Calix Limited

Calix Networks, Inc.

David Cleary

Christopher D Koch

Mark Richard Biegert

Peter O Lee

In general, techniques are described for efficient management of ring networks with a system of two network devices. The first network device of the ring network is designated as an adjacent selective forwarding (ASF) device, and the second network device is designated as a master device. The master device monitors the ring network to determine whether a fault has occurred in the ring network and transmits via a secondary port of the master device a network status message to the ASF device based on the determination of whether the fault has occurred. The ASF device determines a status of the ring network based on the network status message and selectively forwards data traffic to the master network device based on the determination of the status. As a result, the master device more efficiently utilizes network resources by not consuming processor or memory resources to prevent traffic loops.

Efficient management of ring networks

This disclosure relates to detection of optical fiber failure and implementation of protection switching in a passive optical network (PON). A protection switch determines whether there is an optical fiber failure in a fiber link between an OLT and a group of ONTs. In the case of an optical fiber failure, an optical fiber may be physically cut or damaged, causing the optical fiber link to be disabled. A protection switch may detect an optical fiber failure by determining a peak optical power of at least a portion of an upstream optical signal transmitted from one or more ONTs via the optical fiber link. If the peak optical power is less than a threshold value, the protection switch may detect a fiber failure. In response to a detected fiber failure, the protection switch may switch upstream and downstream PON transmissions from a primary optical fiber to a secondary optical fiber.

Passive optical network protection switching

Techniques are described for managing traffic flow to an optical network terminal (ONT) on a passive optical network (PON) to prevent an individual ONT from being overrun. Specifically, the techniques involve reducing a transmission rate of a unique traffic flow and selectively denying access to a common traffic flow. By reducing the transmission rate of the unique traffic flow, sufficient bandwidth may be released to receive the unique traffic flow and the common traffic flow without overflowing the ONT. For example, the ONT or, alternatively, the OLT may send the requested common traffic flow without reducing the transmission rate of the unique traffic flow when sufficient bandwidth is available, send the common traffic flow but reduce the transmission rate of unique traffic flow by an appropriate amount, or deny access to the common traffic flow altogether without reducing the transmission rate of the unique traffic flow.

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Bloomington, MN, United States of America

David Cleary