Multiplex communications – Pathfinding or routing – Through a circuit switch
Reexamination Certificate
1997-12-30
2001-02-13
Pham, Chi H. (Department: 2731)
Multiplex communications
Pathfinding or routing
Through a circuit switch
C370S360000, C370S486000
Reexamination Certificate
active
06188687
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to systems which process digital data. More specifically, the present invention relates to the high speed processing of synchronous data, such as may occur in a switch for a broadband network.
BACKGROUND OF THE INVENTION
Networks transfer electronic information between different locations. Broadband networks differ from other networks in that they transfer a relatively large amount of information during each unit of time. Future broadband networks are expected to convey video signals for business, educational and residential applications. Such networks may provide services such as broadcast-like video distribution, individual access to video program libraries, video telephone, video conferencing, and the like. Any one of such services may, for example, communicate signals having data transfer rates of up to 50 Mb/s or more.
In order to effectively serve a large number of customers, a broadband network includes switching nodes. At switching nodes, broadband signals are routed along selected paths so that desired signals are delivered from signal sources to targets.
Numerous problems are faced by a broadband, real-time switch that accommodates a large number of connections. These problems result, at least in part, from the high data transfer rates associated with broadband communications. In short, a tremendous amount of data need to be processed or otherwise transferred through the switch during every unit of time, and the larger the number of connections supported by the switch, the greater the amount of data which need to be processed.
A practical broadband switch should be able to efficiently support a variety of communication services, whether or not such services require unidirectional or bidirectional signal traffic. For example, although unidirectional broadcast-like services are currently available, bidirectional services such as video conferencing and other interactive services that utilize point-to-point connections may be in high demand in the near future. Unfortunately, switching systems designed to efficiently handle broadcast-like communications may not be capable of efficiently supporting bidirectional signal traffic, and vice versa. Such systems may not be able to adapt to long term trends in upstream and downstream signal traffic demand. In addition, conventional network switches may not be able to adapt to large or rapid variations in the amount of upstream versus downstream traffic.
An adaptable network switch may require less switching hardware than a rigidly designed switch having equivalent switching capabilities. A reduction in the number of physical components is desirable to conserve space and to lower engineering, manufacturing, and maintenance costs. For example, given a specific mix of upstream and downstream switching capacities, a switching circuit that adapts to upstream and downstream traffic volume requires fewer components than an equivalent switching circuit that employs a fixed number of upstream circuits and a fixed number of downstream circuits. If the actual volume of upstream and downstream traffic is not proportional to the respective number of fixed upstream and downstream circuits, then the circuits are not optimally allocated and switching capacity is wasted.
Switching capacity is also wasted when communication signals are delivered to a network switch without being requested from a downstream customer. Switching circuits become busy with signal traffic and the probability of blocking increases when signals are unnecessarily brought down to the network switch. The frequency of signal blocking can also increase if traffic volume is not evenly distributed among unoccupied or sparsely-occupied switching circuits. In addition, switching speed may be sacrificed if the network switch distributes signal traffic in a random or unstructured manner.
SUMMARY OF THE INVENTION
Accordingly, it is an advantage of the present invention that an improved broadband network switch is provided.
Another advantage of the present invention is that it provides a broadband switch that efficiently supports a variety of communication services.
A further advantage is that the present invention provides a broadband network switch that can adapt to large or rapid variations in upstream and downstream signal traffic.
Another advantage is that a broadband switch is provided that utilizes flexible switching circuits and switching processes.
A further advantage of the present invention is that a broadband switch that allocates upstream and downstream switching circuits according to upstream and downstream traffic demand is provided.
Another advantage of the present invention is that a method of operating a broadband switch is provided that efficiently manages and distributes signal traffic through the broadband switch.
Another advantage is that the probability of signal blocking is reduced in the broadband switch.
The above and other advantages of the present invention are carried out in one form by a method of operating a switching circuit to manage communication signal traffic. The method involves performing first stage switching in a first plurality of switching modules and performing second stage switching in a second plurality of switching modules. Each of the first switching modules is coupled to all of the second switching modules and the first and second switching modules are in data communication through a plurality of junctors. The method also involves directing communication signals through the junctors in response to upstream and downstream signal traffic volume.
REFERENCES:
patent: 3825690 (1974-07-01), Kelly et al.
patent: 4912700 (1990-03-01), Maddern et al.
patent: 5436890 (1995-07-01), Read et al.
patent: 5940738 (1999-08-01), Rao
Samalam et al., The Broadband Customer Service Module (B-CSM): An Access and Switching Module Serving SONET OC-12 Fiber Lines, IEEE, pp. 244-248, 1993.
Harry Mussman, “The Broadband Customer Service Module,” Access, GTE's Technology Magazine, Spring 1993.
Harry Mussman et al., The Broadband Customer Service Module (B-CSM) : An Access . . . Fiber Lines, Globecom, Nov. 30, 1993.
Lloyd R. Linnell, A Wide-Band Local Access System Using . . . Components, IEEE J. on Selected Areas in Comms., vol. SAC-4, #4, (Jul. 1986) pp. 612-618.
Steven Minzer, “A Signaling Protocol . . . Services,” IEEE J. on Selected Areas in Comms., vol. 9, #9 (Dec. 1991),pp.1383-1394.
Michael Cooperman et al., “Broadband Video Switching,” IEEE Communications Magazine, vol. 27, #12, Dec. 1989.
Andreas Weber et al., “Multichannel Circuit Switching—Networks,” IEEE J. on Selected Areas in Comms., vol. 9, #2 (Feb. 1991) pp. 226-232.
Chen Hung-San
Liu Stephen S.
Mussman Harry Edward
Duong Frank
Pham Chi H.
Suchyta Leonard Charles
Verizon Laboratories Inc.
LandOfFree
Broadband switch that manages traffic and method therefor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Broadband switch that manages traffic and method therefor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Broadband switch that manages traffic and method therefor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2611938