Abstract: A Forward Propagation Architecture is a novel switch architecture based on well-known unicast switching architectures, and provides two desirable properties: (1) no rearrangement of established calls is ever required and (2) the architecture is strictly non-blocking for multicast, even when multicast destinations are dynamically added to existing calls. These properties (excluding dynamic multicast destination addition) can be provided by standard architectures or Time:Space:Time architectures with speedup proportional to the width of the widest multicast to be supported. The speedup required by the FPA is constant and practical (approximately 4× speedup) and at significantly less hardware cost than n2 architectures. The key to the FPA's capability is a sequentially doubled fabric with a feedback loop. The FPA requires a routing algorithm for connection setting. The connection-setting algorithm is sufficiently simple to be implemented in hardware.

Abstract: Multicast call blocking is reduced in TST switch fabrics with the aid of an m-entry data structure. Each entry corresponds to one of m timeslots, and has 2n sub-entries corresponding to n input ports and n output ports. An N-cast call X:(y?z1, z2 . . . zN) is representable by associating a selected entry's yth input sub-entry with z1, z2, . . . zN of the selected entry's output sub-entries. Upon receipt of a call, the data structure entries are sequentially examined to detect the first entry for which a yth input sub-entry is unused and z1, z2, . . . zN output sub-entries are unused. If such an entry is detected, the call is scheduled for transmission in the corresponding timeslot. If there is no such entry and if N=1 the call cannot be scheduled; but, if N>1 the call is divided into two or more calls and an attempt is made to schedule them as above.

Abstract: A multicast connection scheduling method for a 3-stage switch fabric with n1 first stage, n2 second stage and n3 third stage interconnected switching devices. The first and third stage devices are non-blocking for unicast connections. The center stage devices are non-blocking for multicast connections. Load tables are provided for each center stage device, with one row per first and/or third stage device. Each row represents the number of connections being serviced between the first and/or third stage devices, through the center stage device corresponding to the table. By monitoring and updating the tables, the invention derives an approximately optimal connection schedule for an input list of connection requests, such that no input connection load exceeds any center stage device's maximum input connection load capacity and no output connection load exceeds any center stage device's maximum output connection load capacity.

Abstract: A method of adding a new connection (c, d) to a time:space:time switch fabric. The fabric has a set I of k input elements, a set M of m switch elements, and a set O of l output elements. Each input element contributes one input to each switch element, and each output element receives one output from each switch element. A state Sm characterizes the switch elements as a set of ordered pairs (i, j), where (i, j) ? Sm if and only if the jth output element is coupled to the ith input element through one of the switch elements. The range of Sm is the set of outputs of Sm such that if j ? range(Sm) then (i, j) ? Sm for some i ? I. The domain of Sm is the set of inputs of Sm such that if i ? domain(Sm) then (i, j) ? Sm for some j ? O.

Abstract: A time:space:time switch fabric incorporating an odd integer number of spatially distributed data switches and a plurality of spatially distributed data serializers. Each data switch has a first plurality of ingress ports, an equal plurality of egress ports, and a space switch for selectably interconnecting any one of the ingress ports to any one of the egress ports. Each data serializer has an input bus for receiving signals to be routed through the switch fabric, an output bus for outputting signals routed through the switch fabric, a plurality of egress ports selectably connectible to any one of the data switch ingress ports, and an equal plurality of ingress ports selectably connectible to any one of the data switch egress ports.

Abstract: A time:space:time switch fabric incorporating an odd integer number of spatially distributed data switches and a plurality of spatially distributed data serializers. Each data switch has a first plurality of ingress ports, an equal plurality of egress ports, and a space switch for selectably interconnecting any one of the ingress ports to any one of the egress ports. Each data serializer has an input bus for receiving signals to be routed through the switch fabric, an output bus for outputting signals routed through the switch fabric, a plurality of egress ports selectably connectible to any one of the data switch ingress ports, and an equal plurality of ingress ports selectably connectible to any one of the data switch egress ports.

Abstract: A method of adding a new connection (c, d) to a time:space:time switch fabric. The fabric has a set I of k input elements, a set M of m switch elements, and a set O of l output elements. Each input element contributes one input to each switch element, and each output element receives one output from each switch element. A state Sm characterizes the switch elements as a set of ordered pairs (i, j), where (i, j) &egr; Sm if and only if the jth output element is coupled to the ith input element through one of the switch elements. The range of Sm is the set of outputs of Sm such that if j &egr; range(Sm) then (i, j) &egr; Sm for some i &egr;I. The domain of Sm is the set of inputs of Sm such that if i &egr; domain(Sm) then (i, j) &egr; Sm for some j &egr; O. If a switch state Sm exists where c ∉ domain(Sm) and d ∉ range(Sm), then the new connection is added to Sm as (c, d).

Abstract: A filing module includes a box of relatively rigid material, projections extending outwardly from upper portions of front and rear panels of the box, and a pair of parallel rods secured to corresponding projections on the front and rear panels. The parallel rods are spaced to support hanging folders and function as carrying handles. A cover is hinged to the box by one of the rods and can be locked for security. The filing module can be placed in a standard file drawer or can be used independently. In one embodiment, a second pair of parallel rods is secured between end panels of the box to provide support for legal size hanging folders.

Abstract: A filing module includes a box of relatively rigid material, projections extending outwardly from upper portions of front and rear panels of the box and a pair of parallel rods secured to corresponding projections on the front and rear panels. The parallel rods are spaced to support hanging folders and function as carrying handles. A cover is hinged to the box by one of the rods and can be locked for security. The filing module can be placed in a standard file drawer or can be used independently. In one embodiment, a second pair of parallel rods is secured between end panels of the box to provide support for legal size hanging folders.