Ethernet Timing Markers for Synchronization Transport
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Solution Overview
Problem
Current networks, particularly Ethernet and Optical Transport Networks (OTN), lack the capability to carry synchronization signals effectively, as they are asynchronous and do not support the distribution of stratum clocks, posing challenges for service providers transitioning away from SONET/SDH systems.
Innovation Solution
The introduction of special timing markers within Ethernet and OTN frames allows for the transportation of synchronization signals over asynchronous Ethernet and OTN streams, enabling the creation of standard Ethernet with timing capabilities and frame decomposition into fixed and excess bandwidth, facilitating deterministic bandwidth allocation and user isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Ethernet and OTN networks are used as common transport technology, then network evolution and cost-effectiveness are improved, but the capability to carry synchronization signals is lost
Solution Approach 1:
The Ethernet frame is segmented to include a dedicated timing marker field that carries synchronization information separately from the data payload. This allows the network to maintain its asynchronous Ethernet nature while embedding synchronous timing signals within the frame structure, resolving the contradiction between using standard Ethernet and carrying sync signals.
Solution Approach 2:
A timing marker serves as an intermediary element embedded within the Ethernet frame that mediates between the asynchronous Ethernet transport and the synchronous timing requirements. The timing marker carries the synchronization signal through the asynchronous network without requiring the entire network protocol to be synchronous.
2Adaptability or versatility
If adaptive clock recovery over PWE3 is used, then soft clock distribution is enabled, but clock quality and reliability deteriorate
Solution Approach 1:
Instead of recovering the clock adaptively at the receiving end, the synchronization signal and timing information are preliminarily embedded in the Ethernet frame's timing marker field before transmission. This ensures high-quality timing information is preserved throughout the network without relying on adaptive recovery processes that degrade clock quality.
3Productivity
If frame decomposition of Ethernet packet is implemented, then deterministic bandwidth allocation and user isolation are achieved, but device complexity increases
Solution Approach 1:
The Ethernet frame is segmented into distinct regions including a timing marker field and data payload, with the timing marker positioned at a fixed offset. This segmentation enables deterministic bandwidth allocation and user isolation while maintaining relatively simple device implementation through fixed-position field extraction and insertion.
Data Source
AI summary
The present invention reserves special Ethernet timing packets to mark timing within Ethernet and OTN, and secondarily creates frames within the Ethernet stream through the timing marker packets. The result is standard Ethernet with timing capability that can be transported over standard Ethernet links and/or within OTN. This timing capability can be utilized to carry synchronization over asynchronous Ethernet and OTN streams. Advantageously, enabling Ethernet and OTN to carry synchronous information will de-risk switching from SONET/SDH to Ethernet and/or OTN for service providers. The present invention also includes frame decomposition of the Ethernet stream. Ethernet packets are broken into fixed bandwidth and excess bandwidth. The fixed bandwidth is subdivided into fixed (negotiated) flits, with each flit corresponding to a specific user or combination of users like a private tunnel. This offers service providers a method to provide deterministic and more secure bandwidth over Ethernet to multiple clients.