Systems and methods for compensating coherent optics delay asymmetry in a packet optical network
AssigneeCiena Corporation
InventorsBashar Abdullah, Daniel Perras, Sebastien Gareau, Xiaojin Liu
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Abstract
Systems and methods of compensating for the delay asymmetry of coherent optical modems in a packet optical network include measuring fill levels of one or more queues each including an elastic First-In-First-Out (FIFO) circuit used in a transport mapping scheme, wherein the transport mapping scheme is one or more of client mapping to Optical Transport Unit (OTU) and OTU mapping to Flexible OTN (FlexO); and performing adjustments in a clock based in part on the measured fill levels, wherein the adjustments are configured to reduce a Time Error (TE) in the packet network based on delay asymmetry between two nodes.
Claims18
A method of compensating coherent optical modems delay asymmetry in a packet optical network, comprising:
- obtaining measured fill levels of one or more queues each comprising an elastic First-In-First-Out (FIFO) circuit used in a transport mapping scheme, wherein the transport mapping scheme is one or more of client mapping to Optical Transport Unit (OTU) and OTU mapping to Flexible OTN (FlexO);
- and
- performing adjustments in a clock based in part on the measured fill levels, wherein the adjustments are configured to reduce a Time Error (TE) in the packet network based on delay asymmetry between two nodes
- wherein the measured fill levels are the measured fill levels at a first node for a first measurement and at a second node for a second measurement, wherein the adjustments comprise the first node adjusting its clock based on a difference between forward and reverse delays between the two nodes, determined based on the first measurement and the second measurement.
A coherent optical module, comprising:
- client-to-Optical Transport Unit (OTU) adaptation circuitry;
- OTU-to-Flexible OTN (FlexO) adaptation circuitry;
- Forward Error Correction (FEC) circuitry;
- and
- a Digital Signal Processor (DSP),
- wherein the client-to-OTU adaptation circuitry and the OTU-to-FlexO adaptation circuitry comprise one or more queues each comprising an elastic First-In-First-Out (FIFO) circuit used in a transport mapping scheme,
- wherein the adjustments are configured to reduce a Time Error (TE) in the packet network based on delay asymmetry between two nodes, and
- wherein the coherent optical module is configured to perform a first measurement of fill levels and to obtain a second measurement of fill levels from a second node and wherein a first node including the coherent optical module is configured to perform the adjustments on its clock based on a difference between forward and reverse delays between the first node and the second node, determined based on the first measurement and the second measurement.
A coherent optical module, comprising:
- client-to-Optical Transport Unit (OTU) adaptation circuitry;
- OTU-to-Flexible OTN (FlexO) adaptation circuitry;
- Forward Error Correction (FEC) circuitry;
- and
- a Digital Signal Processor (DSP),
- wherein the client-to-OTU adaptation circuitry and the OTU-to-FlexO adaptation circuitry comprise one or more queues each comprising an elastic First-In-First-Out (FIFO) circuit used in a transport mapping scheme,
- wherein fill levels of the one or more queues are measured and adjustments are performed to a clock based in part on the measured fill levels, wherein the adjustments are configured to reduce a Time Error (TE) in the packet network based on delay asymmetry between two nodes, and
- wherein the coherent optical module is configured to signal the adjustments to one or more nodes in the packet optical network.
Dependencies are inferred from the claim text.