Asynchronous Dual Mapping for Arbitrary Client Signals
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Solution Overview
Problem
SONET/SDH protocols require synchronous operation of intermediate network points, leading to increased costs due to the need for a master clock source and phase locked loop circuitry, which complicates network resilience and scalability.
Innovation Solution
Implementing a network architecture that asynchronously maps client signals into multiple frames (XTP, iXTF, XTF) with independent rates, allowing intermediate nodes to operate on fixed-rate frames without recovering the client signal, thus eliminating the need for synchronized clocks and simplifying hardware and software logic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If synchronous operation is implemented at intermediate network points, then network reliability is improved, but device complexity and cost increase due to master clock source and phase locked loop circuitry
Solution Approach 1:
The patent segments the network into ingress nodes that handle asynchronous mapping and egress nodes that handle synchronous operation, while intermediate nodes operate independently without requiring synchronization. This segmentation allows different parts of the network to operate at different rates, eliminating the need for complex clock synchronization infrastructure while maintaining overall network reliability.
Solution Approach 2:
The patent introduces fixed-rate frames as an intermediary between client signals and network transport. These frames act as a mediator that decouples the asynchronous client signal from the synchronous network infrastructure, allowing intermediate nodes to process data without requiring clock synchronization while maintaining reliable data transport.
2Reliability
If synchronous operation is implemented at intermediate network points, then network reliability is improved, but cost increases due to additional hardware and software requirements
Solution Approach 1:
The patent divides network functionality into specialized ingress and egress nodes that handle asynchronous mapping, while intermediate nodes use simple fixed-rate framing. This segmentation reduces the complexity and cost of intermediate nodes while maintaining reliability through the coordinated operation of edge nodes.
Solution Approach 2:
The patent employs simple, inexpensive fixed-rate frames as temporary containers that are created at ingress nodes and discarded at egress nodes. These disposable frames eliminate the need for expensive clock synchronization hardware at intermediate nodes while maintaining reliable data transport through the network.
3Adaptability or versatility
If asynchronous mapping is used, then adaptability to different client signal rates is improved, but device complexity increases due to additional mapping and recovery mechanisms
Solution Approach 1:
The patent segments the asynchronous mapping function into dedicated ingress nodes that perform the complex rate conversion and egress nodes that perform recovery. Intermediate nodes remain simple and rate-independent. This segmentation provides adaptability to various client signal rates while minimizing complexity at intermediate nodes.
Solution Approach 2:
The patent creates universal fixed-rate frames that can carry client signals of any rate independently. These frames serve multiple functions: they provide rate conversion at ingress nodes, serve as transport medium in the network, and enable recovery at egress nodes. This multi-functionality achieves adaptability without proportionally increasing complexity.
4Reliability
If clock synchronization infrastructure is deployed, then network reliability is improved, but scalability decreases due to additional synchronization requirements
Solution Approach 1:
The patent segments clock synchronization requirements to only the ingress and egress nodes, while intermediate nodes operate independently without synchronization. This segmentation enables network scalability by allowing new intermediate nodes to be added without requiring clock synchronization infrastructure, while maintaining reliability through the coordinated asynchronous operation at edges.
Data Source
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AI summary
A network may include an ingress node that is configured to receive a client signal having a client rate that is one of a multiple different client rates, asynchronously map the client signal into a first frame of a first rate, asynchronously map the first frame into a second frame of a second rate, and output the second frame on the network; an intermediate node that is configured to receive the second frame, recover the first frame from the second frame, asynchronously map the first frame into a third frame of a third rate, and output the third frame on the network, where the intermediate node does not recover the client signal from the first frame; and an egress node that is configured to receive the third frame, recover the first frame from the third frame, recover the client signal from the first frame, and output the client signal.