Lucent Technologies Inc.

At&t Bell Laboratories

At+t Corp.

Philip Sidney Dietz

Mark A Bordogna

Joseph Elide Landry

Warren Clifton Trested, Jr

Jeffrey Robert Towne

Lo C Nguyen

Robert C Brockway

Warren Clifton Trested

Mark Aldo Bordogna

Distributed switch fabrics can support multiple switching functions while meeting established performance requirements by using a control architecture based on multiple layers of signal status carried within signals transported through the distributed switch fabrics. More specifically, a method and apparatus is provided for controlling the selection of signals through distributed switch fabrics by deriving signal status information for the signals at any point along a transmission path and embedding the signal status information in each of the signals using multiple signal status layers. Each of the signals carries its respective signal status information as it propagates along the transmission path, so that the embedded signal status information can be selectively extracted from any of the multiple signal status layers to facilitate a selection decision at any of the distributed switch fabrics. The multiple layers of signal status can be used to provide a cumulative signal status of a particular signal as it propagates along the transmission path or the multiple layers can be used to support various combinations of status control, such as each layer being used to track a different level or type of status for the signal.

Control architecture using a multi-layer embedded signal status protocol

A simple, elementary switch fabric is provided for switching individual signals as a composite group based on group signal status that is embedded and carried within each of the individual signals in the group. In general, a group signal status is derived for a group based on the signal status of each of the individual signals within that group. This group signal status is then individually encoded and embedded in each of the individual signals in the group. The embedded group signal status can be extracted and decoded at any point within the transmission path, as necessary, to facilitate appropriate switching decisions. Although each individual signal is switched independently by the elementary switch fabric, the individual signals are effectively switched as a composite group because the switching decision for each individual signal in the group is based on the same group signal status. That is, individual signals in a particular group will either be selected or rejected together as a single, composite group.

Method and apparatus for switching signals using an embedded group signal status

A system for providing segmented control of a single, homogeneous routing structure, such as a switch fabric, includes application control elements that are each responsive to embedded signal status information for each of the input signals to the switch fabric. Within each of the application control elements, a configurable arrangement of selectors and control logic is used to provide domain segmented control of each of the separate switching functions for a particular application. Each application control element performs an application specific address resolution function to resolve a single address of one of the input signals based on the embedded signal status of each of the input signals. This single address is provided to the switch fabric so that the corresponding input signal can be selected at the switch fabric output. Because embedded signal status is provided locally at each selection point within the application control element, the control functions for each of the separate switching functions are decoupled, and, as a result, each of the separate switching functions can be independently controlled as a separate domain within the application control element. The single, homogeneous switch fabric simultaneously supports multiple applications in parallel because each of the application control elements is used to control a separate output from the switch fabric. Because of the one for one association between application control elements and switch fabric outputs, the switch fabric is effectively 'channelized' whereby each channel of the switch fabric supports a separate application.

Control architecture for a homogeneous routing structure

A network element with a centralized switch fabric is able to support multiple switching functions while meeting established performance requirements by using a control system based on an embedded signal status protocol. Generally, each input signal within a transmission path is monitored to derive signal status information, which is then individually encoded and embedded within the input signal. The embedded signal status can be decoded and provided as input to control logic for processing at any point within the transmission path, as necessary. In the case of a centralized switch fabric, the control logic resolves an address of a single input signal based on the embedded signal status and provides this resolved address to the switch fabric so that the appropriate input signal can be selected. In the present invention, the control logic may be configured to support any given application, e.g., 'path-in-line' protection switching, whereby each configuration of control logic constitutes an application control set that supports the performance requirements of that given application.

Control architecture using an embedded signal status protocol

An equipment unit latch and an associated switch arrangement are advantageously employed to generate an action initiation signal upon initial movement of the latch toward physically removing the equipment from an equipment frame but prior to any movement of the equipment unit in an equipment frame in which it is inserted. The physical shape and dimensions of the latch and the spatial relationship of the associated switch arrangement to the latch are such that the latch is allowed to move a sufficient distance toward removing the equipment unit from the equipment frame, in order to activate the switch to generate the action initiation signal prior to any movement of the equipment unit in the equipment frame. In a specific embodiment of the invention, the switch includes a light emitter and a light detector. Light from the emitter is inhibited from reaching the detector by the latch when the equipment unit is fully inserted in the equipment frame and the latch is in a closed position. Upon movement of the latch, the light is no longer inhibited from being detected by the detector and the action initiation signal is generated after movement of the latch, but prior to any movement of the equipment unit toward being removed from the equipment frame.

Equipment unit latch and associated switch

An equipment unit protection switch from an in-service equipment unit to a standby equipment unit is realized prior to any movement of the active equipment unit about to be removed from an equipment frame in which it is inserted. This is achieved by advantageously incorporating apparatus for generating an equipment unit removal indication signal that enables a controller to anticipate the removal of the equipment unit from the equipment frame. To this end, the equipment units employ an equipment unit latch and an associated switch to generate the equipment removal indication signal. Initial movement of the latch causes the equipment unit removal indication signal to be generated prior to any movement of the equipment unit in the frame in which it is inserted.

Growing community of inventors

East Hampstead, NH, United States of America

Philip Sidney Dietz