U.S. patent number 6,961,335 [Application Number 10/158,586] was granted by the patent office on 2005-11-01 for multi-layer ring architecture for fiber-to-the-home telco carrier network.
This patent grant is currently assigned to Verizon Communications Inc.. Invention is credited to Dale Lee Bartholomew, John M. Carman, David Harold Cave, N. Sharon Embrey, Kyle Vincent Evans, Robert D. Farris, Lin H. Kerns, Raymond Ian Millet, R. Andrew Poole, Faye M. Smith.
United States Patent |
6,961,335 |
Millet , et al. |
November 1, 2005 |
Multi-layer ring architecture for fiber-to-the-home telco carrier
network
Abstract
A communications network, for example forming a local exchange
carrier telephone network, utilizes three layers of fiber optic
rings. The point of demarcation between customer premises media and
network media comprises an intelligent soft network interface
device or "soft NID". First layer rings carry telephone and data
communications between the soft NIDs and remote terminals. Several
remote terminals in an area communicate via one of the next higher
level rings to a host digital terminal. The host digital terminals
communicate with each other via a backbone optical fiber ring, and
a media gateway controller on this ring provides high level service
logic. The remote terminals and preferably the host digital
terminals are service switching points (SSPs), for intelligent
services provided by the network. Local legacy switches connect to
remote terminals, whereas a router on the backbone provides
communications to other networks, including legacy long distance
networks.
Inventors: |
Millet; Raymond Ian (Bowie,
MD), Poole; R. Andrew (Round Hill, VA), Embrey; N.
Sharon (Alexandria, VA), Farris; Robert D. (Sterling,
VA), Cave; David Harold (Fairfax, VA), Carman; John
M. (Alexandria, VA), Smith; Faye M. (Alexandria, VA),
Kerns; Lin H. (Springfield, VA), Evans; Kyle Vincent
(Dallas, TX), Bartholomew; Dale Lee (Vienna, VA) |
Assignee: |
Verizon Communications Inc.
(New York, NY)
|
Family
ID: |
35150826 |
Appl.
No.: |
10/158,586 |
Filed: |
May 31, 2002 |
Current U.S.
Class: |
370/356;
370/406 |
Current CPC
Class: |
H04L
12/42 (20130101) |
Current International
Class: |
H04L
12/66 (20060101); H04L 012/66 () |
Field of
Search: |
;370/352,353,355,356,400,401,404,405,406,410,465,466,469,907,419,463,467
;398/58,59 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Dr. Kamran Sistanizadeh, "Spanning the Enterprise with Gigabit
Ethernet", 2001 Yipes Communications, Inc. .
Dr. Kamran Sistanizadeh, "Managed IP Optical Internetworking: A
Regional IP-over-Fiber Network Service Architecture: Opportunity
and Challenges in Networking Services for Business Customers", 2000
Yipes Communications, Inc. .
Ali Kafel, "Softswitches and Softswitch-Based Architectures", N-2G:
Feb. 14, 2001, Carrier IP World Forum 2001. .
Plexus 9000 "Multiservice Switching System: Carrier-class
multiservice switching system delivers unsurpassed density and cost
savings for TDM voice, VoIP and VoATM services, independent of
access methods". .
Voice and Data Switching Solution Offers Unsurpassed Density and
Reliability: "Intellingent, multiservice switching platform
provides Class 4/5 services with unrivaled reliability and highest
level of density in industry". .
Plexus 9000 "Multiservice Switching System: PSTN. New Public
Network. Voice. Data." .
TDM Tandem Switching Solution: "Telica's softswitch-based, packet
switch addresses immediate tandem capacity challenges and provides
migration to a full end office solution." .
PlexView Billing System: "Telica's billing system delivers non-stop
revenue accounting to protect your bottom line." .
Voice Packet Telephony Solution: "A High Capacity, Fault Tolerant
TDM and VoP Switch, Allows switching of voice calls through the
PSTN, IP and ATM networks." .
Plex View: Element Manager: "Telica's PlexView Element Management
System, An Integrated, Modular Solution for Network
Management"..
|
Primary Examiner: Nguyen; Brian
Attorney, Agent or Firm: McDermott Will & Emery LLP
Claims
What is claimed is:
1. A communications network for providing logically switched
telephone service and broadband data communication service, using
packet transport, comprising: soft network interface devices,
including a soft network interface device located at and serving
each respective one of a plurality of customer premises receiving
service via the communications network, each soft network interface
device comprising: a telephone interface for providing telephone
communications over customer premises media, a data interface for
providing broadband data communications over customer premises
media, and an optical network interface; remote terminals; first
layer optical fiber rings, each first layer optical fiber ring
providing packet transport, between optical network interfaces of a
plurality of the soft network interface devices and a remote
terminal, for the telephone service and the broadband data
communication service; host digital terminals; second layer optical
fiber rings, each second layer optical fiber ring providing packet
transport between a plurality of remote terminals and a host
digital terminal; and a third layer optical fiber ring providing
packet transport between the host digital terminals; and a media
gateway controller coupled to one of the rings for communication
through the network, the media gateway controller being programmed
to receive a query from and provide a responsive control
instruction to at least one of a host digital terminal, a remote
terminal and a soft network interface device to implement at least
some service logic for control of the logically switched telephone
service or the broadband data communication service when service is
provided via the communications network to each customer premises;
wherein one of the remote terminals comprises: optical network
interfaces coupled to a plurality of the first layer rings; an
optical network interface coupled to one of the second layer rings;
a routing means; a high-speed bus coupled to the optical network
interfaces and the routing means; at least one telephone switch
interface, for communications with a legacy telephone switch; and a
low-speed bus coupled to the routing means and to the at least one
telephone switch interface.
2. The communications network as in claim 1, wherein: one of the
soft network interface devices comprises a programmable data
processing system; and the data processing system is programmed to
implement a micro-gateway service control function of the network
during processing of signals flowing between the optical network
interface and the telephone and data communications interfaces of
the at least one soft network interface device.
3. The communications network as in claim 2, wherein: the data
processing system is programmable in response to provisioning data
transmitted thereto via the network; and the data processing system
is programmable in response to user commands transmitted thereto
locally, from a respective customer premises media.
4. The communications network as in claim 1, wherein the routing
means comprises a memory and a programmable control module for
controlling writing data to the memory from the buses and reading
data from the memory for output via the buses.
5. The communications network as in claim 1, wherein the at least
one telephone switch interface comprises: a trunk interface for
communication of telephone traffic between the one remote terminal
and the legacy telephone switch in accord with a legacy telephone
traffic protocol; and a signaling gateway for communication of
signaling information between the one remote terminal and the
legacy telephone switch in accord with a legacy telephone signaling
protocol.
6. The communications network as in claim 1, further comprising a
feature server coupled to one of the rings for communication of
information to and from customers through the network in support of
predetermined telephone service features.
7. The communications network as in claim 1, further comprising at
least one data processing system coupled to one of the rings for
provisioning communication with one or more of the soft network
interface devices or with one or more of the terminals via the
network.
8. The communications network as in claim 1, wherein the optical
network interfaces of the soft network interface devices and the
terminals are adapted to provide packet transport for the logically
switched telephone service and the broadband data communication
service through the network rings using an asynchronous transport
mode (ATM) cell protocol.
9. The communications network as in claim 8, wherein the optical
network interfaces of the soft network interface devices and the
terminals are further adapted to transport ATM cells through one or
more of the network rings using Synchronous Optical NETwork
(SONET).
10. The communications network as in claim 1, wherein the telephone
interface of one of the soft network interface devices comprises a
telephone line card for two-way telephone communications over
twisted-pair wiring within a respective one of the customer
premises.
11. The communications network as in claim 10, wherein the data
interface of the one soft network interface device comprises a
local area network interface card.
12. The communications network as in claim 1, further comprising a
router coupled to the third layer optical fiber ring for providing
communications to and from the network via a wide area packet data
network.
13. The communications network as in claim 1, further comprising a
router coupled to the third layer optical fiber ring for providing
traffic and signaling communications to and from the network via a
wide area legacy telephone network.
14. The communications network as in claim 1, further comprising a
soft network interface device, coupled to one of the first layer
optical fiber rings, adapted for providing network services to
equipment of an Internet Service Provider.
15. The communications network as in claim 1, further comprising a
soft network interface device, coupled to one of the first layer
optical fiber rings, adapted for providing network services to a
private intranet.
16. A communications network for providing logically switched
telephone service and broadband data communication service, using
packet transport, comprising: soft network interface devices at
respective customer premises, each soft network interface device
comprising: a telephone interface for providing telephone
communications over customer premises media, a data interface for
providing broadband data communications over customer premises
media, and an optical network interface; remote terminals; first
layer optical fiber rings, each first layer optical fiber ring
providing packet transport, between optical network interfaces of a
plurality of the soft network interface devices and a remote
terminal, for the telephone service and the broadband data
communication service; host digital terminals; second layer optical
fiber rings, each second layer optical fiber ring providing packet
transport between a plurality of remote terminals and a host
digital terminal; and a third layer optical fiber ring providing
packet transport between the host digital terminals; and a media
gateway controller coupled to one of the rings for communication
through the network, the media gateway controller being programmed
to provide at least some service logic for control of the logically
switched telephone service or the broadband data communication
service, wherein at least one of the host digital terminals is
programmed to: detect trigger events during processing for at least
some communications through the one host digital terminal,
communicate with the media gateway controller to obtain service
control instructions upon detection of the trigger events, and to
control the at least some communications through the one host
digital terminal in response to the service control
instructions.
17. A communications network for providing logically switched
telephone service and broadband data communication service, using
packet transport, comprising: soft network interface devices at
respective customer premises, each soft network interface device
comprising: a telephone interface for providing telephone
communications over customer premises media, a data interface for
providing broadband data communications over customer premises
media, and an optical network interface; remote terminals: first
layer optical fiber rings, each first layer optical fiber ring
providing packet transport, between optical network interfaces of a
plurality of the soft network interface devices and a remote
terminal, for the telephone service and the broadband data
communication service; host digital terminals; second layer optical
fiber rings, each second layer optical fiber ring providing packet
transport between a plurality of remote terminals and a host
digital terminal; and a third layer optical fiber ring providing
packet transport between the host digital terminals; and a media
gateway controller coupled to one of the rings for communication
through the network, the media gateway controller being programmed
to provide at least some service logic for control of the logically
switched telephone service or the broadband data communication
service, wherein: one of the remote terminals comprises a
programmable control module; and the control module is programmed
to: detect trigger events during processing for at least some
communications through the one remote terminal, communicate with
the media gateway controller to obtain service control instructions
upon detection of the trigger events, and to control the at least
some communications through the one remote terminal in response to
the service control instructions.
18. A local communications network for providing logically switched
telephone service and broadband data communication service to and
from customer premises, using packet transport, comprising: soft
network interface devices, including a respective soft network
interface device located at and serving each respective one of the
customer premises receiving service via the communications network,
each respective soft network interface device comprising: a) a
telephone interface for providing telephone communications over
customer premises media; b) a data interface for providing data
communications over customer premises media; c) an optical network
interface; and d) a data processing system programmed to control
the operations of the respective soft network interface device to
function as a micro gateway with respect to communications services
for the respective customer premises through the network; a
plurality of optical fiber rings, each ring being coupled to at
least two of the optical network interfaces of the soft network
interface devices; and a remote terminal, comprising: 1) optical
network interfaces coupled to the optical fiber rings; 2) a
broadband interface for communication via a higher level network
media; 3) a control module for controlling routing through the
remote terminal; and 4) a bus system coupled to the optical network
interfaces, the broadband interface and the control module;
wherein: the remote terminal further comprises at least one
interface to a legacy telephone switch; and the bus system
comprises: i) a high-speed bus coupled to the optical network
interfaces in the remote terminal, the broadband interface, and the
control module; and ii) a low-speed bus coupled to the control
module and to the at least one interface to a legacy telephone
switch.
19. The communications network as in claim 18, wherein the
broadband interface comprises an optical network interface adapted
to communicate via an area-wide fiber optic ring.
20. The communications network as in claim 18, wherein the control
module is programmed at least in part to cause the remote terminal
to act as a service switching point (SSP) with regard to one or
more services through the network.
21. A local communications network for providing logically switched
telephone service and broadband data communication service to and
from customer premises, using packet transport, comprising: soft
network interface devices at customer premises, each respective
soft network interface device serving a respective customer
premises, each respective soft network interface device comprising:
a) a telephone interface for providing telephone communications
over customer premises media; b) a data interface for providing
data communications over customer premises media; c) an optical
network interface; and d) a data processing system programmed to
control the operations of the respective soft network interface
device to function as a micro gateway with respect to
communications services for the respective customer premises
through the network; a plurality of optical fiber rings, each ring
being coupled to at least two of the optical network interfaces of
the soft network interface devices; and a remote terminal,
comprising: 1) optical network interfaces coupled to the optical
fiber rings; 2) a broadband interface for communication via a
higher level network media; 3) a control module for controlling
routing through the remote terminal; and 4) a bus system coupled to
the optical network interfaces, the broadband interface and the
control module, wherein the control module is programmed at least
in part to cause the remote terminal to: detect trigger events
during processing for at least some communications through the
remote terminal, communicate with higher level control logic
through the network to obtain service control instructions upon
detection of the trigger events, and to control the at least some
communications through the remote terminal in response to the
service control instructions.
22. A remote terminal for use in a communications network for
providing logically switched telephone service and broadband data
communication service, the remote terminal comprising: a local
optical/electrical interface, for optical communications via a
fiber ring to and from customer premises; an area-wide
optical/electrical interface for optical communications via a
higher level optical network media at a rate higher than used for
communications via the fiber ring to the customer premises; a
telephone interface for communication via a link to a legacy
telephone switch; a control module for controlling routing between
the interfaces, wherein the control module comprises a central
processing unit and memory storing a program for execution by the
central processing unit; a high-speed bus coupled to the
optical/electrical interfaces and the control module; and a
low-speed bus coupled to the control module and to the telephone
interface, wherein: execution of the program by the central
processing unit causes the control module to control the remote
terminal to perform service switching point functions with regard
to communications relating to at least one network service, and in
accord with the execution of the program, the control module causes
the remote terminal to: detect trigger events during processing for
the communications relating to at least one network service through
the remote terminal, communicate via the area-wide
optical/electrical interface with higher level control logic to
obtain service control instructions upon detection of the trigger
events, and to control the communications relating to at least one
network service through the remote terminal in response to the
service control instructions.
Description
RELATED APPLICATION
This application is related to U.S. application Ser. No. 10/158,583
entitled "SOFT NETWORK INTERFACE DEVICE FOR DIGITAL BROADBAND LOCAL
CARRIER NETWORKS" filed on May 31, 2002, now U.S. Pat. No.
6,898,276 issued May 24, 2005, the disclosure of which is entirely
incorporated herein by reference.
FIELD OF INVENTION
The present subject matter relates to an advanced network
architecture, for a local telephone company or similar carrier,
utilizing multiple layers of optical fiber rings extending to the
subscriber premises and to various elements of such a network
architecture.
BACKGROUND
Increasingly, there is a need for a carrier network architecture
capable of providing a variety of communication services, for
example, ranging from voice grade telephone service to packet
switched data services and broadband digital communications
services. Modern society continues to create exponentially
increasing demands for communication of various forms of
information. Desired services now range from simple text and voice
communications up through broadband communications for video and
multimedia applications.
The existing telephone network has fostered much of this growth.
However, the current architecture of that network, essentially
designed in the 1960s, uses time division multiplex technology
optimized for voice grade telephone services. Although many users
are satisfied with the services of such a network, increasingly
many customers are exploring competing options for obtaining
communication services that involve much higher-rate digital
communications. Consequently, telephone carriers are faced with a
need to migrate the existing services up to a higher capacity
network that will support those services as well as the newer
broadband digital services demanded by sophisticated customers.
These trends are forcing telephone service carriers to migrate to a
fast packet network architecture supporting broadband services.
Existing end office switches simply cannot handle broadband
services and are not readily adaptable to the fast packet
operations. A number of proposals have been suggested to upgrade or
replace the telephone network, to provide the newer types of
services.
For example, U.S. Pat. No. 5,864,415 to Williams et al. discloses a
fiber-to-the-home network architecture. Optical fiber extends from
the central office to an intelligent interface device within the
home. The intelligent interface device provides interconnections to
various analog and digital communication media within the home,
including a telephone line and a data network (10BaseT cable). The
Williams patent also suggests use of a ring architecture, for the
higher-level portions of the network.
U.S. Pat. No. 5,541,917 to Robert D. Farris discloses an advanced
intelligent network type communication system, which provides both
telephone service and broadband service. The disclosed architecture
includes service switching point (SSP) type telephone central
offices, signaling transfer points (STPs) and a central controller
implemented as an integrated service control point (ISCP). At least
some services are provided via SSP type host digital terminals
(HDTs) and/or asynchronous transfer mode (ATM) type SSP switches.
The HDT, for example, communicates via optical fiber to optical
network units (ONUs) at the curb-side, and it communicates with
higher level elements of the network via fiber.
Recent proposals for fiber optic metro area networks, such as that
described in the white paper: Sistanizadeh, "Managed IP Optical
Internetworking, a Regional IP-over-Fiber Network Service
Architecture," .COPYRGT. 2000 Yipes Communications, Inc., suggest a
multi-layered optical fiber ring network. A first level ring
connects Ethernet switches that provide access for customer
equipment to Ethernet switches in the distribution plane. A next
level ring connects a number of the distribution switches, and this
ring connects to a switch at a hub on the national ring
network.
While these proposals for network architecture separately address
some of the needs of the carrier, such as the incumbent local
exchange carrier, from that carrier's perspective, each has certain
shortcomings. For example, many of the more recent proposals, such
as that by Sistanizadeh, have emphasized handling of broadband data
traffic. Although these proposals envision carrying voice (e.g. as
voice over IP traffic), they have not adequately addressed issues
regarding service control, particularly in such a manner as to
enable seamless migration of the wide range of existing telephone
services from the old TDM switch network up to the newly proposed
packet or ATM based network. Consequently, they have not really
addressed issues of serving both newer broadband based applications
as well as legacy telephone applications, which many telephone
customers will continue to demand (and pay for) for many years to
come.
Also several U.S. pre-grant patent publications to Benedyk et al.
(US2001/0055380), Sugiyama et al. (US2001/0024438) and Suzuki
(US2001/0027983) disclose proposals for using media gateways to
interface time division multiplexing (TDM) based telephone
equipment to IP-based wide area data networks. These documents also
teach control of telephone service through the media gateways at
least in part by control functionality provided by one or more
media gateway controllers. These architectures apparently are
intended as a migration or partial upgrade strategy for the
existing telephone carriers. In a somewhat similar vein, Telica (of
Marlboro, Mass.) offers a system for interfacing older telephone
switches to an IP-based backbone network. Telica proposes a network
architecture in which a specialized gateway device interfaces
telephone calls and other communications to and from a packet data
core network. Although the functions may be integrated in a single
device or `box` having both switching fabric and service logic,
they have also suggested the possibility of a more distributed
implementation. These proposals have focused on enhanced transport
in higher levels of the network. Although such an approach
alleviates congestion at the tandem level, that approach does not
address issues relating to broadband service transport through
levels beyond the backbone. The broadband services do not
consistently extend to and through the last mile to the actual
customer premises.
Hence a continuing need exists for a network architecture and
elements thereof that will efficiently provide a combination of
broadband services and telephone services, which will enable a
carrier to continue to support existing telephone services as well
as meet demands for ever greater digital bandwidth for newer
broadband applications out to the network edge. A related need
exists for such a network to seamlessly support telephone
applications, whether for newer customers serviced through the
enhanced broadband elements of the network or for customers
accessing the network through remaining legacy equipment.
SUMMARY
The embodiments address the above noted problems and needs by
providing an enhanced network architecture for carrier service,
which supports broadband and voice-grade telephone applications,
and by providing enhanced components for implementing such a
network architecture.
The network embodiment utilizes three or more layers of fiber optic
rings, one layer of which extends to the customer premises. An
intelligent soft network interface device forms the point of
demarcation between the customer premises media and carrier
network. A neighborhood optical fiber ring connects a number of the
interfaces to a remote terminal. Several remote terminals in an
area in turn communicate via the next higher level ring to a host
digital terminal. To provide logically switched services over a
relatively wide area, such as a LATA, several of the host digital
terminals communicate with each other via a core optical fiber
ring, that serves as the third or highest of the three main tiers
of the network embodiment.
To control telephone services and provide call set-up signaling,
the inventive network will also include a centralized media gateway
controller. As disclosed, the remote terminals and preferably the
host digital terminals serve as service switching points (SSPs),
for at least some intelligent services provided by the network. The
media gateway controller will communicate via data links through
the network. The media gateway controller (MGC) will provide
control information to the various network nodes as appropriate,
for example to the soft network interface devices and to the SSPs.
The links from the SSPs to the MGC may utilize separate resources
but preferably use the same ring or rings that interconnect the
SSPs. Signaling communications between the MGC and the other
network nodes, particularly the SSPs, utilize permanent virtual
circuits through the rings of the network.
An embodiment of the soft network interface device incorporates an
optical/electrical interface for communication via the neighborhood
optical ring and one or more interfaces to the specific
subscriber's customer premises media. The soft network interface
device also includes one or more programmable processors, for
implementing intelligent control of the flow of communications
between the network interface and the interfaces to the customer
premises media. The programmable processor(s) implement a
micro-gateway functionality, which may be programmed or
provisioned, preferably by the carrier for some functions and by
the customer for other service related applications.
An initial embodiment of the soft network interface device utilizes
a single data processing unit or system, programmed in two
logically separate parts, to implement certain carrier-network
intelligence as well as the customer's application intelligence.
However, the concepts of the soft network interface device also may
be implemented as two separate units, where one unit (carrier's
unit) comprises the optical/electrical interface and a carrier-side
data processing system, and the second unit comprises the
interfaces to the specific subscriber's customer premises media and
a customer-side data processing system. In the later embodiment,
the carrier's unit would provide a standard interface, allowing the
customer to purchase and install the second unit having the desired
interfaces and applications processing capacity, essentially as an
off-the-shelf commodity item.
The embodiment of the MGC runs applications to implement the
service control logic of the network, particularly for telephone
like services. Applications running on the MGC may access other
control data resources, for example, a LIBD database, an SCP
service database, etc. The additional database resources may reside
on the MGC or on a separate system coupled to the MGC via an
appropriate data communication channel.
In at least some applications, a remote terminal also provides
traffic and signaling communications to and from a legacy telephone
switch. A disclosed embodiment of a remote terminal for such an
application comprises a local optical/electrical interface, for
optical communications via a fiber ring to and from customer
premises. An area-wide optical/electrical interface, typically for
coupling to the next higher level ring, enables optical
communications via the higher level optical network media, at a
rate which is higher than used for communications via the fiber
rings to the customer premises. This embodiment of the remote
terminal also includes an interface for communication via a link to
a legacy telephone switch. A control module controls routing
between the interfaces within the remote terminal. The embodiment
also includes two different buses in the remote terminal. A
high-speed bus is coupled to the optical network interfaces and the
control module; and a low-speed bus is coupled to the control
module and to the interface for the link to the legacy telephone
switch.
Additional objects, advantages and novel features of the
embodiments will be set forth in part in the description which
follows, and in part will become apparent to those skilled in the
art upon examination of the following and the accompanying drawings
or may be learned by practice of the embodiments. The objects and
advantages of the inventive concepts may be realized and attained
by means of the methodologies, instrumentalities and combinations
particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawing figures depict preferred embodiments by way of example,
not by way of limitations. In the figures, like reference numerals
refer to the same or similar elements.
FIG. 1 is a functional block diagram of an embodiment of a
multi-ring network architecture.
FIG. 2 is a functional block diagram of an exemplary embodiment of
a soft network interface device, for use in the network of FIG.
1.
FIG. 3 is a functional block diagram of an embodiment of a remote
terminal for use in the network of FIG. 1.
FIG. 4 is a functional block diagram of a personal computer or
workstation, which may serve as any one of several of the devices
in the network of FIG. 1.
FIG. 5 is a functional block diagram of a server or host computer,
which may serve as any one of several of the devices in the network
of FIG. 1.
FIG. 6 is a simplified signal flow diagram, useful in explaining
the processing of a simple telephone service call through the
network of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The various embodiments disclosed herein relate to network
architectures and components thereof, for providing carrier grade
services, both as a new transport for existing telephone services
and for a wide range of higher data-rate services. The embodiments
also integrate transport for traffic and signaling to and from
legacy systems, such as legacy telephone switches and/or long
distance networks.
Reference now is made in detail to the presently preferred
embodiments, examples of which are illustrated in the accompanying
drawings and discussed below. FIG. 1 shows a simplified
architecture for a local carrier's network 1, which utilizes three
or more layers of fiber optic rings. The first tier or layer of the
network is the multi-subscriber local fiber optic. A local fiber
optic ring 3 could serve a single customer premises having a high
requirement for bandwidth, for example, a business complex.
However, the typical local fiber optic area ring 3 serves a number
of residential or business customers within a given neighborhood,
and as a result, is sometimes referred to as the "neighborhood
ring." The next level is the area-wide fiber optic ring 5, which
interconnects a number of number of the local rings 5 in a given
area. The area ring 5 also provides communications to and from the
next higher regional layer. In a typical local exchange carrier
network, the regional backbone ring is a local access transit area
(LATA) ring 7.
Several elements of the network are identified using telephone
network terminology, such as remote terminals (RTs), host digital
terminals (HDTs) and service switching points (SSPs). It should be
noted, however, that such elements of the network do not exactly
correspond to similarly named components of existing telephone
networks. Here, these terms refer to certain intelligent nodes of
the advanced network, as will be discussed in more detail
below.
The first ring layer 3 extends between the remote terminals (RTs)
11 and the customer premises 9. The edge devices at the customer
premises 9 are embodied as soft network interface devices or "soft
NIDs" 13. These NIDS 13 are soft in that they incorporate
programmable communications control and protocol translation
capabilities involved in implementation and delivery of network
services. Also, these edge devices implement one or more generic
network terminations, facing toward the customer side, at which
point it is possible to connect-in any one or more of a number of
readily available interface cards or line cards, to provide the
physical layer interface to the media within each particular
customer's premises.
The soft network interface device (soft NID) 13 at each customer
premises 9 terminates the customer premises wiring and provides the
interface to the first level ring 3. As such, each NID 13 includes
one or more interface cards, supporting two-way communication
connections to the media utilized in the particular home or
business premises 9. Typically, a soft NID 13 will provide a
standard telephone line interface for voice telephone services as
well as one or more interfaces for data services on the same or
preferably separate in-house wiring. At least one data service
provides digital broadband communications capabilities.
Hence, in the illustrated example, the soft NID 13 includes a line
card that provides a standard telephone line interface over twisted
wire pair to one or more analog telephones or the like 15. Another
interface card typically provides a local data connection, such as
an Ethernet link over CAT-5 wiring to personal computers or other
data devices 17. Another card could provide a separate video link
directly to television sets 19 or from video cameras or recorders,
using an analog or digital protocol. Alternatively, the
television(s) 19 in a customer premises 9 could use the same
digital link as the PCs 17. The TV 19 may be compatible with a
digital video protocol on the data link, or the subscriber may use
a set-top box (STB) decoder 18 to convert the digital video to a
signal compatible with the particular type of TV set 19.
The soft NID 13 also includes an optical/electrical interface to
the first level fiber optic ring 3. The intelligent processing and
routing element, between the customer premises media interface(s)
and the optical/electrical interface, essentially controls the NID
13 to operate as a micro-gateway (MG) at the edge of the carrier's
network. This gateway functionality essentially provides logical
interfaces as well as two-way protocol conversions between the
in-house communication protocols on the wiring or other media in
the customer premises and the fast packet elements of the network
1. The logical interfaces provided by the MG support the
appropriate service logic, for the services and service features
offered through the network 1. For voice telephone service, for
example, the NID converts between analog and digital formats,
implements the desired voice coding and decoding scheme, packetizes
and depacketizes the encoded voice information, and performs any
necessary address processing. The structure and functionality of an
embodiment of the soft NID 13 is discussed in more detailed below,
with reference to FIG. 2.
A number of the soft NID type edge devices 13 communicate via the
first level optical fiber ring 3 to a remote terminal (RT) 11. Each
remote terminal 11 may serve several first level rings 3 providing
communications to and from customer premises 9, although the simple
example shows only one ring 3 per remote terminal 11.
In the illustrated architecture, the remote terminal 11 functions
as a first level intelligent router or switch. Although referred to
as an SSP, it should be noted that such a node in the network 1 is
not analogous to the TDM based switch typically utilized in the
SSPs of the existing telephone network. The RT 11 instead is a
packet-switch type router. The SSP capability here is a more
generic ability to recognize a trigger, i.e., a need for
information or an instruction regarding how to process a customer
communication, and communicate with a higher level node having
service logic, to obtain the necessary information or instruction.
Hence the intelligence of this network routing node 11 includes the
added functionality to recognize events and obtain instructions or
necessary information from higher level control logic, such that
the remote terminal 11 functions as a packet-switch with service
switching point (SSP) capabilities.
In the network 1, the RTs 11 are relatively high-capacity devices
providing packet-based routing and switching to implement desired
voice and data services. However, for at least the telephone type
services and preferably for some broad band services, the SSP
capable RTs 11 are the points at which much of the actual control
of the services is implemented. Such an SSP capable RT may
implement some service logic based on its own internal
provisioning, but for other services or features the SSP performs
the service control in response to instructions from a higher level
controller, as discussed more later.
At lease one of the remote terminals (RTs) 11 on a given area ring
5 also provides an interface for connection to legacy telephone
type end office (EO) switching systems 21 in the carrier's region
of operation. The EO switch 21 provides plain old telephone service
(POTS) to analog subscribers and/or ISDN subscribers, shown having
telephones 15', as in the existing telephone network. However, the
interoffice communications to and from that switch 21 utilize
capacity within the fast packet portions of the enhanced network
1.
The links from an RT 11 to an EO switch 21 include standard digital
telephone trunk circuits (shown as a solid line) over wire or
optical media or the like, and preferably include out-of-band
signaling links (shown as a dotted line), for example, a signaling
system 7 (SS7) link. From the perspective of the EO switch 21, the
RT 11 appears like both another switch (tandem or end office) of
the old telephone network and as a signaling transfer point (STP)
of the old interoffice signaling network. The RT 11 serves as a
media gateway for the legacy traffic to the fast packet portion of
the network 1, and the RT 11 interworks and routes the associated
signaling traffic.
Several remote terminals 11 in an area in turn communicate via the
next higher level ring 5 to a host digital terminal (HDT). For most
services, the remote terminals (RTs) 11 perform the service
switching point (SSP) functions as outlined above. However, for
some types of services, the HDTs 23 also perform SSP functions
similar to those implemented by the RTs 11. Like an RT 11, the HDT
23 is a relatively high-capacity router and service switch, which
provides packet-based routing and switching to implement desired
voice and data services. The logic for HDT handling of most of the
services may reside in the HDT 23, or for some services, the SSP
functionality may perform the control in response to instructions
from a higher level controller, as discussed more later.
To provide logically switched services over a relatively wide area,
such as a local access transport area or "LATA," several of the
HDTs 23 communicate with each other via the third level optical
fiber ring 7. Each of the HDTs 23 will typically communicate
through two or more of the intermediate level rings 5 with remote
terminals 11, and thus to equipment at a large number of customer
locations 9 within the overall service area. Of course, the
geographic area encompassed by the network 1 may include any
desired physical area serviced by the particular carrier, depending
on its business structure and the like. The LATA area may be
convenient for local exchange carriers, if the regulatory agencies
maintain the current scheme of LATA boundaries for determining when
traffic is long distance traffic and must be handed off to an
interexchange carrier.
Legacy switches, such as the EO switch 21, may connect into an HDT
23, but typically connect to an RT 11, as discussed above. The
structure of the HDT 23 is generally similar to that of the RT 11,
except that the switch/router hardware within the HDT is designed
for a higher traffic capacity, to support the communications around
the backbone ring 7.
The backbone ring 7 also connects to one or more routers 25 that
provide communications between the network 1 and other networks.
The router 25, for example, routes both customer traffic and
signaling to and from optical fiber ring systems 27 in other
regions. The same router 25 (or another router) on the backbone
ring 7 provides an interface to other telephone networks 29
utilizing legacy technologies, for example, to the point of
presence (POP) of a telephone interexchange carrier's network. The
interface to telephone-type legacy networks typically will include
a time division multiplexed (TDM) digital link for voice traffic,
for example via Synchronous Optical NETwork (SONET) or wired IMT
trunk circuits. This interface typically will also include an SS7
signaling link, for network signaling communications with the
legacy network(s) 29. Hence, the router 29 will include the
appropriate interfaces to the legacy links and will provide the
appropriate protocol conversions between the legacy protocols and
those used by the fast packet elements of the network 1.
To support many of the familiar telephone services as well as some
services to be developed in future, the network 1 further includes
one or more feature servers 31, one of which appears in the
simplified illustration in FIG. 1. In the embodiment, an HDT 23 on
the backbone ring 7 connects to the feature server 31, although it
is envisaged that the feature server could connect to a local ring
3 through a soft NID 13 or directly to a remote terminal 11. In its
simplest form, the feature server provides specialized voice
telephone service related processing. For example, the feature
server 31 may provide voice recording, speech/voice recognition
and/or voice response capabilities and/or conversions between
speech and text.
To control telephone services and provide call set-up signaling,
the inventive network will also include a centralized media gateway
controller. The media gateway controller or "MGC" 33 connects via
logical data links through the network 1 to the various SSPs. The
MGC 33 responds to queries and provides control information to the
various remote terminals (RTs) 11 and/or the HDTs 23, when those
nodes function as SSPs during processing of a voice telephone call
or other network service. For some service applications, the MGC 33
may also provide control information to the micro-gateways
implemented in the soft NIDs 13. The links from the SSPs to the MGC
may utilize separate resources, but preferably these logical links
use the same rings that interconnects the SSPs. Signaling
communications between the MGC and the other network nodes 11 and
21 that serve as SSPs preferably utilize permanent virtual circuits
through the rings of the network. Any virtual circuits used to
provide communications between the MGC 33 and the soft NIDs 13 are
"switched," in that they are set-up through the network as needed
and torn down when the signaling is complete.
Physically, the MGC 33 is a general purpose computer system with an
appropriate communications interface to the network 1. The MGC 33
runs one or more applications to implement the service control
logic of the network, particularly for telephone like services.
Applications running on the MGC may access other control data
resources, for example, a LIBD database, an SCP service database,
etc. The additional database resources may reside on the MGC 33 or
on a separate system (not shown) coupled to the MGC 33 via an
appropriate data communication channel. In practice, the MGC 33 may
be implemented as a redundant pair of systems, both of which run
the same service logic software and store the same subscriber
specific service control data.
The illustrated network 1 supports telephone services between
stations 15 or between a station 15 and a station 15'. The network
also supports telephone service for stations 15, 15' to or from
long distance carrier networks, whether the other carriers use
similar fiber networks 27 or legacy networks 29.
The network 1 also supports a broad range of packet data services,
many of which entail broadband communications. The most common
examples of data services, particularly as might utilize broadband
capabilities of the network 1, include Internet services and
private data network services. A typical Internet access service
involves a packet data session for a PC 17 or the like extending
through the network 1 from the customer's soft NID 13 to a network
41 of an Internet Service Provider ISP. The ISP network may connect
to the network 1 at any convenient point. To the local carrier
operating network 1, the ISP is simply another customer, in this
case, one requiring broadband data service. In the illustrated
embodiment, the ISP type customer has a soft NID 13 on a local ring
3. To the network 1, the soft NID 13 of the ISP appears like other
soft NIDs, except that the service provisioning associated
therewith relates specifically to the data traffic and loading
which the ISP requires. The ISP's soft NID 13 may be similar to
other soft NIDs, but typically, this soft NID is a router of a
particular size so as to enable throughput to the ISP network 41
matching the projected traffic load for the ISPs access services
and likely need not include any interface for telephone equipment
at the customer premises.
In a similar manner, an Intranet 43 for private network services is
essentially another data transport customer of the network 1. Like
the ISP network 41, the Intranet connects to a ring 3 through a
router type implementation of the soft NID 13. Alternatively, the
Intranet 43 could connect to the network 1 directly through an RT
11 or an HDT 23 or even the router 25, but preferably the Intranet
4 connects to the network 1 via a soft NID 13, like any other
customer.
Communications on the rings 3, 5 and 7 utilize packet protocols,
such as Internet Protocol (IP) and Transmission Control Protocol
(TCP). At least in initial embodiments, the physical transport
layer will utilize aynchronous transfer mode (ATM) cells
transmitted over the optical waves utilized by the actual fibers.
The fiber transport of the ATM cells could utilize SONET or other
fiber ring protocols.
The International Standards Organization (ISO) Open Systems
Interconnection (OSI) reference model specifies a hierarchy of
protocol layers and defines the function of each layer in the
network. The lowest layer defined by the OSI model is the physical
layer (L1). This layer provides transmission of raw data bits over
the physical communication channel through the particular network.
The layer next to the physical layer is the data link layer (L2).
The data link layer transforms the physical layer, which interfaces
directly with the channel medium, into a communication link that
appears error-free to the next layer above, known as the network
layer (L3). The data link layer performs such functions as
structuring data into packets or frames, and attaching control
information to the packets or frames, such as checksums for error
detection, and packet numbers. The network layer provides
capabilities required to control connections between end systems
through the network, e.g. set-up and tear-down of connections.
An embodiment of the network 1 could utilize SONET and ATM as the
L1/L2 protocols. The neighborhood rings 3 might operate at lower
SONET rates, e.g. OC-1 or OC-3, whereas the rings 5 and 7 would
operate at higher-rate levels of the protocol. Preferably, the
network 1 utilizes Internet Protocol, for example, as the L3
network layer protocol.
In the OSI model, a transport layer protocol (L4) runs above the
network layer. The transport layer provides control of data
transfer between end systems. Above the transport layer, a session
layer (L5) is responsible for establishing and managing
communication between presentation entities. For example, the
session layer determines which entity communicates at a given time
and establishes any necessary synchronization between the entities.
For at least some applications, the network 1 will often utilize
TCP as part of the L4/L5 layers of the protocol stack.
Above the session layer, a presentation layer (L6) serves to
represent information transferred between applications in a manner
that preserves its meaning (semantics) while resolving differences
in the actual representation (syntax). A protocol (L7) that is
specific to the actual application that utilizes the information
communicated runs at the top of the protocol stack.
In a network utilizing such a protocol stack, virtual circuits can
be defined utilizing the ATM cell header information, such as the
virtual path identifier (VPI) and the virtual circuit identifier
(VCI). Sessions, for data or voice can utilize end-to-end
addressing, based on the IP frame addressing data. The TCP port
identification, which points to the user application, also can be
utilized to distinguish service type and/or destination.
FIG. 2 shows the elements of an exemplary embodiment of a soft
network interface device or "soft NID" 13, in block diagram form.
This particular implementation is one intended to support a
combination of different telephone and data services available via
the network. As discussed more below, the example is one
appropriate for a residence or small/home business customer,
although those skilled in the art will recognize how to scale the
concept to service larger volume customers requiring services to
more telephone stations and/or higher digital bandwidth for data
communication applications.
As noted earlier, the soft network interface device (soft NID) 13
at each customer premises terminates the customer premises wiring
and provides the interface to the first level ring 3. To that end,
each NID 13 includes one or more interface cards, supporting
two-way communication connections to the media 51 utilized in the
particular home or business premises.
In the multi-service embodiment of FIG. 2, the soft NID 13 provides
a standard telephone line interface for voice telephone services as
well as one or more interfaces for data services on the same or
preferably separate in-house wiring. Hence, the illustrated soft
NID 13 includes a telephone line card 53 that provides a standard
telephone line interface over twisted wire pair 55, to one or more
telephones 15 as shown in the earlier drawing. The soft NID 13 also
includes a data interface card, which in the example is an Ethernet
line card 57, for providing two-way Ethernet local area network
(LAN) type communications over CAT-5 cable 59 (shown as multiple
twisted pairs). The soft NID 13 may include other types of line
cards 61, for example, for providing video services over an in-home
coaxial cable 63. The customer may have any number of different
types and combinations of wired or wireless telephone and broadband
communications media within the customer premises, and the customer
would select the appropriate set of line cards to interface to
those media 51 for the desired service applications.
The soft NID 13 also includes an optical/electrical (O/E) interface
65 to the first level fiber optic ring 3. An internal bus network
67 interconnects the customer premises-side interface cards 53, 57
and 61 and the O/E interface 65, and the bus 67 connects all of
those interfaces to elements of an internal data processing system
69. The interface 65 conforms to the physical layer protocols
required by the neighborhood optical ring 3. On the internal side,
however, the O/E interface 65 conforms to the electrical signaling
protocols utilized on the bus network 67 and by the other elements
of the soft NID 13.
The optical rings in the network 1 provide fast packet transport
for all communications through the ring, for example, including the
voice telephone service and all broadband services. The packet
functions may be performed in the O/E interface 65 or in the line
cards.
As noted, the illustrated soft NID 13 includes a telephone line
card 53 that provides a standard telephone line interface over
twisted wire pair 55, to one or more telephones as shown in the
earlier drawing. The line card may provide ISDN type digital
service. The media for the telephones could utilize wireless links,
power lines, or other in-home media. However, for many customers,
the line card 53 provides analog-type plain old telephone service
over the twisted pair wiring 53 to existing standard telephone
equipment, as illustrated in the drawings.
For an analog type plain old telephone service (POTS), the line
card 53 provides two-way conversion between analog and digital
signals. The POTS line card 53 also provides normal telephone line
functions, such as battery feed, over-voltage protection, ringing,
signaling, coding, hybrid and testing (commonly collectively
identified as the `BORSCHT` functions, in the telephone
industry).
The hybrid functionality of the telephone line card 53 performs a
two wire to four wire type conversion. The line card 53 sends and
receives analog signals over a twisted wire pair 55, and the
telephone line card 53 sends and receives digital signals through
the bus 67 and the network rings. More specifically, in the
upstream direction, the telephone line card 53 receives analog
signals from the associated twisted wire pair 55. The line card 53
converts those signals into digital signals in a format compatible
with the bus network 67 and the fast packet communications utilized
by the network 1. The telephone line card 53 supplies the digitized
audio information signals through the bus 67 to the O/E interface
65, for upstream transmission through the fiber ring 3 to the RT 11
serving the particular ring. In the downstream direction, the O/E
interface 65 supplies voice telephone information received from the
ring 3 over the bus network 67 to the telephone line card 53. The
line card 53 in turn converts the downstream digitized information
signals to analog form and couples the resultant analog signals to
the twisted wire pair for two-wire transport to the customer
premise equipment.
An ISDN implementation of the line card 53 would perform functions
similar to those described above for the analog version of the
telephone line card 53, except that the signals provided on the
relevant customer wiring 55 would conform to ISDN standards. In the
example, the telephone line card 53 provided a single telephone
interface to one customer premises line 55. This may be typical for
residential installations. However, high-end residential users and
businesses will require increasing numbers of telephone lines. It
is envisaged that different versions of a telephone line card 53
may support 1, 2, 14, 12, 24 or 32 customer premises telephone
lines in either POTS analog form or digital ISDN form. For business
applications requiring still more lines, the soft NID 13 would
include multiple telephone line cards 53 to provide an aggregate
telephone line capacity to meet the needs of the particular
business customer.
In the preferred embodiments, a second interface card provides a
local data connection. The subscriber may choose any conveniently
available data interface, such as Home Phoneline Networking
Association (HomePNA), IEEE 802.11 wireless LAN, or other home
networking protocols and media. In the illustrated embodiment, the
data interface is an Ethernet line card 57 for data communication
over CAT-5 wiring 59. For a typical residential application, the
Ethernet card 57 would provide 10baseT data communication within
the customer premises. However, other users, particularly business
users, may opt for 100baseT or even gigabit Ethernet type local
area network operations. The line card 57, the bus 67 and the O/E
interface 65 essentially provide two-way interworking between the
data protocols on the customer premises wiring 59 and the
neighborhood fiber ring 3. To the in-home network, the soft-NID 13
appears as another device on the LAN, albeit providing access to
the broader area services available via the network 1.
As noted above, the soft NID 13 may include one or more additional
line cards 61, to support other types of communications within the
premises 9 and provide interfacing thereof to the network 1 via the
ring 3. The additional line cards are selectable at the option of
the owner of the particular customer premises. Examples include
X10, which is a communications protocol for remote control of
electrical devices and communications over standard household AC
power-line wiring, and IEEE 1394, which is a serial interface for
short-range, low-data-rate, infrared communications between
entertainment and computer devices. In the example shown, the soft
NID 13 includes a line card 61 for video communications over
coaxial wiring 63. The video line card 61 may provide analog or
digital programming to television equipment for recording and/or
presentation to a user. Alternatively, the line card may accept
analog or digital video communication for upstream transmission
through the soft NID 13 and the network 1.
The soft NID 13 is an intelligent processing and routing device. To
implement the control logic for these functions, the NID 13
includes a data processing system 69 coupled to the bus 67. The
exemplary data processing system 69 comprises elements of a general
purpose computer programmed to control the interfaces and
communications over the bus 67 in such a manner that the NID 13
operates as a micro-gateway at the edge of the carrier's network
1.
In the embodiment, the data processing system 69 contains a central
processing unit (CPU) 71 and memories 73 connected to the bus 67.
The CPU 71 may contain a single microprocessor, or may contain a
plurality of microprocessors for configuring the data processing
system 69 as a multi-processor system. The memories 73 serve as the
main memory and program storage for the CPU 71. The memories 73
typically include dynamic random access memory (DRAM), a read only
memory (ROM) and high-speed cache memory. The memories 73 may
include other types of devices, such as an electrically erasable
programmable read only memory (EEPROM), flash memory and the like.
Optionally, the data processing system may include a hard disk
drive 75 or other mass storage device, such as a CD or DVD drive, a
floppy disk drive, tape drive, etc.
In operation, the main memories 73 and/or the hard disk 75 store at
least portions of instructions and data for execution by the CPU 71
as well as associated working data. The instructions and data
include various address tables and other routing data needed to
interwork the in-home communications to the transport protocols
utilized in the network 1 as well as some service provisioning
data. The stored information may also include instructions and data
relating to applications and services controlled by the user.
The data processing system 69 is programmable in response to
digital communications received via the ring 3, for example from
the database 39 or from a terminal such as the MOC 37. Typically,
one (or more) of these carrier systems downloads service
provisioning data to the soft NID 13, to enable the NID to provide
specific network services and related features, which the customer
purchases from the carrier. Such data also may be downloaded from
other carriers or service providers, such as a long distance
carrier or an ISP. The data processing system 69 also is
programmable in response to communications received via the
customer premises media 51 and the bus 67, for example from a
telephone 15 and/or a computer 17 in the customer premises 9 (see
FIG. 1). Initial and/or diagnostic programming may be performed via
a local port or removable storage media drive (not shown), such as
a drive for a floppy disk, a compact disc read only memory
(CD-ROM), or an integrated circuit non-volatile memory adapter
(i.e. PC-MCIA adapter).
The data processing system 69 also learns as it provides
communications through the network 1. For example, if the user
calls a particular destination for voice or data communications,
and the network downloads information needed to establish the
session link through the network, the data processing system 69
stores the information for future use, for example, in case the
user calls the same destination again.
As noted, the soft NID 13 essentially is the edge of the carrier's
network. The device connects to the network 1 via the neighborhood
ring 3 and provides the interfaces to the media 51 within the
customer premises. Some micro-gateway functions of the soft NID 13
are programmable by the carrier, typically via data communications
carried through the network and some of the service control logic
of that gateway function is responsive to instructions from other
nodes of the network 1. The micro-gateway functionality, however,
is responsive to user input, for example, to initiate a call or
selected session through the network 1. Also, some functions of the
soft NID 13 are programmable by the user. Hence, the line of
demarcation between the network 1 and customer premises may be
viewed as bisecting the soft NID 13. Logically, the soft NID 13 may
be thought of as partially a customer's device, that is to say as
customer premises equipment (CPE), and partially a network device.
Stated another way, the customer-side interfaces 53, 57 and 63 and
a portion of the logic implemented by the data processing unit 69
are part of the customer premises equipment. However, the O/E
interface 65 and a portion of the logic implemented by the data
processing unit 69 are part of the neighborhood ring 3 on the
carrier's network 1.
It may be helpful to briefly consider two examples relating to the
programmability of the soft NID 13 in somewhat more detail. For
local telephone services, the carrier may download provisioning
data and/or programming to support certain features, such as
three-way calling, into the soft-NID 13. In preferred embodiments,
this programming information comes through the network 1, for
example, from one or more of the carrier's systems in the
operations center 35.
For long distance telephone service, however, the local carrier
treats the communications as a simple pass-through. For the long
distance service, the soft NID 13 only needs the routing or
addressing data to reach the point of presence (POP) of the long
distance carrier of choice, for example, into one of the legacy
networks 29. When the soft NID 13 detects a 1+dialing pattern on
the telephone line, the NID uses the POP addressing data to
initiate a link through the network 1 to the POP of the long
distance carrier. Although the local carrier may download this data
in the same manner as for local call provisioning and service
features, preferably the addressing data to reach the POP is
provided through the network 1, by the long distance carrier, for
example, in response to an on-line subscription to services of that
carrier. Alternatively, such data could be programmed into the soft
NID 13 from a data device, such as a PC 17, at the customer
premises 9.
To support the various programming options, the data processing
unit implements certain access restrictions using appropriate
levels of security protocols. For example, only the carrier's
systems may program basic service provisioning data into the soft
NID 13. Other features, such as speed dial lists are programmable
by the user, and other service data like the PIC code and/or POP
address, is programmable by the user or a recognized third party
(e.g., the long distance carrier of choice.)
The embodiment of FIG. 2 is of course a representative example
only. Those skilled in the art will recognize that the soft NID 13
may take other physical forms. For example, for high traffic
applications, the soft NID 13 may take the form of a router or
packet switch. As another alternative, the concepts of the soft
network interface device may be implemented as two separate units,
where one unit (carrier's unit) comprises the optical/electrical
interface 65 and a carrier-side data processing system. In this
type of embodiment, the second part of the soft NID comprises the
interfaces 53, 57 and 61 to the specific subscriber's customer
premises media 51 and a customer-side data processing system. The
carrier's unit would provide a standard interface, allowing the
customer to purchase and install a version of the second unit
having the desired interfaces and applications processing capacity,
essentially as an off-the-shelf commodity item.
As outlined above, communications on the ring 3 utilize fast packet
technologies, for example TCP/IP on top of appropriate transport
layers, such as ATM and SONET. The optical ring 3 may utilize other
transport protocols, for example Ethernet over fiber as outlined by
Sistanizadeh. In a multi-layer ring network 1, communications
between some customers remain within the area of ring 3. Initial
set-up of such a call or data session may entail control through
the remote terminal 11 and higher network elements to provide the
necessary address data to the soft NIDs 13 serving the particular
customers. However, once the necessary address data is provided to
the soft NIDs 13 (and cached therein for at least some services),
the soft NIDs 13 simply transmit the packets around the ring to
each other. Specifically, the NID 13 sending a packet inserts the
destination address, and the NID 13 intended as the recipient
recognizes that address in the packet as the packet flows around
the ring 3 and captures the packet for further processing at the
destination premises 9.
The coding and decoding (CODEC) equipment in the soft NIDs 13,
typically in the telephone line cards 53, can implement one or more
standard audio encoding schemes. Preferably, the algorithm and its
coding parameters are selectable in response to
instructions/commands exchanged via the network, to enable the line
cards 53 to encode audio information in different formats, and in
particular, at different rates. For example, for a telephone call
going to or from a legacy long distance network 29 or a legacy end
office switch 21, the line card 53 can selectively process audio
information into and out of the standard 56 kb/s PCM utilized by
such legacy systems, although the soft NID 13 and the rings
transport that information between the customer premises 9 and the
node coupled to legacy equipment 21 or 29 in fast packet form.
Alternatively, the encoding for communication of the audio
information through the rings may utilize a lower rate encoding, in
which case the RT 11 or router 25 coupled to the legacy equipment
would transcode the audio data to and from the format used by the
legacy equipment.
For a voice-grade telephone communication between customers using
soft NIDs 13, the CODECs perform compression of the digitized audio
information, and the carrier may control the encoding rate, for
example, in response to network loading. In this manner, the
carrier can effectively throttle down voice traffic by reducing the
data rates of calls through congested portions of the network 1.
The carrier may implement the rate control on a per call basis, by
providing instructions at the start of each call; or the carrier
may control the rate dynamically during each call by providing
instructions to the soft NIDs 13 from time to time as changes if
any are needed. The compression and rate control for the telephone
services reduces the loading each call places on the network 1.
The lower layer protocols (typically layers 1 to 4 or 5) on the
rings are the same on all of the rings, except that each higher
level ring typically carries more traffic and therefore operates at
a higher rate. The rings 3 will typically operate at the same rate,
although one or more of those rings may operate at a higher rate if
the traffic in the neighborhood warrants the higher rate.
Similarly, the rings 5 will typically operate at the same rate,
which is higher than the rate(s) on the rings 3. Again, one or more
of the rings 5 may operate at a higher rate than other similar
level rings 5, if the traffic in a particular area warrants the
higher rate. The backbone ring 7 aggregates traffic from a number
of the rings 5 and operates at the highest rate.
The remote terminals 13 and the host digital terminals 23 may be
implemented by routers having the appropriate throughput capacities
and the appropriate interfaces for the rings 3, 5 and 7. Otherwise,
the remote terminals 13 and the host digital terminals 23 are
generally similar, with one exception. In the illustrated network
embodiment, one or more of the remote terminals 11 includes
additional interfacing elements to provide voice grade traffic and
associated interoffice signaling communications to and from one or
more legacy end office switches 21.
Existing routers with appropriate interfaces may be used and
programmed to serve as the remote terminals (RTs) 11 and the host
digital terminals (HDTs) 23. The inventors propose an advantageous
implementation, particularly for use as a remote terminal 11 that
services a legacy switch 21, and that implementation will be
described with reference to FIG. 3.
The remote terminal (RT) 11 shown in FIG. 3 is an intelligent
packet router specifically adapted to interface between different
layers 3 and 5 of the rings as well as to provide interworking
communication to and from one or more legacy end office switches
21. As discussed more below, the RT 11 in this embodiment includes
the appropriate optical/electrical interfaces, interfaces to trunk
and signaling circuits to/from the legacy switch(es) 21 and two
different internal bus systems. A high speed bus carries the
high-speed packet data to and from the various optical electrical
interfaces. The second bus is a low-speed bus for transport of
telephone service related data (e.g. voice and signaling) at speeds
to/from the interfaces and gateways that convert to and from the
legacy formats compatible with the switch(es) 21.
Hence, the illustrated remote terminal (RT) 11 includes one or more
optical/electrical (O/E) interfaces 111 to one or more of the first
level fiber optic rings 3. On the fiber side, these interfaces
process optical signals at the speeds and in the protocols used on
the first level fiber optic rings 3. The interfaces 111 provide
two-way conversions of the signal speeds and formats on the ring 3
to/from the electrical signal format and speeds used on the high
speed internal bus network 113. The RT 11 also includes another
optical/electrical (O/E) interface 115 coupled to the high speed
internal bus network 113. The O/E interface 115 provides two-way
conversions of the electrical signal format and speeds used on the
high speed internal bus network 113 to/from optical signals at the
speeds and in the protocols used on the second level fiber optic
ring 5. The interface 115 is generally similar to the interfaces
111 except that the interface 115 is adapted to the higher rate
form of the optical signals and protocols used on the ring 5.
The exemplary RT 11 also includes two types of interfaces 117 and
119 specifically adapted for communications with one or more legacy
switches 21. As shown, the RT 11 includes one or more TDM type
trunk interfaces, for example, for connection to electrical or
optical inter-machine trunk (IMT) circuits for transporting
telephone call type traffic to and from a legacy switch 21.
Signaling could use in-band communications. However, it is
preferred that RT 11 also includes one or more SS7 signaling
gateways 119. The signaling gateways 119 convert between the SS7
signaling protocol used by legacy switches 21 and the fast packet
protocols used on the internal buses and on the rings of the
network. To provide sufficient traffic capacity, the RT 11 will
typically include interfaces 117 to a number of the trunk circuits
and gateways 119 to a number of the signaling links for each of the
legacy switches served via the particular RT 11. Within the RT 11,
the interfaces 117 and the gateways 119 connect to the low-speed
bus 121. Of course, it is possible to combine the functions of a
number of the trunk interfaces 117 into one multi-port unit, to
combine a number of the signaling gateways 119, or to provide a
single unit performing both the interface and gateway
functions.
The RT 11 includes a programmable, processor-based control module
123 and a main memory 125 for use in execution of the routing
functions. The high-speed bus network 113 interconnects the O/E
interfaces 111 and 115, and the bus 113 connects all of those
interfaces to elements of the control module 123 and the main
routing memory 125. The low-speed bus network 121 interconnects the
trunk interfaces 117 and the signaling gateways 119 to the elements
of the control module 123 and the main routing memory 125.
For discussion purposes, the routing memory 125 is shown as a
single distinct storage element of the RT 11. Those skilled in the
art will recognize that the functions of this memory may be
implemented in a variety of other ways as well. For example, a
portion of the main memory of the control module 123 may serve as
the routing memory 125. As another option, the memory 125 may
comprise a number of individual memories built into the various
interfaces, although there may still be a small separate part
and/or a part of the memory 125 in the control module 123. In this
later case, the distributed memory elements together perform the
functions of the routing memory 125.
The RT 11 is an intelligent switching and routing device. The
intelligence to implement the control logic of the RT 11 resides in
the programmable control module 123. The exemplary data processing
system that serves as the control module 123 comprises elements of
a general purpose computer programmed to control the interfaces and
communications over the buses 113, 121 in such a manner that the RT
11 performs the routing between the rings and the routing to
and/from the traffic and signaling links for the legacy
switch(es).
In the embodiment, the control module 125 contains a central
processing unit (CPU) 131 and memories 133 connected to the buses
113 and 121. The CPU 131 may contain a single microprocessor, or
may contain a plurality of microprocessors for configuring the
control module 123 as a multi-processor system. The memories 133
serve as the working memory and program storage for the CPU 131.
The memories 133 typically include dynamic random access memory
(DRAM), a read only memory (ROM) and high-speed cache memory. The
memories 133 may include other types of devices, such as an
electrically erasable programmable read only memory (EEPROM), flash
memory and the like and/or one or more hard disk drives or other
mass storage device (not shown). Some implementations will include
back-ups for the control module 123 and possibly for the routing
memory 125.
In operation, the main memories 133 store at least portions of
instructions and data for execution by the CPU 131 as well as
associated working data. The instructions and data include various
address tables and other routing data needed to control the routing
and signaling functions of the RT 11, as well as service
provisioning data related to individual customer services and
service features. The stored information typically is downloaded
from a system of the network carrier through channels through the
network 1, for example from the MOC 37 or the database 39 in the
operations center 35.
For most simple routing functions, for example, upstream from one
O/E interface 111 to another O/E interface 115, the control module
123 controls write-in and read-out operations to and from the main
routing memory 125. For an incoming packet, for example, a
receiving interface such as 111 transmits the packet through the
high speed bus 113 to the memory 125 where it is written into a
designated location. Based on the header information, the control
module 123 identifies the appropriate output port, that is to say
via the O/E interface 115 in our example, and notifies that unit to
read the packet from the memory 125 via the high speed bus 113.
Upon receiving the packet from the memory 125, the O/E interface
115 sends the packet over the ring 5 coupled to that interface.
Similar operations route packets going downstream from interface
115 to one or more of the interfaces 111 and route packets between
interfaces 111.
Packets written to the memory 125 via one bus 113 or 121 may be
output via the other bus 121 or 113, in order to route
communications between the high-speed elements and the elements of
the RT 11 on the low-speed bus 121. For example, to communicate
audio telephone information coming from a caller on the fast packet
part of the network to a called party serviced through a legacy
switch 21, the incoming data packet arrives via one of the O/E
interfaces 111 or 115, and the interface sends the packet over the
bus 113 to the memory. The packet is written into an appropriate
location as directed by the control module 123. The control module
123 then instructs the appropriate TDM trunk interface 117 linked
to the legacy switch 21 serving the called party to read the packet
from the location in memory 125, via the low-speed bus 121. The
interface 117 converts telephone audio information in the packet to
the TDM format used by the office 21 and sends that audio
information over a TO channel on the link to that switch 21. The RT
11 implements a similar process, substantially in reverse, for
telephone data from the legacy end office switch 21 intended for
transport to a customer served via the fast packet communications
on the network rings. Signaling data generated in the RT 11 or in
other nodes of the network is transferred to and from the gateways
119 via the busses 113 and 121 and the memory 125, in the same
fashion.
The control module 123 also processes packets as necessary to
perform any translations required by particular network services.
For example, the control module 123 may recognize a particular
packet as a call request type signaling packet essentially
addressed to the RT 11. In response, the control module 123
analyzes the information in the packet, such as the source
identifier and the dialed digits, and determines how to respond to
the request. For example, the control module 123 may send queries
through the network to the MGC 33 or the like and receive
responsive instructions and then process the call based on those
instructions, as will be described in more detail later.
The HDTs 23 may utilize a structure similar to that of the
exemplary RT 11, but with interfaces and internal capacities
adapted to handle communications across a number of area rings 5
and the backbone ring 7. However, in most implementations of the
network, the HDTs 23 will not directly service any legacy switches
21, and as a result do not need to incorporate the low speed bus
and associated interfaces for the legacy switches. Hence, in most
deployments, the HDTs 23 will utilize a standard router design
having the appropriate optical ring interfaces and the capacity to
switch and route traffic of the appropriate levels.
A number of devices shown in the network diagram (FIG. 1) may be
implemented on general purpose computers controlled by software
programming. These include, for example, the MGC 33, the feature
server 31, the MOC 37, the platform implementing the provisioning
database 39 if separate, and the user data devices 17 such as PCs.
Although those familiar with data processing and telecommunications
arts will generally be familiar with such computers and their
associated software, it may be helpful to summarize the structural
and functional aspects thereof as they might relate to various
embodiments of the network of FIG. 1.
FIG. 4 is a functional block diagram of a PC or workstation type
implementation of a system 251. The system 251 may be a customer's
device, such as one of the data devices 17. However, for purposes
of the inventive network operations, a system such as 251 will
operate as a network computer, for example as the MOC 37, or
possibly the feature server 31 or the MGC 33.
The exemplary computer system 251 contains a central processing
unit (CPU) 252, memories 253 and an interconnect bus 254. The CPU
252 may contain a single microprocessor, or may contain a plurality
of microprocessors for configuring the computer system 252 as a
multi-processor system. The memories 253 include a main memory, a
read only memory, and mass storage devices such as various disk
drives, tape drives, etc. The main memory typically includes
dynamic random access memory (DRAM) and high-speed cache memory. In
operation, the main memory stores at least portions of instructions
and data for execution by the CPU 252.
The mass storage may include one or more magnetic disk or tape
drives or optical disk drives, for storing data and instructions
for use by CPU 252. For a PC type implementation, for example, at
least one mass storage system 255 in the form of a disk drive or
tape drive, stores the operating system and application software as
well as data. The mass storage 255 within the computer system 251
may also include one or more drives for various portable media,
such as a floppy disk, a compact disc read only memory (CD-ROM), or
an integrated circuit non-volatile memory adapter (i.e. PC-MCIA
adapter) to input and output data and code to and from the computer
system 251.
The system 251 also includes one or more input/output interfaces
for communications, shown by way of example as an interface 259 for
data communications via the network 1. The interface 259 may be a
modem, an Ethernet card or any other appropriate data
communications device. The physical communication links may be
optical, wired, or wireless (e.g., via satellite or cellular
network). For example, if located on a premises connected to a soft
NID 13, whether at a customer premises 9 or at a premises
specifically set-up as the Operations Center 35, this interface 259
can be any interface card that is compatible with the data link
implemented within the particular premises, for example a simple
local area network to a soft NID 13 or other network interface
device. Alternatively, if the system 251 connects directly to an
HDT, for example if the Operations Center 35 or the MGC 33 is
co-located with an HDT 23, then the interface 259 would be
compatible with the particular packet data link available from the
router implementing the particular HDT.
The computer system 251 may further include appropriate
input/output ports 256 for interconnection with a display 257 and a
keyboard 258 serving as the respective user interface. For example,
the computer may include a graphics subsystem to drive the output
display 257. The output display 257 may include a cathode ray tube
(CRT) display or liquid crystal display (LCD). Although not shown,
the PC type system typically would include a port for connection to
a printer. The input control devices for such an implementation of
the system 251 would include the keyboard 258 for inputting
alphanumeric and other key information. The input control devices
for the system may further include a cursor control device (not
shown), such as a mouse, a trackball, stylus, or cursor direction
keys. The links of the peripherals 257, 258 to the system 251 may
be wired connections or use wireless communications.
Each computer system 251 runs a variety of applications programs
and stores data, enabling one or more interactions via the user
interface, provided through elements such as 257 and 258, and/or
over the network 1 to implement the desired processing. The MOC 37,
for example, runs one or more programs for network monitoring
functions and/or service provisioning functions, and the MOC may
run a general purpose browser application and/or a separate e-mail
program, for normal business of the carrier's employees.
FIG. 5 is a functional block diagram of a general purpose computer
system 351 implemented as a server or the like, which may perform
the functions of the MGC 33 or the feature server 31. The exemplary
computer system 351 contains a central processing unit (CPU) 352,
memories 353 and an interconnect bus 354. The CPU 352 may contain a
single microprocessor, or may contain a plurality of
microprocessors for configuring the computer system 352 as a
multi-processor system. The memories 353 include a main memory, a
read only memory, and mass storage devices such as various disk
drives, tape drives, etc. The main memory typically includes
dynamic random access memory (DRAM) and high-speed cache memory. In
operation, the main memory stores at least portions of instructions
and data for execution by the CPU 352.
The mass storage may include one or more magnetic disk or tape
drives or optical disk drives, for storing data and instructions
for use by CPU 352. If used at the operations center 39, at least
one mass storage system 355, preferably in the form of a disk drive
or tape drive, stores the provisioning database 39. The mass
storage 355 may also include one or more drives for various
portable media, such as a floppy disk, a compact disc read only
memory (CD-ROM), or an integrated circuit non-volatile memory
adapter (i.e. PC-MCIA adapter) to input and output data and code to
and from the computer system 351.
The system 351 also includes one or more input/output interfaces
for communications, shown by way of example as an interface 359 for
data communications via the network 1. The interface 359 may be, an
Ethernet card or any other appropriate data communications device
providing a local link to an interface on the network 1. The local
physical communication links may be optical, wired, or wireless
(e.g., via satellite or cellular network). For example, if
connected to a soft NID 13, whether at a premises selected as the
location for the MGC 33 or the feature server 31, this interface
359 can be any interface card that is compatible with the data link
implemented within the particular premises, for example a simple
local area network. Alternatively, if the system 351 connects
directly to an HDT 23, for example if the feature server 31 or the
MGC 33 is co-located with an HDT 23, then the interface 359 would
be compatible with the particular packet data link available from
the router implementing the particular HDT.
The computer system 351 runs a variety of applications programs and
may store a database of control logic for either the MGC or the
feature server functions. Although not shown, the system 351 may
further include appropriate input/output ports for interconnection
with a local display and a keyboard or the like serving as a local
user interface for programming purposes. Alternatively, the
carrier's operations personnel may interact with the system 351 for
control and programming of the system from remote MOC 37 or other
terminal device, via a secure link through the network 1 or some
other appropriate network.
The components contained in the computer systems 251 and 351 are
those typically found in general purpose computer systems used as
servers, workstations, personal computers, network terminals, and
the like. In fact, these components are intended to represent a
broad category of such computer components that are well known in
the art.
The inventive concepts relate to networks having the multi-tiered
ring architecture and to methods and systems for implementing a
wide range of telecommunications services through such a network.
Certain aspects of the invention relate to the software elements,
such as the executable code and database for the service control
logic, which is implemented in the MGC 33 and other nodes of the
network, including the RTs 11, the HDTs 23 and the feature server
31. Other inventive concepts relate to programming or software for
application in the soft NIDs 13.
A software product includes at least one machine-readable medium
and information carried by the medium. The information carried by
the medium may be executable code, one or more databases and/or
information regarding the services or service control logic.
A computer readable medium, as used herein, may be any physical
element or carrier wave, which can bear instructions or code for
performing a sequence of steps in a machine-readable form or
associated data. Examples of physical forms of such media include
floppy disks, flexible disks, hard disks, magnetic tape, any other
magnetic medium, a CD-ROM, any other optical medium, a RAM, a ROM,
a PROM, an EPROM, a FLASH-EPROM, any other memory chip or
cartridge, as well as media bearing the software in a scannable
format. A carrier wave type of medium is any type of signal that
may carry digital information representative of the data or the
instructions or code for performing the sequence of steps. Such a
carrier wave may be received via a wireline or fiber-optic network,
via a modem, or as a radio-frequency or infrared signal, or any
other type of signal which a computer or the like may receive and
decode.
At different times all or portions of the executable code or data
for any or all of these software elements may reside in physical
media or be carried by electromagnetic media or be transported via
a variety of different media to program the particular system.
Physical media include the memory of the computer processing
systems 251, 351 or those of the soft NIDs 13, the remote terminals
11, the HDTs 21, the feature server 31 or the MGC 33. Examples of
such physical media include various semiconductor memories, tape
drives, disc drives and the like of general-purpose computer
systems. All or portions of the software may at times be
communicated through the network 1, through the Internet and/or
various other telecommunication networks to load appropriate
software into the appropriate node or system, for example to
program service logic and/or to provision a network node to
implement a service or feature for a particular customer. Thus,
another type of media that may bear the software elements includes
optical, electrical and electromagnetic waves, such as used across
physical interfaces between local devices, through wired and
optical landline networks and over various air-links.
As used herein, the term "computer-readable medium" therefore
refers to any medium that participates in providing instructions to
a processor for execution. Such a medium may take many forms,
including but not limited to, non-volatile media, volatile media,
and transmission media. Non-volatile media include, for example,
optical or magnetic disks, such as any of the storage devices in
the devices of FIGS. 4 and 5. Volatile media include dynamic
memory, such as main memory. Transmission media include coaxial
cables; copper wire and fiber optics, including the wires that
comprise a bus within a computer system. Transmission media can
also take the form of electric or electromagnetic signals, or
acoustic or light waves such as those generated during radio
frequency (RF) and infrared (IR) data communications. Common forms
of computer-readable media include, for example, a floppy disk, a
flexible disk, hard disk, magnetic tape, any other magnetic medium,
a CD-ROM, DVD, any other optical medium, punch cards, paper tape,
any other physical medium with patterns of holes, a RAM, a PROM,
and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a
carrier wave transporting data or instructions, or any other medium
from which a computer can read. Various forms of computer readable
media may be involved in carrying one or more sequences of one or
more instructions to a processor for execution.
It may be helpful, to consider an example of a simple call flow
process, as it might relate to a telephone communication through
the network 1. FIG. 6 is a signal flow diagram that may be useful
in understanding the processing of such a call.
For discussion purposes, assume that a user initiates a call (step
S1) from one of the analog telephone stations 15 by taking the
handset of the station off-hook. The telephone line card 53 in the
calling customer's soft NID 13 (originating) detects the off-hook
condition on the customer premises wiring 55 and transmits a
dialtone signal over the wiring 55 to the station 15 (S2). Upon
hearing the dialtone, the user dials the destination digits, for
example, by pushing the appropriate sequence of keys on the
telephone keypad. In most situations, the telephone 15 will
transmit dual tone multi-frequency signals over the wiring 55 to
the line card 53 (S3). The telephone line card 53 decodes these
tone signals to identify the dialed digits.
For at least the necessary signaling functions, the originating
soft NID 13 will have a `nailed-up` address for a link through the
ring 3 to the serving remote terminal RT 11. This nailed-up link
may be an assigned virtual circuit defined at the ATM level, if the
ring 3 uses ATM, and/or the signaling with the RT 11 may utilize an
IP address and TCP port identifier assigned to call-set up
signaling applications between the soft NID 13 and the RT 11. The
elements of the soft NID 13 formulate a packet and possibly ATM
cells containing segregated portions thereof, with dialed digits
and the appropriate addressing information; and the O/E interface
65 transmits that packet from the originating soft NID 13 through
the ring 3 to the serving RT 11 (S4).
Most addressing functions of the soft NID 13 are controlled by the
CPU 71. However, for call set-up using a nailed up link to the RT
11, the necessary link information may be permanently stored in
(burned into) the hardware of the telephone line card 53 and/or the
O/E interface 65, eliminating the need for CPU intervention.
When the RT 11 receives the dialed digits, it identifies the
originating soft NID 13 from the link and/or addressing information
contained in the packet. The dialed digit and source information
are internally routed to the appropriate application running in the
RT 11, for example, based on the TCP port number. In the telephone
service example, the RT 11 is the first point of translation. The
processing branches (S5) based on whether or not the control module
in the RT 11 detects a trigger, indicating a need to obtain data or
instructions from higher level service logic, typically that reside
in or accessible through the MGC 33.
For some calls, such as a call to a neighbor on the same ring 3,
the internal service logic programmed into the RT 11 may control
the call processing and provide any necessary translation between
the dialed digits and the necessary destination information to
route the call. In such a case, the decision in step S5 causes call
processing to branch to step S8.
However, if the internal logic is not sufficient by itself to
determine how to proceed, the call processing application in the RT
11 at step S5 branches to step S6, which triggers a query to higher
level network service logic. This is essentially an SSP type
function, i.e. to recognize a trigger event requiring higher-level
input and signaling the appropriate network node to obtain the
necessary input to complete the call processing. In the illustrated
embodiment, when it hits the triggering event at S5, the RT 11
launches a query through a permanent virtual circuit through the
network 1 to the MGC 33 (S6). The query contains the received
dialed digits as well as source information about the calling
customer's equipment/link. The source information may include
source address data from the signaling packet sent by the
originating soft NID 13 as well as supplemental data added by the
RT 11.
Upon receiving the query from the RT 11, the MGC 33 accesses stored
programs and associated service tables that define the network
service logic, as it should apply to the particular call. Some
aspects of this logic are service specific and apply to all
customers who subscribe to the particular service. Other aspects of
the logic may be subscriber specific and apply only to
communications to or from a particular subscriber. Based on its
network service logic, the MGC 33 formulates an appropriate
instruction and sends the instruction in a response message, back
through a virtual link through the network 1, to the serving RT 11
(S7). The instruction in the response message essentially tells the
RT 11 how to process the customer's telephone call request, for
example, how to provide the appropriate addressing information to
the soft NID if the call is to be completed as dialed. In response,
the RT 11 formulates a route message addressed to the originating
soft NID 13 and sends that message through the ring 3 (S8). The
route message, for example, provides the IP address currently used
by the terminating soft NID 13 (or of the RT link to a legacy end
office switch) and any other data necessary for setting up the
requested call through the network 1.
Upon receipt of the response message from the RT 11, the
originating soft NID 13 formulates an initial signaling message,
using data received from the RT 11, and sends that message through
the network 1 to the soft NID 13 of the called party, that is to
say, to the terminating soft NID 13 (S9). This initial signaling
message essentially indicates that the caller is attempting to call
a party at the destination premises, in a manner analogous to an
Initial Address Message (IAM) used in SS7 type interoffice
signaling. Since the message is specifically addressed to the
terminating soft NID 15, one or more of the RTs 15 and possibly one
or more HDTs 23 will simply route the packet(s) for that message
through to the appropriate local ring 3 and thus to the terminating
soft NID 15.
If the phone service is not available at the destination premises
at the time of the call, for example because the one internal line
is in-use, the terminating soft NID 13 returns a response
indicating that lack of availability. In response, the originating
soft NID 13 would apply a busy signal to the telephone line going
to the calling station 15.
For discussion purposes, assume that the phone service at the
called location is available. In that case, the terminating soft
NID 13 sends a response indicating that availability (S10). The
soft NID 13 at the destination applies ringing current to the local
customer premises wiring (S11), and the soft NID 13 at the calling
location plays ringback tone to the caller (S12). If someone
answers a telephone 15 at the destination (S13), then the
terminating soft NID 13 sends an appropriate message through the
network 1 to the originating soft NID 13 at the calling location
(S14). The soft NIDs 13 stop local signaling (ringing or ringback
tone) over the respective customer premises lines 55 and initiate
two-way communication of packetized audio information (S15).
In the illustrated example, if the logic in the RT 11 can dispose
of the call, then at step S5 there is no trigger event. As a
result, the process flow skips from S5 to S8 in the example above.
This situation occurs where the RT 11 already has sufficient data
to provide the route message (S8) to instruct the soft NID 13 how
to communicate with the terminating soft NID, for example if the
terminating subscriber receives service via the same local ring 3
or another local ring 3 coupled to the same RT 11.
Although not shown in the call flow for simplicity, if the soft NID
13 at the originating location has sufficient storage and
programming, then the CPU 71 in that unit may cache the
addressing/routing information for the call to this destination in
one of the memories 73. When the user subsequently dials the same
number, the CPU 71 could initiate the communications with the
destination, using the data from the cache, without the need to
again signal the RT 11, reducing the signaling load on the network
1.
In the simple example of FIG. 6, the telephone 15 was an analog
device or could have been an ISDN station. It is also possible to
make telephone calls through the network 1 using a voice over IP
type digital telephone, for example, coupled to the customer
premises data link 59. In such an implementation, more of the
intelligence for call set-up may reside in the phone itself,
instead of relying on the call processing intelligence in the soft
NID 13.
In the above-discussed call process flow, the RT 11 performed the
SSP functions. For some types of calls, the HDTs 23 may perform a
similar SSP function, for example, on in-bound calls intended for
destinations served via the subtending rings. Of particular note,
the logic in the RTs 11, the HDTs 23 and the MGC 33 is sufficient
to implement and control essentially all of the typical telephone
service features provided today to calling and called telephone
subscribers.
These network nodes will also implement service logic, as needed,
to control the other communications services through the network 1,
including digital broadband transport services. For example, when a
customer first initiates a data session with the ISP network 41 for
Internet access or the like, the serving RT 11 alone or in
combination with the logic of the MGC 33 may provide the necessary
information to establish packet data communications between the
soft NID 13 and the ISP network 41, in a manner similar to that
used in the telephone call processing outlined above. At the
customer premises, the session control may originate in the PC 17
or in the soft NID 13. Once the link to the ISP network 41 is
set-up, the PC 17 typically does all of the addressing, and the
soft-NID 13 functions simply as a pass-though device similar to a
high-speed modem.
In the telephone service example discussed above, both stations 15
connected to the network 1 via a soft NID 13 and a local ring 3.
However, in some cases, the caller or the called party may still be
using telephone equipment 15' connected to a legacy end office
switch 21. Processing of a call to or from such a station 15' will
flow in a manner similar to that of FIG. 6, except that the logic
and signaling functions of the respective soft NID are performed in
the RT 11 connected to the switch 21 and translated as appropriate
to extend signaling in an SS7 format over the link to that
office.
For example, if the calling station goes through a soft NID 13,
when the RT 11 returns the destination addressing information to
the soft NID, that information points to the particular RT 11
connected to the switch 21, instead of to another soft NID 13.
Subsequently, the signaling to establish the call will go through
that RT to and from the switch 21. To the originating soft NID 13,
the operation appears as described in the earlier example. However,
to the switch 21, the call set-up signaling uses the standard SS7
messages, and the voice call is established in the same manner as a
call coming in over a trunk from another office in the existing
telephone network. The RT 11 connected to the switch 21 also
performs the protocol conversions of the audio information between
the formats used over the fast packet network and by the soft NID
13 and the standard PCM/TDM formats used by the legacy switch
21.
To the legacy telephone systems, the fast packet network appears as
a combination of a tandem and an SS7 network of one or more
signaling transfer points. For calls originating at a station 15',
the switch 21 operates in the normal manner. The switch 21
communicates signaling in SS7 format over the link to the RT 11 and
through the network 1 to the destination resource. If the call goes
to a subscriber having a soft NID 13, the soft NID responds to any
appropriate signaling and establishes the logical call
connection.
If the outgoing legacy call is an interoffice call to station
served through another legacy switch (not shown) or requiring
inter-LATA transport through a network 29, the fast packet network
passes the SS7 signaling through and hands it off to the
appropriate legacy terminating system as unchanged SS7 messages.
The switch 21 thus signals the remote system exactly as in the
existing telephone network. Similarly, when the call is
established, the fast packet portions of the network provide
protocol conversions between the PCM/TDM of the switch 21 and the
network protocols at both ends, to pass the encoded audio
information through unchanged.
In the earlier discussion of the telephone call originating from
the station 15, the originating RT 11 recognized a trigger event
and initiated a query to the MGC 33 to obtain instructions or
information as to how to process the call. For some services, a
terminating RT 11 coupled to the switch 21 may perform a similar
query communication and call processing based on the response from
the MGC 33.
However, the legacy switch 21 has for some time been capable of
implementing Advanced Intelligent Network (AIN) services, and this
capability may be maintained in the network 1. For AIN services,
the switch 21 will detect a trigger and launch an SS7 query, as in
the existing AIN services on either outgoing or incoming calls or
both. However, the query goes over the SS7 link to the serving RT
11. The RT 11 and other fast packet elements of the network 1 will
pass the query through to the appropriate resource that serves as
the Service Control Point (SCP) for the AIN service in question.
The SCP function may simply be another application running on the
server that functions as the MGC 11, or the SCP may be a computer
coupled to the network 1 at any other convenient physical location
or a computer in a legacy telephone network 29. When the SCP
returns the AIN response message, in the appropriate Transaction
Capabilities Application Part (TCAP) SS7 format, the network 1
transports that message through to the RT 11, which strips the
message out of the network packets to recover the SS7 message. The
RT 11 then transmits the standard format SS7 TCAP response message
over the SS7 link to the switch 21, and the switch proceeds with
the AIN service processing of the call, in the normal manner.
For a virtual private network (VPN) service, the network nodes may
implement the necessary logic in a similar manner. However,
typically, this type of "private" service will utilize
pre-established logic narrowly defined in the programming of the
user locations intended to participate in the VPN and in the
interconnecting nodes. For example, if the network 1 uses ATM at
the lower protocol level, the VPU service may utilize a permanent
virtual circuit between the soft NID 13 at the customer premises 9
and the soft NID 13 coupled to the Intranet 43.
Those skilled in the art will recognize that the systems and
techniques outlined above have a broad range of applications, and
the embodiments admit of a wide range of modifications, without
departure from the inventive concepts. While the foregoing has
described what are considered to be the best mode and/or other
preferred embodiments, it is understood that various modifications
may be made therein and that the invention or inventions disclosed
herein may be implemented in various forms and embodiments, and
that they may be applied in numerous applications, only some of
which have been described herein. It is intended by the following
claims to claim any and all modifications and variations that fall
within the true scope of the inventive concepts.
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