Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1999-07-08
2004-03-30
Chin, Wellington (Department: 2664)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S395500, C370S410000
Reexamination Certificate
active
06714544
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to signalling the establishment of connections in connection oriented networks, for instance through the use of a management entity such as a call processor. More particularly, the invention relates to methods and apparatus for signalling the establishment of connections across ATM networks over a proxy signalling interface, for instance a user network interface or the like.
BACKGROUND OF THE INVENTION
Signalling protocols are often deployed to establish or set up connections so as to form an end to end path for a call in a communications network. Signalling in connection oriented networks is the process of establishing, maintaining and releasing a connection through the exchange of connection establishment request, connection acknowledgement, and connection clearing messages between the network elements along a given message path. At times, however, the originating calling equipment does not have the necessary network capabilities to signal a call in a given network through which a call must be routed. For instance, an intermediate network may not directly support the signalling protocols of the preceding and succeeding networks. As a result, an off-board call processor or network management device may be utilized to interface with the signalling of the proceeding and succeeding networks and to control the elements of the intermediate network. To control the intermediate network, the call processor or network manager must be able to efficiently establish connections across the intermediate network.
Communications networks may have particular or unique signalling protocols for setting up connections for calls, which signalling protocols may be unavailable to a succeeding network through which call establishment is to be propagated. In a communications environment of shared network resources, it is not uncommon for communication service providers to buy or rent access to bandwidth on a third party network from a network provider and use the third party network for the transmission of customer traffic. For instance, the introduction of competition in certain jurisdictions of the telephone industry has led to the creation of new competitors which are typically smaller or less capitalized than the former telephone monopolies. As well, these new competitors may sometimes offer more specialized or more restricted services than do the former monopolies. Often the newcomers to the telephone industry may not own end to end networks for carrying customer traffic. These newcomers may instead provide local networks that can connect customers to a backbone infrastructure, which in turn provisions connections to other local networks connected to the backbone. Alternatively, communication service providers may provide end to end communication systems but may wish to employ different types of networks within their systems. For example, a service provider may wish to establish local telephone networks employing traditional telephone communication technologies with interconnections between such networks being provisioned on high speed ATM networks. In all such cases, the signalling protocols of the various networks found along the call path may be incompatible or not supported from one network to another.
It is known in the art for a network management entity to be utilized in order to provision a connection path on behalf of another node across a connection oriented network. This may be implemented for purposes of establishing connections for or on behalf of equipment or networks which do not possess such capabilities, as described above, or for other reasons known to those skilled in this art. For example, it may be thought advantageous from the perspective of technology upgrades to dedicate the function of connection establishment and management to a network management entity. Typically, the goal of the network management entity is to provide path connectivity between ports in the network. The ports in question may be of various types, such as ATM ports, Frame Relay ports, Circuit Emulation ports, xDSL ports (such as ADSL, VDSL, HDSL and the like), and any other port types supported in the network being controlled. When the network management entity seeks to establish a path between two ports, it will normally dictate the channel number on each endpoint port. For example, the channel on a given port is a VPI/VCI for an ATM virtual circuit, a VPI only for an ATM virtual path, a DS0 for a T1 circuit emulation path, and a stream and DLCI for a frame relay path, to name but some examples.
Thus, when a given network is used to provide the backbone infrastructure for another originating network, it may be necessary to supply proxied connection establishment functions for the originating network. Whether for portions of the end to end call path which traverse the intermediate network or for the rest of the end to end path, the call set up is often administered on behalf of the originating network. This is typically done through an off board device or network management entity that is connected to the intermediate network. The off board device may be part of the signalling network for the originating network. The term “off board” means that the device is not necessarily part of a switch or node in the intermediate network. By way of specific example, off board devices are at times required for establishing connections across ATM networks on behalf telephone networks because telephone networks have not always been capable of performing signalling over typical ATM networks. Thus, call establishment, maintenance and tear down must be provided by a separate device such as an off board call processor. A signalling protocol typically used in telephone networks is the SS7 protocol. Currently, the SS7 protocol is often not supplied within an ATM network switch. Thus, in the specific example given above, the off board device would convert the SS7 signalling instructions into call setup instructions which are understood in the ATM network. It will be appreciated that various methods for setting up calls in an ATM network from an off board device are known to exist.
The communications system
10
of
FIG. 1
is a specific example of the use of an ATM network
12
as a backbone for an originating network such as a telephone network. The communications system
10
consists of first and second telephone networks
14
,
16
, the ATM network
12
and an SS7 signalling network
18
. The SS7 signalling network
18
provides call connection control for the telephone networks
14
,
16
. The SS7 signalling network
18
receives call setup requests from the telephone networks
14
,
16
and establishes connections for an end to end call path between the desired source and destination of the call by configuring the necessary switching in the nodes of the telephone networks
14
,
16
. The establishment of connections in communications networks using the SS7 protocol is well known to those skilled in the art. As explained previously, there are situations where it is desired to make a connection across the ATM network
12
in order to establish an end to end path for a call, for example in the event that a caller at a first telephone
20
connected to the first telephone network
14
wants to make a call to a person at a second telephone
22
connected to the second telephone network
16
, and where the ATM network may not directly support SS7 signalling. If so, another method is therefore necessary to establish such connections in the ATM network. Typically in these situations, an off board device such as a call processor or network management entity
24
is used to establish the connection across the ATM network
12
required to set up the call.
In some instances, the time that is required to set up proxied connections to define an end to end path for a call can affect network performance. The longer the time that is required to set up a call, the fewer calls that a network may set up every minute. In situations where hundreds or thousands of calls are required to be s
Bosloy Jonathan L.
Burns John C.
Tooker Mark
(Marks & Clerk)
Alcatel Canada Inc.
Chin Wellington
Schultz William
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