U.S. patent application number 11/075151 was filed with the patent office on 2005-08-11 for system and method for connecting a call.
This patent application is currently assigned to SPRINT COMMUNICATIONS COMPANY L.P.. Invention is credited to DuRee, Albert Daniel, Gardner, Michael Joseph, Howell, Royal Dean, Nelson, Tracy Lee, Wiley, William Lyle.
Application Number | 20050174999 11/075151 |
Document ID | / |
Family ID | 25317994 |
Filed Date | 2005-08-11 |
United States Patent
Application |
20050174999 |
Kind Code |
A1 |
Wiley, William Lyle ; et
al. |
August 11, 2005 |
System and method for connecting a call
Abstract
Signaling processors process signaling to transfer first and
second control messages indicating interworking information.
Interworking units receive the control messages and user
communications, and in response, convert the user communications
into packet communications having the interworking information in
headers. Communication devices receive the packet communications
from the interworking units and route the packet communications
over optical communication paths based on the interworking
information in the headers. The communication devices receive the
routed packet communications and transfer the routed packet
communications to the interworking units. The interworking units
receive the second control messages and the routed packet
communications, and in response, to convert the routed packet
communications into the user communications and transfer the user
communications.
Inventors: |
Wiley, William Lyle;
(Olathe, KS) ; Gardner, Michael Joseph; (Overland
Park, KS) ; Nelson, Tracy Lee; (Shawnee Mission,
KS) ; Howell, Royal Dean; (Trimble, MO) ;
DuRee, Albert Daniel; (Independence, MO) |
Correspondence
Address: |
SPRINT
6391 SPRINT PARKWAY
KSOPHT0101-Z2100
OVERLAND PARK
KS
66251-2100
US
|
Assignee: |
SPRINT COMMUNICATIONS COMPANY
L.P.
|
Family ID: |
25317994 |
Appl. No.: |
11/075151 |
Filed: |
March 8, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11075151 |
Mar 8, 2005 |
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09642722 |
Aug 21, 2000 |
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6885671 |
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09642722 |
Aug 21, 2000 |
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08854194 |
May 9, 1997 |
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6137800 |
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Current U.S.
Class: |
370/386 |
Current CPC
Class: |
H04Q 3/0029 20130101;
H04Q 3/0025 20130101; Y10S 370/907 20130101 |
Class at
Publication: |
370/386 |
International
Class: |
H04Q 011/00; H04L
012/50 |
Claims
What is claimed is:
1. A communication system comprising: a plurality of signaling
processors; a plurality of interworking units linked to the
signaling processors; a plurality of optical communication paths; a
plurality of communication devices coupled to the interworking
units wherein each pair of the communication devices are coupled
together by one of the optical communication paths to form a flat
architecture between the communication devices; wherein the
signaling processors are configured to receive and process
signaling, and in response, to generate and transfer first control
messages and second control messages indicating interworking
information; wherein the interworking units are configured to
receive the first control messages and user communications, and in
response, to convert the user communications into packet
communications having the interworking information in headers of
the packet communications and transfer the packet communications to
the communication devices; wherein the communication devices are
configured to receive the packet communications from the
interworking units, route the packet communications over the
optical communication paths based on the interworking information
in the headers, receive the routed packet communications from the
optical communication paths, and transfer the routed packet
communications to the interworking units; and wherein the
interworking units are configured to receive the second control
messages and the routed packet communications, and in response, to
convert the routed packet communications into the user
communications and transfer the user communications.
2. The communication system of claim 1 wherein the packet
communications comprise asynchronous transfer mode
communications.
3. The communication system of claim 1 wherein the communications
devices comprise asynchronous transfer mode devices.
4. The communication system of claim 1 wherein the user
communications comprise time division multiplex communications.
5. The communication system of claim 1 wherein the user
communications comprise analog voice communications.
6. The communication system of claim 1 wherein the signaling
comprises broadband signaling.
7. The communication system of claim 1 wherein the signaling
comprises Signaling System Seven (SS7) signaling.
8. The communication system of claim 1 wherein the signaling
comprises initial address messages.
9. The communication system of claim 1 wherein the signaling
comprises Integrated Service Digital Network (ISDN) signaling.
10. The communication system of claim 1 wherein the optical
communication paths comprise Synchronous Optical Network (SONET)
paths.
11. A method of operating a communication system comprising a
plurality of signaling processors, a plurality of interworking
units linked to the signaling processors, a plurality of optical
communication paths, and a plurality of communication devices
coupled to the interworking units wherein each pair of the
communication devices are coupled together by one of the optical
communication paths to form a flat architecture between the
communication devices, the method comprising: in the signaling
processors, receiving and processing signaling, and in response,
generating and transferring first control messages and second
control messages indicating interworking information; in the
interworking units, receiving the first control messages and user
communications, and in response, converting the user communications
into packet communications having the interworking information in
headers of the packet communications and transferring the packet
communications to the communication devices; in the communication
devices, receiving the packet communications from the interworking
units, routing the packet communications over the optical
communication paths based on the interworking information in the
headers, receiving the routed packet communications from the
optical communication paths, and transferring the routed packet
communications to the interworking units; and in the interworking
units, receiving the second control messages and the routed packet
communications, and in response, converting the routed packet
communications into the user communications and transferring the
user communications.
12. The method of claim 11 wherein the packet communications
comprise asynchronous transfer mode communications.
13. The method of claim 11 wherein the communications devices
comprise asynchronous transfer mode devices.
14. The method of claim 11 wherein the user communications comprise
time division multiplex communications.
15. The method of claim 11 wherein the user communications comprise
analog voice communications.
16. The method of claim 11 wherein the signaling comprises
broadband signaling.
17. The method of claim 11 wherein the signaling comprises
Signaling System Seven (SS7) signaling.
18. The method of claim 11 wherein the signaling comprises initial
address messages.
19. The method of claim 11 wherein the signaling comprises
Integrated Service Digital Network (ISDN) signaling.
20. The method of claim 11 wherein the optical communication paths
comprise Synchronous Optical Network (SONET) paths.
Description
RELATED APPLICATIONS
[0001] This patent application is a continuation of patent
application Ser. No. 09/642,722; filed Aug. 21, 2000; entitled
"System and Method For Connecting A Call;" and which is a
continuation of U.S. Pat. No. 6,137,800; filed on May 9, 1997;
entitled "System and Method For Connecting A Call;" and which is
hereby incorporated by reference into this patent application.
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
MICROFICHE APPENDIX
[0003] Not Applicable
FIELD OF THE INVENTION
[0004] The present invention relates to the field of
telecommunications call switching and transport.
BACKGROUND OF THE INVENTION
[0005] Broadband systems are being developed and implemented.
Broadband systems provide telecommunications providers with many
benefits, including greater bandwidth, more efficient use of
bandwidth, and the ability to integrate voice, data, and video
communications. These broadband systems provide callers with
increased capabilities at lower costs.
[0006] Switches and other communication devices use broadband
systems, such as a synchronous optical network (SONET) ring or a
synchronous digital hierarchy (SDH) system, to connect calls to
other switches and communication devices. The switches, for
example, determine how a call is to be connected and control the
switching over the broadband system. In addition, switches, such as
tandem switches, are used to concentrate telecommunication traffic
between networks, switches, and other communication devices.
[0007] However, controlling call switching and connection functions
from switches and some other communication devices is expensive.
Moreover, intelligent network routing and processing functions are
limited. In addition, conventional switching systems do not provide
highly efficient call concentration and call routing in networks
such as metropolitan area networks (MANs). Therefore, there is a
need for a system that more efficiently and more easily provides
connections for switches and other communications devices over
broadband networks, such as the SONET ring or the SDH system. An
effective system is needed that can control switching and call
connections between system devices on a call-by-call basis in an
asynchronous transfer mode (ATM) environment.
SUMMARY OF THE INVENTION
[0008] Examples of the invention include a communication system
comprising a plurality of signaling processors, a plurality of
interworking units linked to the signaling processor, a plurality
of optical communication paths, and a plurality of communication
devices coupled to the interworking units. Each pair of the
communication devices are coupled together by one of the optical
communication paths to form a flat architecture between the
communication devices. The signaling processors are configured to
receive and process signaling, and in response, to generate and
transfer first control messages and second control messages
indicating interworking information. The interworking units are
configured to receive the first control messages and user
communications, and in response, to convert the user communications
into packet communications having the interworking information in
headers of the packet communications and transfer the packet
communications to the communication devices. The communication
devices are configured to receive the packet communications from
the interworking units and route the packet communications over the
optical communication paths based on the interworking information
in the headers. The communication devices are configured to receive
the routed packet communications from the optical communication
paths and transfer the routed packet communications to the
interworking units. The interworking units are configured to
receive the second control messages and the routed packet
communications, and in response, to convert the routed packet
communications into the user communications and transfer the user
communications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a block diagram of a broadband metropolitan area
network with a plurality of broadband interfaces of the present
invention.
[0010] FIG. 2 is a block diagram of components of a first broadband
interface and components of a second broadband interface.
[0011] FIG. 3 is a block diagram of a broadband interface in which
multiple interworking units are attached to a cross connect.
[0012] FIG. 4 is a block diagram of a broadband metropolitan area
network with a plurality of broadband interfaces each attached to a
signaling processor which communicates with a signal transfer
point.
[0013] FIG. 5 is a functional diagram of an asynchronous transfer
mode interworking unit for use with a synchronous optical network
system in accordance with the present invention.
[0014] FIG. 6 is a functional diagram of an asynchronous transfer
mode interworking unit for use with a synchronous digital hierarchy
system in accordance with the present invention.
[0015] FIG. 7 is a block diagram of a signaling processor
constructed in accordance with the present system.
[0016] FIG. 8 is a block diagram of a data structure having tables
that are used in the signaling processor of FIG. 7.
[0017] FIG. 9 is a block diagram of additional tables that are used
in the signaling processor of FIG. 7.
[0018] FIG. 10 is a table diagram of a trunk circuit table used in
the signaling processor of FIG. 7.
[0019] FIG. 11 is a table diagram of a trunk group table used in
the signaling processor of FIG. 7.
[0020] FIG. 12 is a table diagram of an exception circuit table
used in the signaling processor of FIG. 7.
[0021] FIG. 13 is a table diagram of an automated number index
table used in the signaling processor of FIG. 7.
[0022] FIG. 14 is a table diagram of a called number table used in
the signaling processor of FIG. 7.
[0023] FIG. 15 is a table diagram of a routing table used in the
signaling processor of FIG. 7.
[0024] FIG. 16 is a table diagram of a treatment table used in the
signaling processor of FIG. 7.
[0025] FIG. 17 is a table diagram of a message table used in the
signaling processor of FIG. 7.
DETAILED DESCRIPTION
[0026] Telecommunication systems have a number of communication
devices in local exchange and interexchange environments that
interact to provide call services to customers. Both traditional
services and resources and intelligent network (IN) services and
resources are used to process, route, or connect a call to a
designated connection.
[0027] A call has call signaling and user communications. The user
communications contain the caller's information, such as a voice
communication or data communication, and they are communicated over
a connection. Call signaling contains information that facilitates
call processing, and it is communicated over a link. Call
signaling, for example, contains information describing the called
number and the calling number. Examples of call signaling are
standardized signaling, such as signaling system #7 (SS7), C7,
integrated services digital network (ISDN), and digital private
network signaling system (DPNSS), which are based on ITU
recommendation Q.933.
[0028] A call can be transported to or from a communication device.
A communication device can be, for example, customer premises
equipment (CPE), a service platform, a switch, or any other device
capable of initiating, handling, or terminating a call. Customer
premises equipment can be, for example, a telephone, a computer, a
facsimile machine, or a private branch exchange. A service platform
can be, for example, a service platform or any other enhanced
platform that is capable of processing calls.
[0029] Communications devices in both traditional and intelligent
systems can use a variety of protocols and methods to achieve a
connection for a call or to complete call processing. For example,
CPE can be connected to a switch using a time division multiplex
(TDM) format, such as super frame (SF) or extended superframe
(ESF). The ESF connection allows multiple devices at the customer
site to access the local switch and obtain telecommunication
services.
[0030] Also, communication devices, such as telephones, are likely
connected to a remote digital terminal, and the connection
typically carries analog signals over twisted pair wires. The
remote digital terminals provide a digital interface between the
telephones and a local switch by converting the analog signals from
the telephones into a multiplexed digital signal to be transferred
to the local switch. A common standard for the connection between
the remote digital terminal and the local switch is provided in
Bellcore Reference GR-TSY-000303 (GR-303).
[0031] In addition, communications devices use broadband protocols,
such as broadband-integrated services digital network (B-ISDN).
Broadband systems provide greater bandwidth than narrowband systems
for calls, in addition to providing digital processing of the
calls. B-ISDN provides a communication device with a digital
connection to a local switch or other device. The B-ISDN loop
provides more bandwidth and control than a convention local loop.
The European implementation of B-ISDN and other broadband protocols
can also be used.
[0032] Communication devices can use circuit-based connections for
calls. For example, digital signal (DS) level communications, such
as digital signal level 3 (DS3), digital signal level one (DS1),
and digital signal level zero (DS0) are conventional circuit-based
connections. European level four (E4), European level three (E3),
European level one (E1), European level zero (E0), and other
European equivalent circuit-based connections also are used.
[0033] High speed electrical/optical transmission protocols also
are used by communications devices for switching and signaling. The
synchronous optical network (SONET) protocol, which is used
primarily in North America, and the synchronous digital hierarchy
(SDH) protocol, which is used primarily in Europe, are examples of
high speed electrical/optical protocols. The SONET and SDH
protocols describe the physical media and transmission protocols
through which the communications take place.
[0034] The SONET and SDH protocols define a broadband frame
structure for SONET and SDH communication signals. Multiple frames
travel in the communication signals. Each frame consists of
overhead and payload. The overhead contains operations,
administration, maintenance, and provisioning information, such as
framing information, error correction information, and pointer
information. The payload contains the user communications
information that is carried in the frame by the communication
signal. The payload is comprised of payload components that are
mapped into the frames. For example, user communications from a
DS1, an E1, or an asynchronous transfer mode (ATM) connection may
be mapped into the broadband frames. Thus, in a SONET system, the
user communications are mapped to SONET frames. In an SDH system,
user communications are mapped to SDH frames.
[0035] SONET includes optical transmission of optical carrier (OC)
signals and electrical transmission of synchronous transport
signals (STSs). SONET signals transmit at a base rate of 51.84
Mega-bits per second (Mbps) for optical carrier level one (OC-1)
and synchronous transport signal level one (STS-1). Also
transmitted are multiples thereof, such as an STS level three
(STS-3) and an OC level three (OC-3) at rates of 155.52 Mbps, an
STS level twelve (STS-12) and an OC level twelve (OC-12) at rates
of 622.08 Mbps, an STS level forty-eight (STS-48) and an OC level
forty-eight (OC-48) at rates of 2,488.32 Mbps, and fractions
thereof, such as a virtual tributary group (VTG) at a rate of 6.912
Mbps.
[0036] SDH includes transmission of optical synchronous transport
module (STM O) signals and electrical synchronous transport module
(STM E) signals. SDH signals transmit at a base rate of 155.52 Mbps
for synchronous transport module level one electrical and optical
(STM-1 E/O). Also transmitted are multiples thereof, such as an STM
level four electrical/optical (STM-4 E/O) at rates of 622.08 Mbps,
an STM level sixteen electrical/optical (STM-16 E/O) at rates of
2,488.32 Mbps, and fractions thereof, such as a tributary unit
group (TUG) at a rate of 6.912 Mbps.
[0037] ATM is one technology that is being used in conjunction with
SONET and SDH to provide broadband call switching and call
transport for telecommunication services. ATM is a protocol that
describes communication of user communications in ATM cells.
Because cells are used in the protocol, calls can be transported on
demand for connection-oriented traffic or connectionless-oriented
traffic, constant-bit traffic or variable-bit traffic, and between
equipment that either requires timing or does not require
timing.
[0038] Some ATM systems handle calls over switched virtual paths
(SVPs) and switched virtual circuits (SVCs). The virtual nature of
ATM allows multiple communication devices to use a physical
communication line at different times. This type of virtual
connection more efficiently uses bandwidth, and thereby provides
more cost efficient transport for customer calls, than permanent
virtual circuits (PVCs) or other dedicated circuits.
[0039] The ATM system is able to connect a caller from an
origination point to a destination point by selecting a connection
from the origination point to the destination point. The connection
contains a virtual path (VP) and a virtual channel (VC). A VC is a
logical connection between two end points for the transfer of ATM
cells. A VP is a logical combination of VCs. The ATM system
designates the selected connection by specifying a virtual path
identifier (VPI) that identifies the selected VP and a virtual
channel identifier (VCI) that identifies the selected VC within the
selected VP. Because many ATM connections are uni-directional,
bi-directional communications in an ATM system usually require
companion VPIs/VCIs.
[0040] An ATM system may be configured to transmit ATM cells over a
SONET broadband system or an SDH broadband system. The ATM cells
are mapped into the payload of the SONET frames or the SDH frames
and transported over a broadband path, such as a SONET pipe or an
SDH pipe. Typically the SONET and SDH systems are configured in a
ring topology that can provide redundant and alternate transmission
paths for calls.
[0041] The present invention efficiently and easily provides
connections and switching for switches and other communication
devices over a broadband system. The present invention provides
call connections by using ATM over a SONET broadband system or an
SDH broadband system. The ATM system provides robust switching
functions at an affordable cost.
[0042] FIG. 1 illustrates the broadband system 102 of the present
invention. The broadband system 102 concentrates and switches
telecommunication call traffic between networks, switches, and
elements of the broadband system. The broadband system 102 allows
switches and other communication devices to connect to each other
without a direct connection between each switch and communication
device. The broadband system 102 may be, for example, a broadband
metropolitan area network (BMAN).
[0043] The broadband system 102 comprises a signaling processor 104
and a plurality of broadband interfaces, such as a first broadband
interface 106, a second broadband interface 108, a third broadband
interface 110, a fourth broadband interface 112, a fifth broadband
interface 114, and a sixth broadband interface 116. It will be
appreciated that the broadband system 102 may have a greater or a
fewer number of broadband interfaces.
[0044] The broadband interfaces 106, 108, 110, 112, 114, and 116
are connected through a series of connections. Thus, the first
broadband interface 106 is connected to the second broadband
interface 108 through a connection 118. The second broadband
interface 108 is connected to the third broadband interface 110
through a connection 120. The third broadband interface 110 is
connected to the fourth broadband interface 112 through a
connection 122. The fourth broadband interface 112 is connected to
the fifth broadband interface 114 through a connection 124. The
fifth broadband interface 114 is connected to the sixth broadband
interface 116 through a connection 126. The sixth broadband
interface 116 is connected to the first broadband interface 106
through a connection 128. The broadband interfaces 106, 108, 110,
112, 114, and 116 and the connections 118, 129, 122, 124, 126, and
128 form a broadband ring. Each of the broadband interfaces 106,
108, 110, 112, 114, and 116 is linked to the signaling processor
104 through a link 130, 132, 134, 136, 138, and 140,
respectively.
[0045] Any broadband interface may reach any other broadband
interface in the broadband ring. For example, the first broadband
interface 106 may connect to the fifth broadband interface 114 by
connecting through the connection 128, the sixth broadband
interface 116, and the connection 126.
[0046] Typically, the connections 118, 120, 122, 124, 126, and 128
are ATM VPIs/VCIs connections that are provisioned over SONET or
SDH broadband paths. For example, the connections 118, 120, 122,
124, 126, and 128 may be VPIs/VCIs that are provisioned over OC-48
pipes. The broadband interfaces 106, 108, 110, 112, 114, and 116
and the SONET or SDH broadband paths containing the provisioned
virtual connections 118, 120, 122, 124, 126, and 128 form a SONET
ring or an SDH ring.
[0047] Each of the broadband interfaces 106, 108, 110, 112, 114,
and 116 may be connected to a switch or to another communication
device. In the broadband system 102 of the present invention, the
first broadband interface 108 is connected to a first communication
device 142 through a connection 144. The second broadband interface
108 is connected to a second communication device 146 through a
connection 148. The third broadband interface 110 is connected to a
first interexchange carrier (IXC) 150 through a connection 152. The
fourth broadband interface 112 is connected to an incumbent local
exchange carrier (ILEC) 154 through a connection 156. The fifth
broadband interface 114 is connected to a competitive local
exchange carrier (CLEC) 158 through a connection 160. The sixth
broadband interface 116 is connected to a second IXC 162 through a
connection 164. The signaling processor 104 is linked to the first
communication device 142 through a link 166, to the second
communication device 144 through a link 168, to the first IXC 150
through a link 170, to the ILEC 154 through a link 172, to the CLEC
158 through a link 174, and to the second IXC 162 through a link
176.
[0048] The connections 144, 148, 156, and 160 may be any connection
that carries circuit-based traffic. Typically, these are time
division multiplex (TDM) connections, such as DS3 or DS1
connections. Typically, the common DS0 used for traditional voice
calls is embedded within the DS3 or DS 1. The connections 152 and
164 may be either TDM connections, such as DS3 or DS1 connections,
or broadband path connections, such as OC-48 connections that carry
ATM traffic.
[0049] Connections are used to transport user communications and
other device information between communication devices and between
the elements and devices of the broadband system 102. The term
"connection" as used herein means the transmission media used to
carry user communications between the elements of the broadband
system 102 or between the broadband system 102 and other
communication devices and elements. For example, a connection could
carry a user's voice, computer data, or other communication device
data. A connection can be associated with either in-band
communications or out-of-band communications.
[0050] Links are used to transport call signaling and control
messages. The term "link" as used herein means a transmission media
used to carry call signaling and control messages. For example, a
link would carry call signaling or a device control message
containing device instructions and data. A link can carry, for
example, out-of-band signaling such as SS7, C7, ISDN, B-ISDN,
GR-303, local area network (LAN), or data bus call signaling. A
link can be, for example, an AAL5 data link, UDP/IP, Ethernet, or
DS0 over T1. In addition, a link, as shown in the figures, can
represent a single physical link or multiple links, such as one
link or a combination of links of ISDN, SS7, TCP/IP, or some other
data link. The term "control message" as used herein means a
control or signaling message, a control or signaling instruction,
or a control or signaling signal, whether proprietary or
standardized, that conveys information from one point to
another.
[0051] Those skilled in the art are aware that large networks have
many more components than those that are shown in FIG. 1. For
example, there may typically be a multitude of switches and
communication devices connected through the broadband system 102.
Those skilled in the art will appreciate that a signal transfer
point (STP) may be used to transfer signaling among the various
components. The number of components shown on FIG. 1 has been
restricted for clarity. The invention is fully applicable to a
large network or a small network.
[0052] The signaling processor 104 is a signaling platform that can
receive and process signaling. Based on the processed signaling,
the signaling processor 164 selects processing options,
connections, or resources for the user communications and generates
and transmits control messages that identify the communication
device, processing option, service, or resource that is to be used.
The signaling processor 104 also selects virtual connections and
circuit-based connections for call routing and generates and
transports control messages that identify the selected connections.
The signaling processor 104 can process various forms of signaling,
including ISDN, SS7, and C7. A preferred signaling processor is
discussed in detail below.
[0053] The broadband interfaces 106, 108, 110, 112, 114, and 116
transport telecommunication traffic between circuit-based
connections and virtual connections, between circuit-based
connections and other circuit-based connections, or between virtual
connections and other virtual connections. The broadband interfaces
106, 108, 110, 112, 114, and 116 place telecommunication traffic
onto the broadband paths of the broadband system 102 and take
telecommunication traffic from the broadband paths of the broadband
system. Likewise, the broadband interfaces 106, 108, 110, 112, 114,
and 116 receive telecommunication traffic from circuit-based
systems and transfer telecommunication traffic to circuit-based
systems.
[0054] The broadband interfaces 106, 108, 110, 112, 114, and 116
provide switching and intelligent network functions for calls. For
example, the broadband interfaces 106, 108, 110, 112, 114, and 116,
together with the signaling processor 104, connect calls from one
communication device to another communication device.
[0055] The communication devices 142 and 146 each comprise CPE, a
service platform, a switch, a remote digital terminal, or any other
device capable of initiating, handling, or terminating a call. CPE
can be, for example, a telephone, a computer, a facsimile machine,
or a private branch exchange. A service platform can be, for
example, a service platform or any other enhanced platform that is
capable of processing calls. A remote digital terminal is a device
that concentrates analog twisted pairs from telephones and other
like devices and converts the analog signals to a digital format
known as GR-303.
[0056] The first and second IXCs 150 and 162 comprise communication
devices that can transport, receive, and handle calls. The first
and second IXCs 150 and 162 may be connected to other IXCs, local
exchange carriers (LECs), or other communication devices.
[0057] The ILEC 154 and the CLEC 158 each comprise switches that
transport, receive, and handle calls. The ILEC 154 is an
established local network. The CLEC 158 is a newer local network
that is allowed to compete with the established local network. The
ILEC 154 and the CLEC 158 may be, for example, class 4 tandem
switches, class 5 switches, or class 4/5 switches. The switches
shown on FIG. 1 are well known circuit switches with examples being
the Nortel DMS-250 or the Lucent 5ESS.
[0058] The system of FIG. 1 operates as follows for a call that is
transported between the CLEC 158 and the ILEC 154 through a SONET
ring. The CLEC 158 transports call signaling to the signaling
processor 104 over the link 174 and transports user communications
in a TDM format to the fifth broadband interface 114 over the
connection 160.
[0059] The signaling processor 104 receives the call signaling and
processes the call signaling to determine connections for the call.
The signaling processor 104 selects a first connection 124 and a
second connection 156. The selected first connection 124 is a
SONET/ATM connection having an ATM VPI/VCI virtual connection that
is provisioned over a SONET OC level broadband path on the SONET
ring between the fourth broadband interface 112 and the fifth
broadband interface 114. For example, the selected first connection
may be a VPI/VCI provisioned over an OC-48 span. The selected
second connection 156 is a TDM connection. The signaling processor
104 transports a control message over the link 138 to the fifth
broadband interface 114 identifying the selected first connection
124. The signaling processor 104 also transmits a control message
over the link 136 to the fourth broadband interface 112 identifying
the selected second connection 156.
[0060] The fifth broadband interface 114 receives the control
message from the signaling processor 104 and the user
communications from the CLEC 158. The fifth broadband interface 114
converts the TDM formatted user communications to ATM cells that
identify the selected first connection 124 and maps the ATM cells
to SONET frames. The fifth broadband interface 114 places the SONET
frames on the virtual connection of the designated SONET path for
the selected first connection 124 so that they are transported to
the fourth broadband interface 112 over the SONET ring.
[0061] The fourth broadband interface 112 receives the control
message from the signaling processor 104 and receives the SONET
frames over the selected first connection 124. The fourth broadband
interface 112 drops the SONET frames from the SONET ring and then
maps the SONET frames to the ATM cells. The fourth broadband
interface 112 converts the ATM cells to TDM formatted user
communications and transports the user communications to the ILEC
154 over the selected second connection 156.
[0062] It will be appreciated that a call may be connected from the
ILEC 154 and to the CLEC 158 in the same manner. Alternatively, a
call may be connected between the ILEC 154 and the first IXC 105,
the ILEC 154 and the second communication device 146, or the ILEC
154 and the first communication device 142. In fact, a call may be
connected between any of the elements in the broadband system
102.
[0063] FIG. 2 illustrates the components of the first broadband
interface 106 and the second broadband interface 108. The first
broadband interface 106 and the second broadband interface 108 are
representative of broadband interfaces in the broadband system
102.
[0064] The first broadband interface 106 is comprised of a first
interworking unit 202, a first cross connect 204, and a first ring
terminal, such as a first add/drop multiplexer (ADM) 206. The first
cross connect 204 is connected to the first interworking unit 202
through a connection 208 and to the first ADM 206 through a
connection 210.
[0065] The first interworking unit 202 interworks traffic between
various protocols. Preferably, the first interworking unit 202
interworks between ATM traffic and non-ATM traffic. The first
interworking unit 202 operates in accordance with control messages
received from the signaling processor 104 over the link 130. These
control messages are typically provided on a call-by-call basis and
typically identify an assignment between a DS0 and a VPI/VCI for
which user communications are interworked.
[0066] Thus, the first interworking unit 202 converts TDM formatted
user communications to ATM cells that identify virtual connections
selected by the signaling processor 104. The first interworking
unit 202 maps ATM cells to broadband frames, such as SONET frames.
In addition, the first interworking unit 202 also maps broadband
frames, such as SONET frames, to ATM cells. The first interworking
unit 202 converts the ATM cells to TDM formatted user
communications. In some instances, the first interworking unit 202
may transport control messages which may include data to the
signaling processor 104.
[0067] In some embodiments, the first interworking unit 202 is
operational to implement digital signal processing as instructed in
the control messages. An example of digital signal processing is
echo cancellation or continuity testing. A preferred embodiment of
the first interworking unit 202 is discussed in detail below.
[0068] The first cross connect 204 is any device, such as an ATM
cross connect, that provisions virtual connections over broadband
paths, such as ATM connections over SONET paths in a SONET ring.
The first cross connect 204 provides a plurality of ATM virtual
connections between the first ADM 206 and the first interworking
unit 202. In ATM, virtual connections are designated by the VPI/VCI
in the cell header. The first cross connect 204 is configured to
accept ATM cells from, and transport ATM cells to, the first
interworking unit 202 and to provide a plurality of VPI/VCI
connections to the first ADM 206.
[0069] The VCIs are used to differentiate individual calls on the
VPI between the first cross connect 204 and the first ADM 206 and
to identify the destination or handling point of the call. For
example, VPI/VCI "A" may be provisioned from the first interworking
unit 202, through the first cross connect 204, through the first
ADM 206, and "destined" for an interworking unit connected to a
cross connect in the second broadband interface 108 that is
associated with the second communication device 146. VPI/VCI "B"
may be provisioned from the first interworking unit 202, through
the first cross connect 204, through the first ADM 206, and
"destined" for an interworking unit connected to a cross connect in
the fourth broadband interface 112 that is associated with the ILEC
154. (See FIG. 1.) An example of an ATM cross connect is the NEC
Model 20.
[0070] The first cross connect 204 provisions the connections from
the first interworking unit 202, through the first ADM 206, and to
another cross connect and from another cross connect, through the
first ADM, and to the first interworking unit. In a SONET system,
the first cross connect 204 receives SONET frames containing mapped
ATM cells from the first ADM 206 and cross connects the SONET
frames on the connection to the first interworking unit 202. In
addition, in a SONET system, the first cross connect 204 receives
SONET frames containing mapped ATM cells from the first
interworking unit 202 and cross connects the SONET frames on the
designated VPI/VCI virtual connection to the first ADM 206.
[0071] The first ADM 206 adds traffic to the broadband paths of the
broadband ring for the connections 118 and 128 or drops traffic
from the broadband paths for the connections. The first ADM 206 may
add or drop traffic that is transported at levels extending from
the DS1 level to the OC level or the STS level and to equivalent
standards. The broadband paths for connections leading to and from
the first ADM 206, such as the connections 118 and 128, are
provisioned by the first ADM 206 as, for example, SONET paths to
all other communication devices in the broadband system 102. Thus,
for example, a SONET path is provisioned between the first ADM 206
in the first broadband interface 106 and an ADM in the second
broadband interface 108 to carry traffic for the virtual connection
for the connection 118. Another SONET path is provisioned between
the first ADM 206 in the first broadband interface 106 and an ADM
in the sixth broadband interface 116 to carry traffic for the
virtual connection for the connection 128. (See FIG. 1.)
[0072] Referring still to FIG. 2, the second broadband interface
108 is comprised of a second interworking unit 212, a second cross
connect 214, and a second ring terminal, such as a second add/drop
multiplexer (ADM) 216. The second cross connect 214 is connected to
the second interworking unit 212 through a connection 218 and to
the second ADM 206 through a connection 220.
[0073] The second interworking unit 212 interworks traffic between
various protocols. Preferably, the second interworking unit 212
interworks between ATM traffic and non-ATM traffic. The second
interworking unit 212 operates in accordance with control messages
received from the signaling processor 104 over the link 132. These
control messages are typically provided on a call-by-call basis and
typically identify an assignment between a DS0 and a VPI/VCI for
which user communications are interworked.
[0074] Thus, the second interworking unit 212 converts TDM
formatted user communications to ATM cells that identify virtual
connections selected by the signaling processor 104. The second
interworking unit 212 maps ATM cells to broadband frames, such as
SONET frames. In addition, the second interworking unit 212 also
maps broadband frames, such as SONET frames, to ATM cells. The
second interworking unit 212 converts ATM cells to TDM formatted
user communications. In some instances, the second interworking
unit 212 may transport control messages which may include data to
the signaling processor 104.
[0075] In some embodiments, the second interworking unit 212 is
operational to implement digital signal processing as instructed in
the control messages. An example of digital signal processing is
echo cancellation or continuity testing. A preferred embodiment of
the second interworking unit 212 is discussed in detail below.
[0076] The second cross connect 214 is any device, such as an ATM
cross connect, that provisions virtual connections over broadband
paths, such as ATM connections over a SONET ring. The second cross
connect 214 provides a plurality of ATM virtual connections between
the second ADM 216 and the second interworking unit 212. In ATM,
virtual connections are designated by the VPI/VCI in the cell
header. The second cross connect 214 is configured to accept ATM
cells from, and transport ATM cells to, the second interworking
unit 212 and to provide a plurality of VPI/VCI connections to the
second ADM 216.
[0077] The VCIs are used to differentiate individual calls on the
VPI between the second ADM 216 and the second interworking unit 212
and to identify the destination or handling point of the call. For
example, VPI/VCI "A" may be provisioned from the second
interworking unit 212, through the second cross connect 214,
through the second ADM 216, and "destined" for an interworking unit
connected to a cross connect in the first broadband interface 106
that is associated with the first communication device 142. VPI/VCI
"B" may be provisioned from the second interworking unit 212,
through the second cross connect 214, through the second ADM 216,
and "destined" for an interworking unit connected to a cross
connect in the fourth broadband interface 112 that is associated
with the ILEC 154. (See FIG. 1.) An example of an ATM cross connect
is the NEC Model 20.
[0078] The second cross connect 214 provisions the virtual
connections from the second interworking unit 212, through the
second ADM 216, and to other cross connects and from other cross
connects, through the ADM, and to the second interworking unit. In
a SONET system, the second cross connect 214 receives SONET frames
containing mapped ATM cells from the second ADM 216 and cross
connects the SONET frames on the connection to the second
interworking unit 212. In addition, in a SONET system, the second
cross connect 214 receives SONET frames containing mapped ATM cells
from the second interworking unit 212 and cross connects the SONET
frames on the designated virtual connection for the connection to
the second ADM 216.
[0079] The second ADM 216 adds traffic to the broadband paths of
the broadband ring for the connections 118 and 120 or drops traffic
from the broadband paths for the connections. The second ADM 216
may add or drop traffic that is transported at levels extending
from the DS1 level to the OC level or the STS level and equivalent
standards. The broadband paths for connections leading to and from
the second ADM 216, such as the connections 118 and 120, are
provisioned by the second ADM 216 as, for example, SONET paths to
all other communication devices in the broadband system 102. Thus,
for example, a SONET path is provisioned between the second ADM 216
in the second broadband interface 108 and the first ADM 206 in the
first broadband interface 106 to carry traffic for the virtual
connection for the connection 118. Another SONET path is
provisioned between the second ADM 216 in the second broadband
interface 108 and an ADM in the sixth broadband interface 116 to
carry traffic for the virtual connection for the connection 120.
(See FIG. 1.)
[0080] A broadband path in a SONET system is identified by a SONET
OC level or STS level path. Similarly, a virtual connection is
identified by an ATM VPI/VCI or companion ATM VPIs/VCIs. This
combination of the provisioned virtual connection in the
provisioned broadband path shall be referred to herein as the ATM
connection over the SONET path or as the virtual connection of the
broadband path. Thus, for example, the provisioned VPI/VCI between
the first interworking unit 202 and the second interworking unit
212, through the first cross connect 204 and the second cross
connect 214, which extends through the provisioned broadband path
of the SONET ring between the first ADM 206 and the second ADM 216
is referred to herein as the virtual connection over the broadband
path for the connection 118 or as the ATM connection of the SONET
ring for the connection 118.
[0081] It will be appreciated that the system described above may
be modified to incorporate various other carrier network and system
equipment. For example, in some cases, a terminal multiplexer or an
access multiplexer may be used instead of the add/drop multiplexer
of the preferred system described above.
[0082] The first broadband interface 106 and the second broadband
interface 108 of FIG. 2 operate as follows when the first
communication device 142 transports a call to the second
communication device 146 in a SONET broadband system 102. The
operation of the first broadband interface 106 and the second
broadband interface 108 are representative of the other broadband
interfaces 110, 112, 114, and 116.
[0083] Referring to FIG. 1, it will be understood that SONET paths
are provisioned from each broadband interface 106, 108, 110, 112,
114, and 116 to every other broadband interface in the broadband
network 102. For example, the fifth broadband interface 114 will
have a SONET path provisioned to every other broadband interface
106, 108, 110, 112, and 116. It will be appreciated that this forms
a flat architecture between the broadband interfaces 106, 108, 110,
112, 114, and 116 which is implemented over the SONET ring.
[0084] Referring to FIG. 1 and FIG. 2, the SONET paths are
provisioned between the ADMs in each broadband interface 106, 108,
110, 112, 114, and 116, such as between the first ADM 206 and the
second ADM 216. In a similar fashion, ATM connections are
provisioned between the cross connects of each broadband interface
106, 108, 110, 112, 114, and 116 to the cross connects in each
other broadband interface and to the associated interworking units.
For example, the first cross connect 204 in the first broadband
interface 106 uses the SONET paths provided by the ADM 206 to
provision an ATM connection from the first interworking unit 202
through the second cross connect 214 in the second broadband
interface 108 to the second interworking unit 212.
[0085] The interworking units of each of the broadband interfaces
106, 108, 110, 112, 114, and 116 have a provisioned ATM connection
over the SONET ring to each of the interworking units in the other
broadband interfaces. Thus, it can be seen that the first
interworking unit 202 in the first broadband interface 106 has a
provisioned ATM connection over the SONET ring to each of the
interworking units in the other broadband interfaces 108, 110, 112,
114, and 116. For example, the first interworking unit 202 in the
first broadband interface 106 has a provisioned ATM connection over
the SONET ring to the second interworking unit 212 in the second
broadband interface 108. Because the ATM connections are
provisioned over the SONET ring, when the signaling processor 104
selects a connection, an interworking unit places the ATM cells on
the selected connection, and the ATM cells are transported in the
broadband frames to the receiving interworking unit. It will be
appreciated that ATM connections may be provisioned over the SONET
ring prior to a call, and that ATM connections may be reprovisioned
over the SONET ring during or after a call.
[0086] When a call is transported, it must conform to both the ATM
protocol and the SONET protocol. The user communications are first
placed into ATM cells that identify the VPI/VCI of the selected
connection. This allows ATM capable communication devices to
transport calls to, and receive calls from, other ATM capable
communication devices. The ATM cells are then mapped into SONET
frames to be transported and received over the SONET paths.
Typically, the ATM cells are mapped to an OC-3 level or an STS-3c
level communication. It should be noted that, for clarity, ATM
cells that are mapped to SONET frames may be referred to below as
ATM cells, without the reference to the SONET frame mapping. One
skilled in the art will appreciate that ATM cells are mapped to and
from SONET frames at the first and second interworking units 202
and 212.
[0087] When a call is to be connected, the first communication
device 142 transports the call signaling to the signaling processor
104 over the link 166 in an appropriate format, such as SS7. The
first communication device 142 transports the user communications
to the first interworking unit 202 over the connection 144 in a
communication format, such as a TDM format over a DS0 embedded in a
DS3.
[0088] The signaling processor 104 receives the call signaling and
processes the call signaling to determine connections for the call.
The signaling processor 104 selects a first connection 118 over
which the ATM formatted user communications will be transported
from the first broadband interface 106. The selected first
connection 118 is an ATM connection over a SONET path, such as a
VPI/VCI in an OC-48 pipe. The signaling processor 104 transports a
control message over the link 130 to the first interworking unit
202. The control message identifies the selected first connection
118.
[0089] The signaling processor 104 also processes the call
signaling to determine a second connection 148 for the call over
which the second interworking unit 212 will transport TDM formatted
user communications to the second communication device 146. The
selected second connection 148 is a TDM connection, such as a DS0
embedded in a DS3. The signaling processor 104 transports a control
message over the link 132 to the second interworking unit 212. The
control message identifies the selected second connection 148.
[0090] The first interworking unit 202 receives the control message
from the signaling processor 104 and the user communications from
the first communication device 142. The first interworking unit 202
interworks the TDM formatted user communications to ATM cells that
identify the selected VPI/VCI of the first connection 118.
[0091] The ATM cells are mapped to SONET frames for the requisite
OC level or STS level communication. The first interworking unit
202 then transports the ATM cells in the SONET frames to the first
cross connect 204 over a connection 208. Preferably, the connection
is an OC-3.
[0092] The first cross connect 204 receives the SONET frames
containing the ATM cells. The first cross connect 204 removes the
ATM cells from the SONET frames and cross connects the ATM cells
through the ATM fabric to the appropriate provisioned virtual
connection for the selected first connection 118. The first cross
connect 204 maps the ATM cells back into SONET frames at the output
of the first cross connect. The SONET frames containing the ATM
cells are transported to the first ADM 206 over a provisioned path
in the connection 210 for the VPI/VCI of the selected first
connection 118. The connection 210 preferably is an OC level or an
STS level connection, such as an OC-3. It can be seen that cells
are transported to the correct connection when the correct VPI/VCI
is selected.
[0093] The first ADM 206 receives the SONET frames containing the
ATM cells from the first cross connect 204 over the connection 210.
The first ADM 206 adds the frames on the provisioned broadband path
on the SONET ring that has the corresponding provisioned VPI/VCI of
the selected first connection 118. The SONET frames are transported
over the SONET ring on, for example, an OC-48 to the second
broadband interface 108.
[0094] The second ADM 216 receives the SONET frames containing the
ATM cells over the selected first connection 118 of the SONET ring.
The second ADM 216 drops the SONET frames containing the ATM cells
from the SONET ring to the second cross connect 214.
[0095] The second cross connect 214 receives the SONET frames over
the connection 220. The second cross connect 214 cross connects the
SONET frames containing the ATM cells to the second interworking
unit 212 over the provisioned path in the connection 218 that
corresponds to the VPI/VCI in the ATM cells.
[0096] The second interworking unit 212 receives the SONET frames
from the second cross connect 214 and the control message from the
signaling processor 104. The second interworking unit 212 maps the
SONET frames to the ATM cells. The second interworking unit 212
converts the ATM cells to TDM formatted user communications and
transports the TDM formatted user communications to the second
communication device 146 over the selected second connection
148.
[0097] Referring still to FIG. 2, a call may be connected from the
second communication device 146 to the first communication device
142. The process for the connection and the transport of the user
communications is the same as described above, except that the
second broadband interface 108 transports the user communications
as ATM cells mapped in SONET frames and the first broadband
interface 106 receives the user communications as ATM cells mapped
in the SONET frames.
[0098] Although the system is described above using SONET
designations, the invention is equally applicable for use with SDH
systems. For example, ATM cells may be mapped to STM-1
electrical/optical (E/O) frames in the SDH system instead of
analogous STS-3c/OC-3 frames in a SONET system. Likewise, ATM cells
and lower SDH level communications may be multiplexed or mapped up
to STM-12 E/O communications in the SDH system instead of analogous
STS-48/OC-48 communications in a SONET system.
[0099] Referring to FIG. 1 and FIG. 2, it will be appreciated that
the functions of the signaling processor 104, the first
interworking unit 202, the first cross connect 204, and the first
ADM 206 provide switching-type functions for ATM traffic being
transported to communication devices in the SONET ring from the
first broadband interface 106. Moreover, the functions of the
signaling processor 104, the second interworking unit 212, the
second cross connect 214, and the second ADM 216 provide
switching-type functions for traffic being transported to
communication devices, such as switches, from the SONET ring.
[0100] These switching functions give the broadband system 102 the
ability to connect and switch calls to any location in the
broadband system 102. This allows the broadband system to complete
such functions as local number portability so that a telephone
service customer can switch services from, for example, the ILEC
154 to the CLEC 158 and keep the same local telephone number. Other
services, including intelligent network services, also may be
provided.
[0101] The present invention as explained above may be adapted for
use with other devices or with fewer devices. For example, the
first broadband interface 106 may be adapted to be used without the
cross connect 204. However, some switching functionality may be
eliminated because broadband paths then would be provisioned to the
first interworking unit 202, and the first interworking unit would
have to select the broadband path. Multiple SONET paths may be
provisioned from the first interworking unit 202 to each call
destination.
[0102] As illustrated in FIG. 3, the broadband interface 302 may
have multiple interworking units or cross connects. Thus, a cross
connect 304 may be connected to a first interworking unit 306 and
to a second interworking unit 308, in addition to an ADM 310. A
signaling processor 312 processes call signaling and determines
connections and processing for the components of the broadband
interface 302. The first and second interworking units 306 and 308
may be in the same proximate location or in different proximate
locations. Moreover, the cross connect 304 or other components may
be connected to another cross connect or to a gateway (not
shown).
[0103] As illustrated in FIG. 4, the broadband system 102B may use
an STP 404. In addition, the broadband system 102B may be
configured so that a plurality of broadband interfaces are each
connected to its own signaling processor. In this configuration,
the broadband system 102B has a first broadband interface 404
linked to a first signaling processor 406, a second broadband
interface 408 linked to a second signaling processor 410, a third
broadband interface 412 linked to a third signaling processor 414,
a fourth broadband interface 416 linked to a fourth signaling
processor 418, a fifth broadband interface 420 linked to a fifth
signaling processor 422, and a sixth broadband interface 424 linked
to a sixth signaling processor 426. Each of the signaling
processors 406, 410, 414, 418, 422, and 426 are linked to the STP
402. For clarity, the links and the connections are not
referenced.
[0104] In addition, it will be appreciated that the system of the
present invention may connect calls for a variety of communication
devices. For example, a broadband interface may be connected to a
class 4 switch, a class 5 switch, or a class 4/5 switch. These
switches may, in turn, be connected to other class 4, class 5, or
class 4/5 switches. The broadband system and broadband interfaces
may be used to connect and process calls in a local architecture or
in an interexchange architecture. In addition, the broadband system
and broadband interfaces may be used to connect and process calls
in facility based and non-facility based traffic. Moreover, the
broadband interfaces may connect to in-band signaling communication
devices as well as the out-of-band signaling communication
devices.
[0105] The ATM Interworking Unit
[0106] FIG. 5 shows one embodiment of an interworking unit which is
an ATM interworking unit 502 suitable for the present invention for
use with a SONET system, but other interworking units that support
the requirements of the invention are also applicable. The ATM
interworking unit 502 may receive and transmit in-band and
out-of-band calls.
[0107] The ATM interworking unit 502 has a control interface 504,
an OC-N/STS-N interface 506, a DS3 interface 508, a DS1 interface
510, a DS0 interface 512, a signal processor 514, an ATM adaptation
layer (AAL) 516, an OC-M/STS-M interface 518, and an ISDN/GR-303
interface 520. As used herein in conjunction with OC or STS, "N"
refers to an integer, and "M" refers to an integer.
[0108] The control interface 504 accepts control messages from the
signaling processor 522. In particular, the control interface 504
identifies DS0 connections and virtual connection assignments in
the control messages from the signaling processor 522. These
assignments are provided to the AAL 516 for implementation.
[0109] The OC-N/STS-N interface 506, the DS3 interface 508, the DS1
interface 510, the DS0 interface 512, and the ISDN/GR-303 interface
520 each can accept calls, including user communications, from a
communication device 524. Likewise, the OC-M/STS-M interface 518
can accept calls, including user communications, from a
communication device 526.
[0110] The OC-N/STS-N interface 506 accepts OC-N formatted calls
and STS-N formatted calls and converts the calls from the OC-N or
STS-N formats to the DS3 format. The DS3 interface 508 accepts
calls in the DS3 format and converts the calls to the DS1 format.
The DS3 interface 508 can accept DS3s from the OC-N/STS-N interface
506 or from an external connection. The DS1 interface 510 accepts
the calls in the DS1 format and converts the calls to the DS0
format. The DS1 interface 510 can accept DS1s from the DS3
interface 508 or from an external connection. The DS0 interface 512
accepts calls in the DS0 format and provides an interface to the
AAL 516. The ISDN/GR-303 interface 520 accepts calls in either the
ISDN format or the GR-303 format and converts the calls to the DS0
format. In addition, each interface may transmit signals in like
manner to the communication device 524.
[0111] The OC-M/STS-M interface 518 is operational to accept ATM
cells from the AAL 516 and to transmit the ATM cells over the
connection to the communication device 526. The OC-M/STS-M
interface 518 may also accept ATM cells in the OC or STS format and
transmit them to the AAL 516.
[0112] The AAL 516 comprises both a convergence sublayer and a
segmentation and reassembly (SAR) sublayer. The AAL 516 is
operational to accept communication device information in the DS0
format from the DS0 interface 512 and to convert the communication
device information into ATM cells. AALs are known in the art and
information about AALs is provided by International
Telecommunications Union (ITU) document I.363, which is
incorporated fully herein by reference. An AAL for voice calls is
described in U.S. patent application Ser. No. 08/395,745, which was
filed on Feb. 28, 1995, and entitled "Cell Processing for Voice
Transmission," and which is incorporated herein by reference.
[0113] The AAL 516 obtains from the control interface 504 the
virtual path identifier (VPI) and the virtual channel identifier
(VCI) for each DS0 for each call connection. The AAL 516 also
obtains the identity of the DS0 for each call (or the DS0s for an
N.times.64 call). The AAL 516 then transfers the communication
device information between the identified DS0 and the identified
ATM virtual connection. An acknowledgment that the assignments have
been implemented may be sent to the signaling processor 522 if
desired. Calls with multiple 64 Kilo-bits per second (Kbps) DS0s
are known as N.times.64 calls. If desired, the AAL 516 can be
configured to accept control messages through the control interface
504 for N.times.64 calls.
[0114] As discussed above, the ATM interworking unit 502 also
handles calls in the opposite direction, that is, in the direction
from the OC-M/STS-M interface 518 to the DS0 interface 512,
including calls exiting from the DS1 interface 510, the DS3
interface 508, the OC-N/STS-N interface 506, and the ISDN/GR-303
interface 520. For this traffic, the VPI/VCI has been selected
already and the traffic has been routed through the cross-connect
(not shown). As a result, the AAL 516 only needs to identify the
pre-assigned DS0 for the selected VPI/VCI. This can be accomplished
through a look-up table. In alternative embodiments, the signaling
processor 522 can provide this DS0-VPI/VCI assignment through the
control interface 504 to the AAL 516.
[0115] A technique for processing VPI/VCIs is disclosed in U.S.
patent application Ser. No. 08/653,852, which was filed on May 28,
1996, and entitled "Telecommunications System with a Connection
Processing System," and which is incorporated herein by
reference.
[0116] DS0 connections are bi-directional and ATM connections are
typically uni-directional. As a result, two virtual connections in
opposing directions typically will be required for each DS0. Those
skilled in the art will appreciate how this can be accomplished in
the context of the invention. For example, the cross-connect can be
provisioned with a second set of VPI/VCIs in the opposite direction
as the original set of VPI/VCIs. For each call, ATM interworking
multiplexers would be configured to invoke automatically this
second VPI/VCI to provide a bi-directional virtual connection to
match the bi-directional DS0 on the call.
[0117] In some embodiments, it may be desirable to incorporate
digital signal processing capabilities at the DS0 level. It may
also be desired to apply echo cancellation to selected DS0
circuits. In these embodiments, a signal processor 514 would be
included either separately (as shown) or as a part of the DS0
interface 512. The signaling processor 522 would be configured to
send control messages to the ATM interworking unit 502 to implement
particular features on particular DS0 circuits. Alternatively,
lookup tables may be used to implement particular features for
particular circuits or VPIs/VCIs.
[0118] FIG. 6 shows another embodiment of an interworking unit
which is an ATM interworking unit 602 suitable for the present
invention. The ATM interworking unit 502 may receive and transmit
in-band and out-of-band calls.
[0119] The ATM interworking unit 602 is for use with an SDH system
and has a control interface 604, an STM-N electrical/optical (E/O)
interface 606, an E3 interface 608, an E1 interface 610, an E0
interface 612, a signal processor 614, an ATM adaptation layer
(AAL) 616, an STM-M electrical/optical (E/O) interface 618, and a
digital private network signaling system (DPNSS) interface 620. As
used herein in conjunction with STM, "N" refers to an integer, and
"M" refers to an integer.
[0120] The control interface 604 accepts control messages from the
signaling processor 622. In particular, the control interface 604
identifies E0 connections and virtual connection assignments in the
control messages from the signaling processor 622. These
assignments are provided to the AAL 616 for implementation.
[0121] The STM-N E/O interface 606, the E3 interface 608, the E1
interface 610, the E0 interface 612, and the DPNSS interface 620
each can accept calls, including user communications, from a second
communication device 624. Likewise, the STM-M E/O interface 618 can
accept calls, including user communications, from a third
communication device 626.
[0122] The STM-N E/O interface 606 accepts STM-N electrical or
optical formatted calls and converts the calls from the STM-N
electrical or STM-N optical format to the E3 format. The E3
interface 608 accepts calls in the E3 format and converts the calls
to the E1 format. The E3 interface 608 can accept E3s from the
STM-N E/O interface 606 or from an external connection. The E1
interface 610 accepts the calls in the E1 format and converts the
calls to the E0 format. The E1 interface 610 can accept E1s from
the STM-N E/O interface 606 or the E3 interface 608 or from an
external connection. The E0 interface 612 accepts calls in the E0
format and provides an interface to the AAL 616. The DPNSS
interface 620 accepts calls in the DPNSS format and converts the
calls to the E0 format. In addition, each interface may transmit
signals in a like manner to the communication device 624.
[0123] The STM-M E/O interface 618 is operational to accept ATM
cells from the AAL 616 and to transmit the ATM cells over the
connection to the communication device 626. The STM-M E/O interface
618 may also accept ATM cells in the STM-M E/O format and transmit
them to the AAL 616.
[0124] The AAL 616 comprises both a convergence sublayer and a
segmentation and reassembly (SAR) sublayer. The AAL 616 is
operational to accept communication device information in the E0
format from the E0 interface 612 and to convert the communication
device information into ATM cells.
[0125] The AAL 616 obtains from the control interface 604 the
virtual path identifier and the virtual channel identifier for each
call connection. The AAL 616 also obtains the identity of each
call. The AAL 616 then transfers the communication device
information between the identified E0 and the identified ATM
virtual connection. An acknowledgment that the assignments have
been implemented may be sent back to the signaling processor 622 if
desired. If desired, the AAL 616 can be configured to accept
control messages through the control interface 604 for N.times.64
calls.
[0126] As discussed above, the ATM interworking unit 602 also
handles calls in the opposite direction, that is, in the direction
from the STM-M E/O interface 618 to the E0 interface 612, including
calls exiting from the E1 interface 610, the E3 interface 608, the
STM-N E/O interface 606, and the DPNSS interface 620. For this
traffic, the VPI/VCI has been selected already and the traffic has
been routed through the cross-connect (not shown). As a result, the
AAL 616 only needs to identify the pre-assigned E0 for the selected
VPI/VCI. This can be accomplished through a look-up table. In
alternative embodiments, the signaling processor 622 can provide
this VPI/VCI assignment through the control interface 604 to the
AAL 616.
[0127] E0 connections are bi-directional and ATM connections
typically are uni-directional. As a result, two virtual connections
in opposing directions typically will be required for each E0.
Those skilled in the art will appreciate how this can be
accomplished in the context of the invention. For example, the
cross-connect can be provisioned with a second set of VPI/VCIs in
the opposite direction as the original set of VPI/VCIs. For each
call, ATM interworking multiplexers would be configured to
automatically invoke this second VPI/VCI to provide a
bi-directional virtual connection to match the bi-directional E0 on
the call.
[0128] In some instances, it may be desirable to incorporate
digital signal processing capabilities at the E0 level. Also, it
may be desirable apply echo cancellation. In these embodiments, a
signal processor 614 would be included either separately (as shown)
or as a part of the E0 interface 612. The signaling processor 622
would be configured to send control messages to the ATM
interworking unit 602 to implement particular features on
particular circuits. Alternatively, lookup tables may be used to
implement particular features for particular circuits or
VPIs/VCIs.
[0129] The Signaling Processor
[0130] The signaling processor is referred to as a call/connection
manager (CCM), and it receives and processes telecommunications
call signaling and control messages to select connections that
establish communication paths for calls. In the preferred
embodiment, the CCM processes ISDN, GR-303, and SS7 signaling to
select connections for a call. CCM processing is described in a
U.S. Pat. No. 6,031,840 which is entitled "Telecommunication
System," which is assigned to the same assignee as this patent
application, and which is incorporated herein by reference.
[0131] In addition to selecting connections, the CCM performs many
other functions in the context of call processing. It not only can
control routing and select the actual connections, but it also can
validate callers, control echo cancellers, generate billing
information, invoke intelligent network functions, access remote
databases, manage traffic, and balance network loads. One skilled
in the art will appreciate how the CCM described below can be
adapted to operate in the above embodiments.
[0132] FIG. 7 depicts a version of the CCM. Other versions also are
contemplated. In the embodiment of FIG. 7, the CCM 702 controls an
ATM interworking unit, such as an ATM interworking multiplexer
(mux) that performs interworking of DS0s and VPI/VCIs. However, the
CCM may control other communications devices and connections in
other embodiments.
[0133] The CCM 702 comprises a signaling platform 704, a control
platform 706, and an application platform 708. Each of the
platforms 704, 706, and 708 is coupled to the other platforms.
[0134] The signaling platform 704 is externally coupled to the
signaling systems--in particular to SS7 signaling systems having a
message transfer part (MTP), an ISDN user part (ISUP), a signaling
connection control part (SCCP), an intelligent network application
part (INAP), and a transaction capabilities application part
(TCAP). The control platform 706 is externally coupled to an
interworking unit control, an echo control, a resource control,
billing, and operations.
[0135] The signaling platform 704 preferably is an SS7 platform
that comprises MTP levels 1-3, ISUP, TCAP, SCCP, and INAP
functionality and is operational to transmit and receive the SS7
messages. The ISUP, SCCP, INAP, and TCAP functionality use MTP to
transmit and receive the SS7 messages. Together, this functionality
is referred as an "SS7 stack," and it is well known. The software
required by one skilled in the art to configure an SS7 stack is
commercially available, for example, from the Trillium company.
[0136] The control platform 706 is comprised of various external
interfaces including an interworking unit interface, an echo
interface, a resource control interface, a billing interface, and
an operations interface. The interworking unit interface exchanges
messages with at least one interworking unit. These messages
comprise DS0 to VPI/VCI assignments, acknowledgments, and status
information. The echo control interface exchanges messages with
echo control systems. Messages exchanged with echo control systems
might include instructions to enable or disable echo cancellation
on particular DS0s, acknowledgments, and status information.
[0137] The resource control interface exchanges messages with
external resources. Examples of such resources are devices that
implement continuity testing, encryption, compression, tone
detection/transmission, voice detection, and voice messaging. The
messages exchanged with resources are instructions to apply the
resource to particular DS0s, acknowledgments, and status
information. For example, a message may instruct a continuity
testing resource to provide a loopback or to send and detect a tone
for a continuity test.
[0138] The billing interface transfers pertinent billing
information to a billing system. Typical billing information
includes the parties to the call, time points for the call, and any
special features applied to the call. The operations interface
allows for the configuration and control of the CCM 702. One
skilled in the art will appreciate how to produce the software for
the interfaces in the control platform 706.
[0139] The application platform 708 is functional to process
signaling information from the signaling platform 704 in order to
select connections. The identity of the selected connections are
provided to the control platform 706 for the interworking unit
interface. The application platform 708 is responsible for
validation, translation, routing, call control, exceptions,
screening, and error handling. In addition to providing the control
requirements for the interworking unit, the application platform
708 also provides requirements for echo control and resource
control to the appropriate interface of the control platform 706.
In addition, the application platform 708 generates signaling
information for transmission by the signaling platform 704. The
signaling information might be ISUP, INAP, or TCAP messages to
external network elements. Pertinent information for each call is
stored in a call control block (CCB) for the call. The CCB can be
used for tracking and billing the call.
[0140] The application platform 708 operates in general accord with
the Basic Call Model (BCM) defined by the ITU. An instance of the
BCM is created to handle each call. The BCM includes an originating
process and a terminating process. The application platform 708
includes a service switching function (SSF) that is used to invoke
the service control function (SCF). Typically, the SCF is contained
in a service control point (SCP). The SCF is queried with TCAP or
INAP messages. The originating or terminating processes will access
remote databases with intelligent network (IN) functionality via
the SSF function.
[0141] Software requirements for the application platform 708 can
be produced in specification and description language (SDL) defined
in ITU-T Z.100. The SDL can be converted into C code. Additional C
and C++ code can be added as required to establish the
environment.
[0142] The CCM 702 can be comprised of the above-described software
loaded onto a computer. The computer can be an Integrated Micro
Products (IMP) FT-Sparc 600 using the Solaris operating system and
conventional database systems. It may be desirable to utilize the
multi-threading capability of a Unix operating system.
[0143] From FIG. 7, it can be seen that the application platform
708 processes signaling information to control numerous systems and
facilitate call connections and services. The SS7 signaling is
exchanged with external components through the signaling platform
704, and control information is exchanged with external systems
through the control platform 706. Advantageously, the CCM 702 is
not integrated into a switch central processing unit (CPU) that is
coupled to a switching matrix. Unlike an SCP, the CCM 702 is
capable of processing ISUP messages independently of TCAP
queries.
[0144] SS7 Message Designations
[0145] SS7 messages are well known. Designations for various SS7
messages commonly are used. Those skilled in the art are familiar
with the following message designations:
[0146] ACM--Address Complete Message
[0147] ANM--Answer Message
[0148] BLO--Blocking
[0149] BLA--Blocking Acknowledgment
[0150] CPG--Call Progress
[0151] CRG--Charge Information
[0152] CGB--Circuit Group Blocking
[0153] CGBA--Circuit Group Blocking Acknowledgment
[0154] GRS--Circuit Group Reset
[0155] GRA--Circuit Group Reset Acknowledgment
[0156] CGU--Circuit Group Unblocking
[0157] CGUA--Circuit Group Unblocking Acknowledgment
[0158] CQM--Circuit Group Query
[0159] CQR--Circuit Group Query Response
[0160] CRM--Circuit Reservation Message
[0161] CRA--Circuit Reservation Acknowledgment
[0162] CVT--Circuit Validation Test
[0163] CVR--Circuit Validation Response
[0164] CFN--Confusion
[0165] COT--Continuity
[0166] CCR--Continuity Check Request
[0167] EXM--Exit Message
[0168] INF--Information
[0169] INR--Information Request
[0170] IAM--Initial Address
[0171] LPA--Loop Back Acknowledgment
[0172] PAM--Pass Along
[0173] REL--Release
[0174] RLC--Release Complete
[0175] RSC--Reset Circuit
[0176] RES--Resume
[0177] SUS--Suspend
[0178] UBL--Unblocking
[0179] UBA--Unblocking Acknowledgment
[0180] UCIC--Unequipped Circuit Identification Code.
[0181] CCM Tables
[0182] Call processing typically entails two aspects. First, an
incoming or "originating" connection is recognized by an
originating call process. For example, the initial connection that
a call uses to enter a network is the originating connection in
that network. Second, an outgoing or "terminating" connection is
selected by a terminating call process. For example, the
terminating connection is coupled to the originating connection in
order to extend the call through the network. These two aspects of
call processing are referred to as the originating side of the call
and the terminating side of the call.
[0183] FIG. 8 depicts a data structure used by the application
platform 708 to execute the BCM. This is accomplished through a
series of tables that point to one another in various ways. The
pointers are typically comprised of next function and next index
designations. The next function points to the next table, and the
next index points to an entry or a range of entries in that table.
The data structure has a trunk circuit table 802, a trunk group
table 804, an exception table 806, an ANI table 808, a called
number table 810, and a routing table 812.
[0184] The trunk circuit table 802 contains information related to
the connections. Typically, the connections are DS0 or ATM
connections. Initially, the trunk circuit table 802 is used to
retrieve information about the originating connection. Later, the
table is used to retrieve information about the terminating
connection. When the originating connection is being processed, the
trunk group number in the trunk circuit table 802 points to the
applicable trunk group for the originating connection in the trunk
group table 804.
[0185] The trunk group table 804 contains information related to
the originating and terminating trunk groups. When the originating
connection is being processed, the trunk group table 804 provides
information relevant to the trunk group for the originating
connection and typically points to the exception table 806.
[0186] The exception table 806 is used to identify various
exception conditions related to the call that may influence the
routing or other handling of the call. Typically, the exception
table 806 points to the ANI table 808. Although, the exception
table 806 may point directly to the trunk group table 804, the
called number table 810, or the routing table 812.
[0187] The ANI table 808 is used to identify any special
characteristics related to the caller's number. The caller's number
is commonly known as automatic number identification (ANI). The ANI
table 808 typically points to the called number table 810.
Although, the ANI table 808 may point directly to the trunk group
table 804 or the routing table 812.
[0188] The called number table 810 is used to identify routing
requirements based on the called number. This will be the case for
standard telephone calls. The called number table 810 typically
points to the routing table 812. Although, it may point to the
trunk group table 804.
[0189] The routing table 812 has information relating to the
routing of the call for the various connections. The routing table
812 is entered from a pointer in the exception table 806, the ANI
table 808, or the called number table 810. The routing table 812
typically points to a trunk group in the trunk group table 804.
[0190] When the exception table 806, the ANI table 808, the called
number table 810, or the routing table 812 point to the trunk group
table 804, they effectively select the terminating trunk group.
When the terminating connection is being processed, the trunk group
number in the trunk group table 804 points to the trunk group that
contains the applicable terminating connection in the trunk circuit
table 804.
[0191] The terminating trunk circuit is used to extend the call.
The trunk circuit is typically a VPI/VCI or a DS0. Thus, it can be
seen that by migrating through the tables, a terminating connection
can be selected for a call.
[0192] FIG. 9 is an overlay of FIG. 8. The tables from FIG. 8 are
present, but for clarity, their pointers have been omitted. FIG. 9
illustrates additional tables that can be accessed from the tables
of FIG. 8. These include a CCM ID table 902, a treatment table 904,
a query/response table 906, and a message table 908.
[0193] The CCM ID table 902 contains various CCM SS7 point codes.
It can be accessed from the trunk group table 804, and it points
back to the trunk group table 804.
[0194] The treatment table 904 identifies various special actions
to be taken in the course of call processing. This will typically
result in the transmission of a release message (REL) and a cause
value. The treatment table 904 can be accessed from the trunk
circuit table 802, the trunk group table 804, the exception table
806, the ANI table 808, the called number table 810, the routing
table 812, and the query/response table 906.
[0195] The query/response table 906 has information used to invoke
the SCF. It can be accessed by the trunk group table 804, the
exception table 806, the ANI table 808, the called number table
810, and the routing table 812. It points to the trunk group table
804, the exception table 806, the ANI table 808, the called number
table 810, the routing table 812, and the treatment table 904.
[0196] The message table 908 is used to provide instructions for
messages from the termination side of the call. It can be accessed
by the trunk group table 804 and points to the trunk group table
804.
[0197] FIGS. 10-17 depict examples of the various tables described
above. FIG. 10 depicts an example of the trunk circuit table.
Initially, the trunk circuit table is used to access information
about the originating circuit. Later in the processing, it is used
to provide information about the terminating circuit. For
originating circuit processing, the associated point code is used
to enter the table. This is the point code of the switch or CCM
associated with the originating circuit. For terminating circuit
processing, the trunk group number is used to enter the table.
[0198] The table also contains the circuit identification code
(CIC). The CIC identifies the circuit which is typically a DS0 or a
VPI/VCI. Thus, the invention is capable of mapping the SS7 CICs to
the ATM VPI/VCI. If the circuit is ATM, the virtual path (VP) and
the virtual channel (VC) also can be used for identification. The
group member number is a numeric code that is used for terminating
circuit selection. The hardware identifier identifies the location
of the hardware associated with the originating circuit. The echo
canceller (EC) identification (ID) entry identifies the echo
canceller for the originating circuit.
[0199] The remaining fields are dynamic in that they are filled
during call processing. The echo control entry is filled based on
three fields in signaling messages: the echo suppresser indicator
in the IAM or CRM, the echo control device indicator in the ACM or
CPM, and the information transfer capability in the IAM. This
information is used to determine if echo control is required on the
call. The satellite indicator is filled with the satellite
indicator in the IAM or CRM. It may be used to reject a call if too
many satellites are used. The circuit status indicates if the given
circuit is idle, blocked, or not blocked. The circuit state
indicates the current state of the circuit, for example, active or
transient. The time/date indicates when the idle circuit went
idle.
[0200] FIG. 11 depicts an example of the trunk group table. During
origination processing, the trunk group number from the trunk
circuit table is used to key into the trunk table. Glare resolution
indicates how a glare situation is to be resolved. Glare is dual
seizure of the same circuit. If the glare resolution entry is set
to "even/odd," the network element with the higher point code
controls the even circuits, and the network element with the lower
point code controls the odd circuits. If the glare resolution entry
is set to "all," the CCM controls all of the circuits. If the glare
resolution entry is set to "none," the CCM yields. The continuity
control entry lists the percent of calls requiring continuity tests
on the trunk group.
[0201] The common language location identifier (CLLI) entry is a
Bellcore standardized entry. The satellite trunk group entry
indicates that the trunk group uses a satellite. The satellite
trunk group entry is used in conjunction with the satellite
indicator field described above to determine if the call has used
too many satellite connections and, therefore, must be rejected.
The service indicator indicates if the incoming message is from a
CCM (ATM) or a switch (TDM). The outgoing message index (OMI)
points to the message table so that outgoing messages can obtain
parameters. The associated number plan area (NPA) entry identifies
the area code.
[0202] Selection sequence indicates the methodology that will be
used to select a connection. The selection sequence field
designations tell the trunk group to select circuits based on the
following: least idle, most idle, ascending, descending, clockwise,
and counterclockwise. The hop counter is decremented from the IAM.
If the hop counter is zero, the call is released. Automatic
congestion control (ACC) active indicates whether or not congestion
control is active. If automatic congestion control is active, the
CCM may release the call. During termination processing, the next
function and index are used to enter the trunk circuit table.
[0203] FIG. 12 depicts an example of the exception table. The index
is used as a pointer to enter the table. The carrier selection
identification (ID) parameter indicates how the caller reached the
network and is used for routing certain types of calls. The
following are used for this field: spare or no indication, selected
carrier identification code presubscribed and input by the calling
party, selected carrier identification code presubscribed and not
input by the calling party, selected carrier identification code
presubscribed and no indication of input by the calling party, and
selected carrier identification code not presubscribed and input by
the calling party. The carrier identification (ID) indicates the
network that the caller wants to use. This is used to route calls
directly to the desired network. The called party number nature of
address differentiates between 0+ calls, 1+ calls, test calls, and
international calls. For example, international calls might be
routed to a pre-selected international carrier.
[0204] The called party "digits from" and "digits to" focus further
processing unique to a defined range of called numbers. The "digits
from" field is a decimal number ranging from 1-15 digits. It can be
any length and, if filled with less than 15 digits, is filled with
0s for the remaining digits. The "digits to" field is a decimal
number ranging from 1-15 digits. It can be any length and, if
filled with less than 15 digits, is filled with 9s for the
remaining digits. The next function and next index entries point to
the next table which is typically the ANI table.
[0205] FIG. 13 depicts an example of the ANI table. The index is
used to enter the fields of the table. The calling party category
differentiates among types of calling parties, for example, test
calls, emergency calls, and ordinary calls. The calling
party.backslash.charge number entry nature of address indicates how
the ANI is to be obtained. The following is the table fill that is
used in this field: unknown, unique subscriber numbers, ANI not
available or not provided, unique national number, ANI of the
called party included, ANI of the called party not included, ANI of
the called party includes national number, non-unique subscriber
number, non-unique national number, non-unique international
number, test line test code, and all other parameter values.
[0206] The "digits from" and "digits to" focus further processing
unique to ANI within a given range. The data entry indicates if the
ANI represents a data device that does not need echo control.
Originating line information (OLI) differentiates among ordinary
subscriber, multiparty line, ANI failure, station level rating,
special operator handling, automatic identified outward dialing,
coin or non-coin call using database access, 800.backslash.888
service call, coin, prison/inmate service, intercept (blank,
trouble, and regular), operator handled call, outward wide area
telecommunications service, telecommunications relay service (TRS),
cellular services, private paystation, and access for private
virtual network types of service. The next function and next index
point to the next table which is typically the called number
table.
[0207] FIG. 14 depicts an example of the called number table. The
index is used to enter the table. The called number nature of
address entry indicates the type of dialed number, for example,
national versus international. The "digits from" and "digits to"
entries focus further processing unique to a range of called
numbers. The processing follows the processing logic of the "digits
from" and "digits to" fields in FIG. 12. The next function and next
index point to the next table which is typically the routing
table.
[0208] FIG. 15 depicts an example of the routing table. The index
is used to enter the table. The transit network selection (TNS)
network identification (ID) plan indicates the number of digits to
use for the CIC. The transit network selection "digits from" and
"digits to" fields define the range of numbers to identify an
international carrier. The circuit code indicates the need for an
operator on the call. The next function and next index entries in
the routing table are used to identify a trunk group. The second
and third next function/index entries define alternate routes. The
third next function entry can also point back to another set of
next functions in the routing table in order to expand the number
of alternate route choices. The only other entries allowed are
pointers to the treatment table. If the routing table points to the
trunk group table, then the trunk group table typically points to a
trunk circuit in the trunk circuit table. The yield from the trunk
circuit table is the terminating connection for the call.
[0209] It can be seen from FIGS. 10-15 that the tables can be
configured and relate to one another in such a way that call
processes can enter the trunk circuit table for the originating
connection and can traverse through the tables by keying on
information and using pointers. The yield of the tables is
typically a terminating connection identified by the trunk circuit
table. In some cases, treatment is specified by the treatment table
instead of a connection. If, at any point during the processing, a
trunk group can be selected, processing may proceed directly to the
trunk group table for terminating circuit selection. For example,
it may be desirable to route calls from a particular ANI over a
particular set of trunk groups. In this case, the ANI table would
point directly to the trunk group table, and the trunk group table
would point to the trunk circuit table for a terminating circuit.
The default path through the tables is: trunk circuit, trunk group,
exception, ANI, called number, routing, trunk group, and trunk
circuit.
[0210] FIG. 16 depicts an example of the treatment table. Either
the index or the message received cause number are filled and are
used to enter the table. If the index is filled and used to enter
the table, the general location, coding standard, and cause value
indicator are used to generate an SS7 REL. The message received
cause value entry is the cause value in a received SS7 message. If
the message received cause value is filled and used to enter the
table, then the cause value from that message is used in a REL from
the CCM. The next function and next index point to the next
table.
[0211] FIG. 17 depicts an example of the message table. This table
allows the CCM to alter information in outgoing messages. Message
type is used to enter the table, and it represents the outgoing
standard SS7 message type. The parameter is the pertinent parameter
within the outgoing SS7 message. The indexes point to various
entries in the trunk group table and determine if parameters can be
unchanged, omitted, or modified in the outgoing messages.
[0212] Those skilled in the art will appreciate that variations
from the specific embodiments disclosed above are contemplated by
the invention. The invention should not be restricted to the above
embodiments, but should be measured by the following claims.
* * * * *