Ciena Corporation

Kevin S Meagher

John P Mateosky

Michael Y Frankel

Steven Arvo Surek

David W Boertjes

Gerard Leo Swinkels

James St Harley

David Miedema

Michel Belanger

Paul Littlewood

James Westdorp

Michael Vaughn

Victor Mizrahi

Loudon Thomas Blair

Steven W Cornelius

Steffen D Koehler

James M Allard

Michael S Brown

Jack Mateosky

A method, a controller, and an optical network element are configured to perform steps of monitoring one or more optical links each formed by optical transceivers which are configured to provide variable capacity via a plurality of modulation formats; based on the monitoring, causing corresponding optical transceivers for the one or more optical links to operate at a first modulation format different from a second modulation format providing excess capacity; and mapping the excess capacity to bandwidth useable by one or more services managed by the one or more of the management system, the management plane, and the control plane.

Systems and methods for managing excess optical capacity and margin in optical networks

A method, a network element, and a network include determining excess margin relative to margin needed to ensure performance at a nominal guaranteed rate associated with a flexible optical modem configured to communicate over an optical link; causing the flexible optical modem to consume most or all of the excess margin, wherein the capacity increased above the nominally guaranteed rate includes excess capacity; and mapping the excess capacity to one or more logical interfaces for use by a management system, management plane, and/or control plane. The logical interfaces can advantageously be used by the management system, management plane, and/or control plane as one of restoration bandwidths or short-lived bandwidth-on-demand (BOD) connections, such as sub-network connections (SNCs) or label switched paths (LSPs).

A fiber optic system includes a transmitter configured to utilize a plurality of modulation formats and a receiver communicatively coupled to the transmitter and configured to utilize a plurality of modulation formats. The transmitter and the receiver are cooperatively configured to set a modulation format of the plurality of modulation formats based upon optical signal-to-noise ratio associated therewith. A flexible bandwidth adaptation method includes monitoring at least one aspect of an optical link at a network element, responsive to the at least one aspect, computing a new modulation scheme for the optical link, and, if a solution is found for the new modulation scheme, changing to the new modulation format.

High speed optical communication systems and methods with flexible bandwidth adaptation

A method and system for transparent timing of an Ethernet signal over an optical transport network are disclosed. In one embodiment, a transceiver includes a first clock recovery circuit, a first synchronizer and an asynchronous mapper. The first clock recovery circuit recovers a first clock from a first signal received from an Ethernet network. The first synchronizer multiplies the first clock by a ratio M/N to produce a second clock to time a second signal transmitted over the optical transport network. M and N are integers. The asynchronous mapper maps frames of the first signal to produce frames of the second signal.

Transparent timing of a stratum synchronized ethernet signal using standard optical transport network rates

The present invention utilizes external synchronization to generate a completely standardized or functionally standardized optical transmission unit of level k (OTUk[V]) signal providing less jitter and wander build-up through a network of optical transport network (OTN) elements. This increases noise margins of transported signals and payloads. The present invention provides stratum-level synchronization utilizing a standards-based approach. In one embodiment of the present invention, rate adapters are included to provide m/n scaling of OTUk[V] signals to rates common in SONET and SDH synchronizers to provide line and loop distribution of timing through OTUk[V] signals. The present invention provides a choice of external synchronization sources including building integrated timing source (BITS), line, and loop timing sources. In another exemplary embodiment, the present invention provides multiple external references and automated timing protection switching for redundancy and reliability.

Externally synchronized optical transport network systems and associated methods

The present invention provides an Optical Transport Network (OTN) hierarchy that supports full transparency for both Ethernet and Telecom signals. The present invention defines new rates and mapping/multiplexing methods to adapt transparent 10 Gigabit Ethernet (10 GBE) (255/238 and 255/237) and 10 Gigabit Fibre Chanel (10 GFC) (255/237) to Optical Channel Transport Unit-3 (OTU3) at a higher rate. Additionally, the present invention defines new rates and mapping/multiplexing methods to adapt future transparent 100 GBE into an Optical Channel Transport Unit-4-extended (OTU4e) which is an OTU4 at a higher rate to support full transparency.

Optical transport network hierarchy for full transparent transport of datacom and telecom signals

The present invention provides frame-interleaving systems and methods for Optical Transport Unit K (OTUK) (i.e. Optical Transport Unit 4 (OTU4)), 100 Gb/s Ethernet (100 GbE), and other 100 Gb/s (100 G) optical transport enabling multi-level optical transmission. The frame-interleaving systems and methods of the present invention support the multiplexing of sub-rate clients, such as 10&#xd7;10 Gb/s (10 G) clients, 2&#xd7;40 Gb/s (40 G) plus 2&#xd7;10 G clients, etc., into two 50 Gb/s (50 G) transport signals, four 25 Gb/s (25 G) transport signals, etc. that are forward error correction (FEC) encoded and carried on a single wavelength to provide useful, efficient, and cost-effective 100 G optical transport solutions today. In one exemplary configuration, a 100 G client signal or 100 G aggregate client signal carried over two or more channels is frame-deinterleaved, followed by even/odd sub-channel FEC encoding and framing. In another exemplary configuration, a 100 G client signal or 100 G aggregate client signal carried over two or more channels is received and processed by a single 100 G FEC framer, followed by frame-deinterleaving into two or more sub-rate channels.

Frame-interleaving systems and methods for 100G optical transport enabling multi-level optical transmission

The present invention provides byte-interleaving systems and methods for Optical Transport Unit N (OTUN) (i.e. Optical Transport Unit 4 (OTU4)) and 100 Gb/s (100 G) optical transport enabling multi-level optical transmission. The byte-interleaving systems and methods of the present invention support the multiplexing of sub-rate clients, such as 10 Gb/s (10 G) clients, 40 Gb/s (40 G) clients, etc., into two 50 Gb/s (50 G) logical flows, for example, that can be forward error correction (FEC) encoded and carried on a single wavelength to provide useful, efficient, and cost-effective 100 G optical transport today. Signaling format support allows these two 50 G logical flows to be forward compatible with an evolving OTU4 and 100 G signaling format without waiting for optical and electronic technology advancement. Signaling format support also allows an evolving standard 100 G logical flow (i.e. OTU4, 100 Gb/s Ethernet (100 GbE), etc.) to be carried as 2&#xd7;50 G logical flows, 4&#xd7;25 G logical flows, or other lower rate formats on a single wavelength.

Byte-interleaving systems and methods for 100G optical transport enabling multi-level optical transmission

The present invention provides systems and methods for mapping and multiplexing wider clock tolerance signals in Optical Transport Network (OTN) transponders and multiplexers. In one exemplary embodiment, the present invention allows wide tolerance signals, such as a 10 GbE with a &#xb1;100 PPM clock tolerance, to be 100% transparently mapped asynchronously into OTU2-LAN rate transport signals. In another exemplary embodiment, the present invention allows wide tolerance signals, such as a 10 GbE with a &#xb1;100 PPM clock tolerance, to be 100% transparently multiplexed asynchronously in to OTU3-LAN rate transport signals. The present invention utilizes extra Negative Justification Opportunities (NJO) in either unused OPUk overhead or in OPUk payload area and Positive Justification Opportunities (PJO) in OPUk payload area. Advantageously, the extra NJO and PJO provide additional bandwidth for client data rate offsets beyond OTN specifications.

Systems and methods for mapping and multiplexing wider clock tolerance signals in optical transport network transponders and multiplexers

A semi-transparent time division multiplexer/demultiplexer that transmits low rate tributaries from one location to another using a high rate aggregate connection, while preserving substantially all of the TOH and payload for each tributary signal. Transparency of the tributary TOH is accomplished by interleaving both the TOH and the Payload of each tributary into the high rate aggregate signal. Some TOH bytes may be tunneled or re-mapped into unused/undefined TOH locations in the aggregate signal to allow transparency of the TOH without corrupting the aggregate. Errors may be handled by tunneling BIP bytes into unused/undefined aggregate locations and updating the tunneled bytes with error masks calculated at each network elements. Alternatively errors may be forwarded by using an error mask generated from the tributary BIP locations and inserting the mask into the associated aggregate BIP locations. The mask in the aggregate BIP is updated with error masks calculated at each network elements.

Semi-transparent time division multiplexer/demultiplexer

A semi-transparent time division multiplexer/demultiplexer that transmits low rate tributaries from one location to another using a high rate aggregate connection, while preserving substantially all of the TOH and payload for each tributary signal. Transparency of the tributary TOH is accomplished by interleaving both the TOH and the Payload of each tributary into the high rate aggregate signal. Some TOH bytes may be tunneled or re-mapped into unused/undefined TOH locations in the aggregate signal to allow transparency of the TOH without corrupting the aggregate. Errors may be handled by tunneling BIP bytes into unused/undefined aggregate locations and updating the tunneled bytes with error masks calculated at each network elements. Alternatively errors may be forwarded by using an error mask generated from the tributary BIP locations and inserting the mask into the associated aggregate BIP locations. The mask in the aggregate BIP is updated with error masks calculated at each network elements. Re-timing of TOH to a synchronized clock in the tributary framer circuits can be accomplished using controlled slips of overhead frames, whereby an entire frame is dropped or added depending on the relationship of the received clock and the synchronized clock. DCC bytes may be re-timed by adding or deleting flag bytes occurring between respective DCC packets. Re-timing of the aggregate TOH to a transmit clock may be accomplished in a similar manner.

A method for monitoring a plurality of components associated with a communications network node. A diagnostic service signal is generated at an intra-node component and transmitted along a first optical path to another intra-node component where the presence or absence of the signal is detected. In this manner, optical paths defined between intra-nodal components can be monitored using a diagnostic service signal.

Growing community of inventors

Bowie, MD, United States of America

Kevin S Meagher