Transparent Subwavelength Network Element Clock Fidelity
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Solution Overview
Problem
Current technologies, such as SONET, fail to transparently transmit client signals that follow the SONET protocol while maintaining timing integrity, and lack efficient designs for carrying sub-wavelength channels, which limits network flexibility and quality of service monitoring.
Innovation Solution
The Digital Wrapper standard is extended to create a tributary group from OTU1 frames, mapped onto 64 OTN tributary frames with di-byte interleaving, allowing for phase-offset compensation and modified pointer processing to maintain high clock fidelity and minimize jitter and wander, using multi-port equipment with optical port interfaces and programmable logic elements for quality monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SONET is used to transmit client signals, then quality of service monitoring is enabled, but transparent transmission of SONET client signals while maintaining timing integrity is not achieved
Solution Approach 1:
The patent segments the transmission system into multiple functional layers: the client signal layer (carrying SONET or other protocols transparently) and the transport layer (providing QoS monitoring and control). This is achieved through separate handling of client payloads and transport overhead, allowing independent optimization of each function without interference between them.
Solution Approach 2:
The patent introduces an intermediary transport mechanism that sits between the client signal and the network infrastructure. This intermediary layer provides QoS monitoring and control functions while leaving the client signal untouched, enabling both transparent transmission and service monitoring simultaneously through the mediator's dual functionality.
2Reliability
If SONET encapsulation is used to provide service guarantees, then quality of service monitoring is achieved, but bandwidth efficiency is reduced due to overhead
Solution Approach 1:
The patent applies local quality by providing QoS monitoring and control only where needed in the network infrastructure, rather than requiring full SONET encapsulation throughout the entire transmission path. This localized approach to service guarantee implementation reduces overall overhead while maintaining necessary quality controls at critical network nodes.
3Adaptability or versatility
If dark fiber is provided to customers, then network flexibility is improved, but quality of service monitoring capability is lost
Solution Approach 1:
The patent creates a universal transport mechanism that can handle multiple client protocols (SONET, dark fiber, or other signals) through a single infrastructure. This multi-functional system provides both the flexibility of dark fiber and the monitoring capabilities of managed services by implementing protocol-agnostic QoS monitoring at the transport layer.
4Ease of manufacture
If intermediate SONET rates are multiplexed into standard rates, then device compatibility is improved, but transmission precision and timing integrity are degraded
Solution Approach 1:
The patent employs dynamic rate adaptation mechanisms that allow the transport system to handle variable client signal rates without fixed multiplexing to standard SONET rates. This dynamic approach maintains timing integrity by preserving the original client signal characteristics while providing compatibility through flexible rate conversion and synchronization at network boundaries.
Data Source
AI summary
A network element for incorporating in nodes of a network that is a transparent, subwavelength networks. The element is configurable and adapted to support an arbitrary protocol, with protocol-specific monitoring features as well as protocol-independent add/drop capability. An arrangement that allows transmission of client signals with higher clock fidelity is achieved by developing a phases offset measure at an ingress node, communicating it to the egress node, and recovering the client's clock from the received data and from the received phase-offset information. The ability to recover the client's clock with high fidelity is enhanced by modified pointer processing in intermediate nodes of the network that the client's signal traverses. The pointer processing is modified to inject positive and negative justifications in excess of what is minimally necessary to insure proper transmission over a network that employs a protocol involving framing layer frames embedded in communication layer frames. Illustratively, the network protocol is an extended G.709 Digital Wrapper protocol, arranged to employ frames of 15240 columns by four rows.