FIG. 2 shows a block diagram of a broadband communications system arranged
in accordance with the principles of the invention;
FIG. 3 shows a table illustrating subscribers' profiles that are stored in
a signaling provider's network; and
FIG. 4 is a flowchart describing the logical sequence of steps in methods
for completing calls in the communications system of FIG. 1 or FIG. 2.
DETAILED DESCRIPTION
FIG. 1 is a block diagram illustrating a narrowband communications system
embodying the principles of the invention. The narrowband communications
network illustrated in FIG. 1 is arranged to support Narrowband Integrated
Services Digital Network (N-ISDN) standards from a signaling standpoint as
well as from a transport perspective. Shown in FIG. 1 are transport
provider and local service provider networks 100, 110, 180 and 190; long
distance service provider networks 130 and 140; multimedia service
provider networks 150 and 160; and signaling provider networks 120 and
170. Local Transport provider and local service provider networks 100,
110, 180 and 190 may be Local Exchange Carrier (LEC), cable television
operator networks or cellular telephone networks or a combination of the
above. One of the main characteristics of transport provider and local
service provider networks 100, 110, 180 and 190 is that they provide the
local loop to end-user devices at subscribers' premises.
In FIG. 1, user devices, such as telephone set 101, processor 102 and
videophone 103 are connected to multiplexer/demultiplexer 104 via Basic
Rate Interface (BRI) access/egress links 109, 108, 107, respectively. As
is well known in the art, one of the N-ISDN transport standards is the
Basic Rate Interface (BRI) specification which defines operating
parameters for the transmission and reception of multiplexed digital
information (user information and signaling information) over a two-wire
or four-wire digital subscriber loop. Digital information received and
transmitted over that loop is logically partitioned into two bearer (B)
channels for user information, and one data (D) channel for signaling
information. The logical partitioning of dam over those channels is
commonly referred in the art as the "2B+D interface". That interface is
also supported on access/egress links 117-119 that connect end-user
devices 111-113 to multiplexer/demultiplexer 114. BRI access/egress links
are also provided to mux/demux 184 and 194 for end-user devices 181-183
and 191-193, respectively. End-user devices 101 to 103, 111 to 113, 181 to
183 and 191 to 193 are ISDN-compatible devices that are arranged to
packetize signaling information that is transmitted over the D channel to
initiate communications with other ISDN-compatible devices.
Multiplexer/demultiplexers 104-114 and 184-194 demultiplex signaling data
received over the D channel and forward those signals to Signaling Nodes
121 and 171, respectively. User information destined for the end-user
devices are transmitted to those devices via the B channels of the
access/egress links. User information received from the end-user devices
are routed by multiplexer/demultiplexers 104-114 and 184-194 to switches
106-116 and 186-196, respectively. The latter switches are
software-driven, processor-controlled telephone systems designed to route
calls either from one switch to another or to end-user devices. A
well-known Local Service Provider switch is the AT&T No. 5ESS.RTM. which
is described in AT&T Technical Journal, Vol. 64, No. 6, part 2, pp.
1305-1564, July/August, 1985.
Also shown in FIG. 1 is signaling provider network 120 (170) which includes
a signaling service provider node (hereinafter called SSP) 121 (171) and a
toll switch 122 (172). The latter switch, which may be implemented using,
for example, an AT&T No. 4ESS.RTM., is a software-driven,
processor-controlled switching system which is arranged to communicate
primarily with other toll switches or central office switches. SSP node
121 (171) performs three primary functions. First, SSP node 121 (171) is
the access and egress point for all signaling messages received from, and
destined for the end-user devices. Secondly, SSP node 121 (171) processes
the received signaling messages by requesting from the appropriate service
providers the necessary connections, based on the services requested by
the users. Thirdly, it exchanges signaling messages with switches and
processors in the network of FIG. 1 via other signaling nodes. While SSP
node 121 (171) is illustrated in FIG. 1 as one physical node for the sake
of simplicity, it is to be understood that SSP node 121 (171) may be
composed of a plurality of interconnected nodes within signaling provider
network 120, which can be arranged to switch signaling information
according to ISDN-based signaling specific protocol.
FIG. 1 also discloses subscribers' database 123 (173) that is connected to
SSP node 121 (171). Subscriber's database 123 (173) is a computer system
with mass storage that contains addresses of particular service providers
selected by each subscriber. A detailed description of the format in which
information is stored in database 123 (173) is provided below.
Also shown in FIG. 1 are long distance service provider networks 130 (140)
and multimedia service provider 150 (160). Long distance service provider
network 130 (140) is comprised of toll switches 131 (141), 132 (142), and
133 (143) that are interconnected by transmission systems. Long distance
service provider network 130 (140) is arranged to route calls to
destination addresses received by Signaling Service Node 134 (144)
(hereinafter called SSN) from SSP node 121 or 171. Similarly, multimedia
service provider network 150 (160) receives destination addresses via SSN
154 (164). Multimedia service provider network 150 (160) may contain, for
example, a repository of information such as data library, digitized
imaging information, digital voice mail systems. Users wishing to get
access to a particular type of stored information in multimedia service
provider network 150 (160) provides addressing information to the
signaling node of their signaling provider network which requests
connection(s) to the targeted service from multimedia service provider
network 150 (160) via SSN 154 (164).
FIG. 2 shows a block diagram of a broadband communications system arranged
in accordance with the principles of the invention. In FIG. 2, end-user
device 201 (202) is connected to two separate transport providers networks
206 and 203 (250 and 220). End-user device 201 is an integrated television
and workstation which is equipped with a camera and a telephone set and
which is arranged to process digital information in the form of voice
data, image and video. The transport provider networks 206 and 203 (220
and 250) to which end-user device 201 (202) is connected, include
Asynchronous Transport Mode (ATM) switches 2061 and 2031 (2501 and 2101),
respectively. The latter switches are fixed-length cell (packet), digital,
self-routing switching systems comprised of a switching fabric designed to
route cells to logical channels indicated by their headers independently
of the applications or media. ATM switches 2061 and 2031 (2501 and 2101)
also include a) line cards (not shown) that are designed to terminate
incoming ATM lines 2030 (2500) and 2060 (2200) connected to end-user
device 201 (202), and b) trunk cards terminating trunk facilities 2032 and
2072 (2502 and 2072) that provide channel links between ATM switches 2031
(2101) and 2071 (2501). Also included in ATM switches 2031 (2501) and 2061
(2201) are components, such as multiplexing/demultiplexing modules and
cross-connect hardware (not shown). Those components are arranged to
multiplex lower speed input traffic (received from line cards connected to
end-user devices 201 and 202) into the higher speed switching fabric which
supports Virtual Path and Virtual Circuit connections as defined in CCITT
broadband standards. In particular, the CCITT standards provide for a
routing header to be prepended to each cell. The header of each cell is
comprised of fields which store Virtual Channel Indicator (VCI) and
Virtual Path Indicators (VPI) data. The VPI data identify a logical
channel (that may be subdivided into lower bandwidth logical channels
identified by VCI data) for a physical transmission path between two end
points. The CCITT standards further proscribe for a lookup table to map
input pair of VPI/VCI for each cell to a corresponding output pair of
VPI/VCI before a cell is transferred from one channel link (between two
switching points) to another. Thus, a virtual channel connection is
defined as the association of all the individual channel links between
each pair of switches as determined by the lookup tables in those
switches. If, for example, signaling provider network 207 is selected by
the user of device 201 as the "signaling agent" for all services requested
by device 201, then all signaling messages initiated by or destined for
end-user 201 are processed by signaling provider network 207.
In this example, virtual channel connections are used to transport users'
real data (payload) as well as user signaling information to a signaling
provider selected by a user. While protocols for signaling messages are
still being defined by the international standard bodies, it is clear that
the ATM Adaptation Layer (AAL) will be used for signaling messages. Thus,
signaling messages will be carded as cells or frames in all signaling
connections (point-point or multipoint) between an end-user device and ATM
switches or any intelligent node in the network.
Also included in signaling providers networks 207 and 210 are databases
2072 and 2102, respectively. Those databases store signaling provider
profile information which identifies the particular service providers and
features selected by a subscriber. The type of information that is stored
in databases 2072 and 2102 are described in further detail below.
Signaling provider networks 207 and 210 are arranged to a) receive
signaling requests for access to services from end-user devices 201 and
202, and b) establish the appropriate connections to service providers
networks selected by the users as determined by the end-user profiles.
Although signaling provider networks 207 and 210 are shown as separate and
independent networks, it is to be understood that the capabilities of
signaling provider networks 207 and 210 can be included in multimedia
service provider network 209 or 208 or long distance service provider
network 205 or 230.
FIG. 2 also depicts long distance provider networks 205 and 230. The latter
are communications systems comprised of ATM switches interconnected by
transmission facilities to establish multimedia connections requested by
users. For the sake of simplicity the ATM switches in long distance
provider networks 205 and 230 are represented by a single switch 2051 and
2301, respectively. Multimedia connections that can be established over
long distance networks 205 and 230 include audio (low and high fidelity),
video (high and low bandwidth moving pictures) images (high bandwidth
scanned images). These multimedia connections allow broadband multimedia
telephony services to be provided between two locations. Long Distance
Service provider network 205 (230) is also arranged to provide video and
audio teleconferencing services between more than two locations.
Also illustrated in FIG. 2 are multimedia service provider networks 208 and
209. Multimedia service provider network 208 (209) includes a Service
Control Point 2081 (2091) and a database 2082 (2092). Service Control
Point 2081 (2091) is a preprocessor arranged to recognize the particular
multimedia service requested by a user and to formulate a query that is
launched to database 2082 (2092) to retrieve the particular set of
information desired by the user. Hence, Service Control Point 2081 (2091)
acts as an interface between signaling provider networks 207 and 210 and
database 2082 (2092). Service Control Point 2081 (2091) may also provide
the human interface between Database 2082 (2092) and the users. Database
2082 (2092) is a processor-controlled mass storage device that contains
bandwidth-intensive digitized imaging information such as medical images
(X rays and MRI data), movies, video mail messages, to name a few.
FIG. 3 shows a table illustrating subscribers' profiles that are stored in
a signaling provider's network. The table of FIG. 3 contains information
that is grouped under four major headers, namely, subscribers' addresses,
transport/service providers, incoming services and outgoing services. The
subscriber's address field typically identifies the telephone number of a
subscriber. For data retrieval service applications, however, a physical
port identification number may also be used as a subscriber's address.
Under the transport/service providers header are grouped three segments,
namely, access, egress and long distance. Each segment comprises two
fields, namely, voice and multimedia. The voice field in all three
segments indicates the transport/service provider selected by a subscriber
for communications services, such as conventional telephony, voiceband
data, low bandwidth video services (less than 64 kilobits per second), to
name a few. The multimedia field identifies a particular multimedia
service/transport provider selected by a subscriber for communications
services in which two bearer (B) channels are used for mixed voice, data
and video applications. The access and egress segments identify the
transport providers selected by a subscriber for receiving voice or
multimedia communications services. For example, subscriber-1 has selected
a) his/her Local Exchange Carder as the transport provider for
access/egress local telephone services, and b) Monmouth Cable TV Company
as the access/egress transport provider for multimedia services. The long
distance segment identifies the service/transport provider selected by the
subscriber for voice and multimedia long distance services. For example,
subscriber-2 has opted to use US Sprint and Iridium as the long distance
service provider for voice and multimedia services, respectively.
Subscriber-1 has selected AT&T as the long distance service provider for
both voice and multimedia services. The voice field in all three segments
indicates the transport/service provider selected by a subscriber for
communications services, such as conventional telephony, voiceband data,
low bandwidth video services (less than 64 kilobits per second), to name a
few. Multimedia Services refer to communications services in which two
bearer (B) channels are used for mixed voice, data and video applications.
Also shown in FIG. 3 is the incoming services header. Under that header are
grouped particular incoming call features selected by a subscriber. For
the sake of simplicity, only call waiting and voice mail are shown as
incoming call features in FIG. 3. It is to be understood, however, that
other incoming call features, such as call forwarding, call restriction or
call redirection can also be part of a subscriber's profile.
A subscriber can also include in his/her profile desired features for
outgoing calls. Those features are illustrated in FIG. 3 as quality of
service field for voice and video services. For example, subscriber-2 has
opted for high quality for voice and video services. High quality for
audio services in an N-ISDN environment may be implemented by dedicating
an end-to-end full bearer channel--sixty-four (64) kilobits, as opposed to
fifty-six (56) kilobits--for a regular telephone call. In a broadband
environment, high quality audio services may require high fidelity
characteristic for a call. High quality video in a broadband ISDN
environment may require the use of High Definition Television (HDTV)
standards for video connection, as opposed to the lower
bandwidth-intensive National Television Standards Committee (NTSC)
standards for a video call.
FIG. 4 is a flowchart describing the logical sequence of steps in an
illustrative method for completing calls in the N-ISDN communications
system of FIG. 1 and the broadband communications network of FIG. 2. That
method is initiated in step 401, when a user at device 113 (of FIG. 1) or
device 201 (of FIG. 2) for example, places a video call by dialing a
called party number. The dialing of that number causes a signaling message
to be launched to the signaling service provider pre-selected by the user.
For example, in FIG. 1, a Q.931 or (alternatively) an ISUP information
message is launched to the SSP node 121 of signaling service provider 120
via the signaling channel (D channel or SS7 link) of loop 117 and
mux/demux 114. When the ISUP protocol is used, the signaling information
message is carried in an Message Transfer Part (MTP) packet that allows
the mux/demux 114 to route the signaling message directly to the SSP node
121. Similarly, when the Q.931 protocol is used, the signaling information
message is carried in a "Link Access Procedures on the D channel" (LAPD)
packet that allows the mux/demux 114 to route the signaling message to SSP
node 121 using well-known frame relay switching techniques. As to FIG. 2,
the signaling message is a Q.93B message that is included in one or more
ATM cells that are routed to signaling provider 207 by transport provider
network 203 or 206, based on the VPI/VCI of the cell(s).
Upon receiving the signaling message, the signaling provider network, in
step 402, extracts information from the message to identify the calling
party address or number, the requested services and the called party
address or number. For example, in FIG. 1, SSP node 121 extracts the ISUP
(Q.931) information message from the MTP (LAPD) packet and identifies the
calling party, the requested services, and the called party. Similarly, in
FIG. 2 the headers and ATM Adaptation Layer (AAL) related bits are
discarded to identify the requested service(s) and the addresses of
calling and called parties.
The signaling provider node proceeds, in step 403, to query an attached
database to identify any particular features that are associated with the
requested service(s) and that have been pre-selected by the user. In FIG.
1, SSP node 121 queries database 123 to determine whether the user has
subscribed to any of those features. In FIG. 2, ATM switch 2071 queries
database 2072 to inquire about the aforementioned features. This
determination is based on the user's profile that is illustrated in FIG.
3. Thereafter, in step 404, the signaling provider of the called party is
identified. Two alternate methods can be used to identify the signaling
provider of the called party. The address of the signaling provider of the
called party may be stored in database 123 of FIG. 1 or database 2072 of
FIG. 2. Hence, a database search that uses the called party number as a
key allows the signaling provider of the called party to be identified.
Alternatively, information associated with the signaling provider of the
called party may be included in the dialed number that is included in the
signaling message received by signaling provider network 120 or 207. For
example, if AT&T is the signaling provider of subscriber-1 in FIG.. 3, a
caller who wants to direct a call to subscriber-1 will dial the number of
subscriber-1 preceded by X288 where "X" is a digit between 0 and 9 and 288
corresponds to the letters A,T,T on the dialpad.
Once the signaling provider of the called party has been identified, the
signaling provider network of the calling party, in step 405, sends a
signaling message to the signaling provider of the called party indicating
the requested services that are to be provided to the called party. In
FIG. 1, SSP 121, sends an ISUP information message to the called party SSP
node, in this case SSP 171. The message is carried in an MTP packet that
is routed by intervening SSPs (if any) to SSP 171. In FIG. 2, ATM switch
2071 sends a B-ISUP message to the called party signaling provider, in
this example ATM switch 2104 indicating the particular service that is
destined for the called party. It is worth noting that step 405 is skipped
when the calling and called parties have a common signaling provider.
In step 406, the signaling provider network queries its database to
identify any pre-selected features that are associated with the services
destined for the called party. For example, in FIG. 1, SSP node 171
queries database 173 to determine a) the egress transport provider
selected by the called party and, b) the features pre-selected by the
called party for incoming calls. Similarly, in FIG. 2, ATM switch 207 1
queries database 2072 to determine the associated features and the
transport provider pre-selected by the called party.
In step 407, the called party signaling provider network responds to the
the message of the calling party signaling provider network by identifying
the address of the transport provider pre-selected by the called party and
the particular features associated with the service(s) destined for the
called party. Illustratively, in FIG. 1, SSP node 171 sends to SSP node
121 an ISUP information message which contains addressing information of
the called party's transport provider and incoming call feature routing
information, if any. As to FIG. 2, ATM switch 2104 sends a B-ISUP message
to ATM switch 2071 containing addresses of the transport provider
pre-selected by the called party for that service and any features
associated with that service.
Upon receiving the signaling message from the signaling provider of the
called party, the signaling provider of the calling party has all the
information required to invoke the services requested by the caller and to
deliver those services. Hence, in step 408, the signaling provider network
of the calling party, sends a signaling message to the appropriate service
providers of the calling and called parties to establish a connection
between those parties. In FIG. 1, SSP 121, sends an information message to
the access switch (in this example, access switch 116) of the transport
provider to establish a connection between the calling party and the
called party. The access switch 116 seizes the incoming line 117 from the
calling party by generating an IAM message to end-user device 113. Access
switch 116, then sends an IAM signaling message to switch 122 which, in
turn, forwards that message to a switch of the long distance provider, say
switch 133. The latter propagates the IAM message through the long
distance service provider network to switch 172 and ultimately to egress
switch 186. Alternatively, a direct connection via a link can be
established between switches 116 and 133 and/or between switches 186 133
after exchanging signaling messages between those switches. After ISUP
answer messages have been returned to access switch 116, the call is
completed in a conventional manner.
The connection is established in FIG. 2 by ATM switch 2071 sending a) call
request signaling messages to the pre-selected service providers
associated with the services requested by the user, and b) connection
request signaling messages to the transport provider pre-selected by the
called party. For example, ATM switch 2071 can issue a) a call request to
SCP 2081 of multimedia service provider 208, and b) a connection request
to transport provider 220 to establish a video connection to user 202.
If additional signaling messages are needed to add, for example, a third
party to the call, in step 409, those messages are sent directly to SSP
node 121 or 171, of FIG. 1 or ATM switch 2071 or 2104 of FIG. 2, as
described above.
The foregoing merely illustrates the invention. Those skilled in the art
will be able to devise numerous arrangements which, although not
explicitly shown or described herein, embody the principles of the
invention and are within their spirit and scope.
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