Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
2000-01-21
2004-11-30
Vu, Huy D. (Department: 2665)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S410000
Reexamination Certificate
active
06826190
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention lies in the field of communications. The invention relates to a method for controlling a network node in a telecommunications network, a method for controlling a telecommunications network, and a network node. The invention can be used in all application areas in which data or data streams are to be distributed to a plurality of users and/or terminals, and, in particular, where point-to-multipoint connections are to be made available.
The invention is particularly provided for use in teleparticipation applications, i.e., where a user participates in a live event, for example, a sporting event or a discussion, by telecommunication, the intention being that the subscriber will receive at least as much information as if he were personally present. Further possible applications of the invention are, for example, the dissemination of television or video channels to potentially very large groups of recipients (i.e., “pay TV” and “video on demand”).
Asynchronous Transfer Mode (“ATM”) networks, such as are specified in the documents of the ATM Forum, have a plurality of network nodes and a plurality of terminals. In ATM networks, point-to-multipoint connections can be formed by a root structure over a plurality of network nodes, each of these network nodes forwarding at least one incoming data stream, respectively, to at least one other network node and/or at least one terminal. See Recommendation ITU-T Q.2971 of the International Telecommunication Union. In addition, the document “ATM user-network interface signaling specification” of the ATM Forum (number af-sig-0061.000, July 1996, section 6) describes a process of participation in such a connection initiated by the datasink (“leaf initiated join”).
Such means could, in principle, be used to make available a teleparticipation application. However, the method is very costly because two subscriber processes have to be managed for each connected subscriber in each network node through which the connection runs. The subscriber processes communicate with one another with special, subscriber-related messages.
The subscriber processes are also carried out in network nodes that are not connected to terminals but merely forward information to other network nodes. The quantity of information that is to be managed increases exponentially with increasing proximity to the data source (leaf of the root) because the network nodes that are involved in a point-to-multipoint connection form a root structure. For mass applications (for example, the transmission of sporting events with a large number of camera perspectives), the method cannot be used. The method is also unnecessarily complex for a large number of other applications.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method for controlling a network node or a telecommunications network, and a network node that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and that make possible the desired distribution of data streams at low cost, and that can also be used economically, particularly for mass applications or for applications with a large number of network nodes involved in a connection.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a method for controlling a network node in a telecommunications network having a plurality of network nodes and a plurality of terminals for a teleparticipation application, including the steps of providing network node with a plurality of interfaces, forwarding at least one incoming data stream from the network node to at least one of a group consisting of at least one further network node and at least one terminal, maintaining, through the network node, a connection data stock with connection-related information that is used to control existing connections to other network nodes of the telecommunications network, and indicating, through the connection data stock, at least a data stream designator for an interface and for a data stream that is incoming or outgoing at the interface and a direction of the data stream.
In accordance with another mode of the invention, there is provided a step of updating the connection data stock only if the network node receives a SETUP message or a message signaling a connection release.
In accordance with a further mode of the invention, there is provided a step of establishing, in reaction to a reception of a SETUP message at an interface ix with a data stream designator g, a connection between an interface iy and the interface ix, in which case either a data stream with the data stream designator g is already received at the interface iy or the SETUP message is forwarded through the interface iy in order to request a setup of a connection for such a data stream.
In accordance with an added mode of the invention, the following steps are performed when a SETUP message is received at an interface ix with a data stream designator g: updating the connection data stock by entering a data stream that is outgoing at the interface ix with the data stream designator g; if there is no incoming data stream with the data stream designator g entered in the connection data stock, selecting an interface iy, forwarding the SETUP message through the interface iy, and updating the connection data stock by entering an incoming data stream at the interface iy with the data stream designator g; and forwarding the data stream that is incoming at the interface iy and has the data stream designator g to the interface ix in accordance with the connection data stock.
In accordance with an additional mode of the invention, there are provided the steps of releasing an existing connection between an interface iy, at which a data stream with the data stream designator g is incoming, and an interface ix when a RELEASE message is received at the interface ix with a data stream designator g, the RELEASE message signaling a connection release initiated by a datasink, and forwarding the RELEASE message through the interface iy if the interface ix was the only interface to which the data stream with the data stream designator g was forwarded for outputting.
In accordance with yet another mode of the invention, the following steps are performed when a RELEASE message is received at an interface ix with a data stream designator g, the RELEASE message signaling a connection release initiated by a datasink: terminating the forwarding of the data stream with the data stream designator g to the interface ix; updating the connection data stock by removing the entry that refers to the interface ix and the data stream with the data stream designator g; and if no further outgoing data stream with the data stream designator g is entered in the connection data stock, forwarding the RELEASE message to that interface iy at which the data stream with the data stream designator g is incoming, and updating the connection data stock by removing the entry referring to the interface iy and the data stream with the data stream designator g.
In accordance with yet a further mode of the invention, the following steps are performed when a message is received that signals a connection release initiated by a data source, the message being received with a data stream designator g: terminating the forwarding of the data stream with the data stream designator g; forwarding the message to all the interfaces through which the data stream with the data stream designator g has been output; and updating the connection data stock by removing all the entries referring to the data stream designator g.
With the objects of the invention in view, there is also provided a method for controlling a telecommunications network having a plurality of network nodes and a plurality of terminals, including the steps of using at least one of the terminals as a data source and at least one of the terminals as a datasink, forwarding, through each network node, at least one incoming data strea
Greenberg Laurence A.
Locher Ralph E.
Ryman Daniel
Siemens Aktiengesellschaft
Stemer Werner H.
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