Lucent Technologies Inc.

At&t Bell Laboratories

Bay Microsystems, Inc.

Parama Networks, Inc.

Broadspider Networks, Inc.

Donald David Shugard

Walter M Pitio

Walter Michael Pitio

Yung-Terng Wang

Ramesh Nagarajan

George J Shevchuk

Glenn D Bergland

Song Chong

Hector Francisco Rodriguez

Peter Joseph Giacomini

Saul Joseph Einbinder

Robert C Pritchard

John V Camlet

David A Morano

Mark Katz

A distributed caching technique for use in computer networks is disclosed. The illustrative embodiment is particularly advantageous in computer networks that comprises a hierarchical topology because it removes some of the computational tasks associated with caching away from the network nodes that act as caches to other network nodes that are less burdened with computational tasks. Furthermore, some embodiments of the present invention use hash tables to facilitate the storage and retrieval of cached resources. The illustrative embodiment of the present invention comprises: hashing at a first processor a first resource identifier to create a hash key, wherein the first resource identifier identifies a first resource; transmitting from the first processor to a second processor the hash key and a request for the first resource; and receiving at the first processor a second resource in response to the transmission of the hash key and the request for the first resource from the first processor to the second processor.

Distributed caching architecture for computer networks

A reference timing architecture is disclosed that provides a level of flexibility that was not available with the architecture in the prior art. In particular, the present invention provides for multiple reference timing outputs that can be routed to equipment nodes relying on the timing information, wherein each of the timing processing paths that provide timing outputs can be controlled independently of one another.

Reference timing architecture

A deserializer is disclosed that incorporates a detection and feedback mechanism for ensuring that the deserializer samples a serialized stream of bits at advantageous times. Furthermore, a deserializer is disclosed that can operate at a frequency that is below the bit rate of the serialized stream of bits. The illustrative embodiment comprises: a first bi-stable storage device for receiving a first binary waveform and a first clock signal and for generating a second binary waveform based on the first binary waveform and on the first clock signal; a second bi-stable storage device for receiving the first binary waveform and a second clock signal and for generating a third binary waveform based on the first binary waveform and on the second clock signal; and unanimity logic for generating a fourth binary waveform based on a coincidence function of the second binary waveform and the third binary waveform.

Deserializer

In a switch fabric environment, which includes a buffer, packet data of different class-types from different sources is received, stored in the buffer, processed and outputted to its intended destination. As the buffer fills up, transmission from some of the data sources is stopped to avoid dropping of packets. To avoid packet loss, when the occupancy of the buffer reaches a first threshold value, further transmission of a first-class type of data is precluded from the particular source of that data then being received, while transmission from other sources of that same first-class type of data is not precluded from these other data sources until first-class type of data from such other sources is also received. Further, data of a second-class type is not precluded from being transmitted as long as the amount of data stored in the buffer remains below a second threshold, which is greater than the first threshold. When the occupancy of the buffer reaches that second threshold, further transmissions from the particular source of that second-class type of data then being received is also precluded. As data from other sources of that second-class type of data is received, further transmissions from those other sources are also precluded. A third-class type of data, however, is not precluded from transmission as long as the amount of data remains below a third threshold value, which is greater than the second threshold value. In order to avoid packet loss, when a packet from any source is received, it is stored regardless of whether transmission from the source of that packet has been precluded. Advantageously, a MAX/MIN distribution of the available bandwidth can be probabilistically achieved without packet loss.

Low-loss, fair bandwidth allocation flow control in a packet switch

A method and apparatus for recovering the time base of signals which change at periodic intervals is disclosed. The apparatus comprises gated voltage controlled oscillators (GVCO) that are alternated or exchanged, to reduce phase and frequency deviations in the recovered time base signal, such as the deviations induced by inherent GVCO differences. Each GVCO is stabilized by a respective phase locked loop. The respective GVCOs are gated only in response to a chosen polarity transition in the input signal, to make the circuit more tolerant of waveform distortions. More than two GVCOs may be used to provide improved frequency drift resistance. The circuit uses resynchronization control signals, such as the time slot signal in synchronous switching systems, to indicate resynchronization or reassignment of the GVCOs in gaps in the data transmission. Automatic reassignment is insured when there are periods of non-transitioning data that last longer than the stability of the GVCOs to prevent frequency drift in the recovered clock.

Method and apparatus for supplying synchronization signals securing as

An apparatus and method are disclosed for implementing a polarization-independent optical switch wherein switchable communication signals are retained in the optical mode while being switched between optical links in an optical communication network. The polarization-independent optical switch comprises polarization-dependent components which are advantageously arranged to switch arbitrary polarized light waves. The polarization-independent optical switch is achieved by splitting incoming arbitrary polarized light waves into two paths, a light wave with a TE radiation component and a light wave with a TM radiation component. The light wave with the TE radiation component is converted to a light wave with a TM radiation component. Both light waves having the TM radiation component are then switched in a polarization-dependent photonic switch device. The arbitrary light waves are recovered from the optical switch by converting one of the switched light waves having the TM radiation component to a light wave having the TE radiation component. The light wave with this TE radiation component is combined with the remaining switched light wave having the TM radiation component in a polarization combiner. As the polarization of the input light waves vary, more or less of the light wave energy will pass through the first path of the optical switch or the second path of the optical switch. The total amount of light wave energy through the optical switch, however, will remain relative constant.

Apparatus and method for providing a polarization independent optical

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Middletown, NJ, United States of America

Donald David Shugard