Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1998-06-29
2002-04-09
Olms, Douglas (Department: 2732)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S221000, C370S235000, C370S254000, C370S465000
Reexamination Certificate
active
06370146
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of telecommunications and, more specifically, to a system for expansion of a telecommunications network with minimal disruption of traffic service on the network.
BACKGROUND OF THE INVENTION
A fundamental consideration in any telecommunications system design is switching capacity. Switching capacity must be analyzed in terms of current demand and projected demand in order to find a solution that is cost effective for both present and future service. For example, assume that a developing country is in the process of building a basic telecommunications system and intends to provide service to most of its current population. Such a population is most likely geographically distributed among small areas of high density (cities) and larger areas of low density (suburban and rural). In addition, the population is probably growing, but at different rates in different areas. Thus, the challenge for a telecommunications system designer is to provide sufficient switching capacity to support satisfactory service to most or all of the population while also anticipating likely increases in future demand and providing for economical expansion.
A second fundamental consideration in telecommunications system design is providing for the addition of new features or services in the future. Telecommunications equipment and service continues to evolve rapidly, due in large part to the advent of digital technology. Even more dramatic advances are likely in the future, particularly as previously separate industries such as the Internet, cable television and local telephone operating companies integrate services. Again, the challenge is to create a system which economically serves a present need, while also providing flexible and inexpensive ways to integrate new features and services as they become available. Ideally, such new features and services can be added to an existing system without disruption of service, but this has not always been possible.
Several of these fundamental considerations are addressed in a system described in commonly-assigned U.S. Pat. No. 5,544,163, Aug. 6, 1996, entitled EXPANDABLE TELECOMMUNICATIONS SYSTEM, which is incorporated herein in its entirety. Briefly, the patent describes an open, high speed, high bandwidth digital communications network for connecting multiple programmable telecommunications switches to form a large capacity, non-blocking switching system. In a preferred embodiment described therein, the network is implemented using one or more inter-nodal networks which provide a medium for transferring information over the network, and a plurality of programmable switches, each of which appears as a node on the network and serves a group of ports. Additional switches (nodes) may be added to the network as desired to increase the system's switching capacity.
Each node includes circuitry for transmitting and receiving variable-length, packetized information over the network, thus enabling each node to receive information from or transmit information to all other nodes. The network may carry any type of information present in the system including voice, data, video, multimedia, control, configuration and maintenance, and the bandwidth of the network may be divided or shared across various information types.
In addition, devices or resources other than programmable switches may also act as nodes on the network, thereby gaining direct access to all information passing through the network. More specifically, voice processing resources such as voice mail/message systems or other enhanced service platforms may, by becoming nodes, gain direct access to all ports served by the system without the need for a large central switch. The system's ability to transfer information of any type, in a readily usable form, at high speed across the network enables any service, feature or voice processing resource which is available at a given node to be provided to any port of the same or any other node.
The programmable switching nodes and the other nodes on an expandable telecommunications system are connected by a physical medium. When it is desired to modify an active inter-nodal network in order to enhance the services or increase the capacity provided by the system, by the inclusion of one or more additional nodes, the physical medium must be modified to accommodate an additional node. More specifically, the physical connections between the nodes in the inter-nodal network adjacent to the area to be expanded must be temporarily physically disconnected in order to connect the new node or nodes into the network. When the physical medium is disconnected, that portion of the inter-nodal network cannot, of course, carry telecommunications traffic. Typically, in such a case, the system, in whole or in part, must be taken out of service, thus leading to possibly unacceptable levels of service interruption.
Also, a new node which is added to the system must be properly configured before beginning operation to avoid undesired interference with other nodes.
There remains a need, therefore, for a telecommunications system which can be expanded by the addition of one or more new nodes with minimal, if any, disruption of telecommunications service provided by the system.
There remains a further need for a method of adding a new node to an existing, active system with essentially no interruption of service in the system.
SUMMARY OF THE INVENTION
These and other needs are satisfied by the present invention which provides, in brief summary, a method and system for non-disruptive addition of one or more nodes to an active inter-nodal network in a telecommunications system. In a preferred embodiment the invention is implemented in a method and an associated system which includes a plurality of interconnected nodes, which may be nodes used for telecommunications switching, or other nodes used for voice processing resources such as voice mail/messaging and the like. The nodes are interconnected by an inter-nodal network which carries packetized information among all the nodes served by the inter-nodal network.
Each node has an open mode of operation and a special mode of operation referred to as loopback mode. More specifically, each node has an “A” I/O port, which has its own transmit and receive coupling, and a “B” I/O port, which has its own transmit and receive coupling. In the open mode of operation, packets traverse between the node and the inter-nodal network by coming into the node through the receive coupling of the “A” port and exiting the node by the transmit coupling of the “B” I/O port. In loopback mode, one of the I/O ports is effectively disconnected from the system while the other “loops back” and functions to both transmit and receive packets using its own transmit and receive coupling and an alternate communication path to continue to pass packets onto and receive packets from the inter-nodal network.
A host is connected in communicating relationship with at least one of the nodes in the system. The host controls certain aspects of the system's operations by sending messages addressed to all nodes or specific messages to individual nodes. The system is also configured so that one of the nodes is a master node. The master node is capable of sending control messages addressed to the other, non-master, nodes in the network. In accordance with the invention, the master does this messaging, in part, by using a unique inter-nodal network control word. The inter-nodal network control word is a set of bits contained within a frame which in turn contains one or more packets originating from a particular node. In accordance with this aspect of the invention, a unique messaging sequence involves an interplay between messages issued by the host, which may be controlled by a user, and messages issued in turn by the master node, using the inter-nodal network control word. The inter-nodal network control word allows nodes to receive and execute instructions in a synchronized manner while avoiding the nec
Higgins Peter
Jazwierski Rafal J.
Cesari and McKenna LLP
Hom Shick
Olms Douglas
LandOfFree
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