Optical Protection Switching Nodes With Efficient APS Overhead Encoding
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Solution Overview
Problem
Conventional optical transport networks waste overhead resources due to inefficient use of APS overhead encoding formats in shared mesh protection (SMP) technology, leading to low bandwidth utilization.
Innovation Solution
Optimized APS overhead encoding format that fully utilizes overhead resources by incorporating additional flags and bit allocations to indicate bridge and selector states, allowing efficient protection switching and recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional APS overhead encoding format is used in SMP technology, then protection switching can be implemented, but overhead resources are wasted due to unused reserved fields
Solution Approach 1:
The patent changes the parameter allocation in the APS overhead encoding format by redefining the usage of reserved fields. Specifically, it repurposes reserved bits (such as bits 28-31 in the K1 byte and bits 4-7 in the K2 byte) to carry additional protection switching information like bridge flag, selector flag, and timeslot indication, thereby fully utilizing the overhead resource structure without changing its fundamental 4-byte format
Solution Approach 2:
The patent makes the APS overhead structure multi-functional by enabling the same overhead fields to serve multiple purposes: the original protection switching indication function is preserved while adding functions for bridge/selector state indication and timeslot identification. This allows one overhead structure to handle multiple aspects of protection switching management simultaneously
2Productivity
If more overhead fields are utilized to indicate bridge and selector states, then protection switching efficiency improves, but overhead structure complexity increases
Solution Approach 1:
The patent segments the overhead information into distinct functional fields within the existing 4-byte structure. It divides the 32 bits into specific fields: request type (4 bits), service ID (8-10 bits), bridge flag (1 bit), selector flag (1 bit), timeslot indication (4 bits), and reserved bits. This segmentation organizes the information systematically, making the enhanced functionality manageable and implementable without overwhelming complexity
Data Source
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Figure 3
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AI summary
Embodiments of the present invention disclose a protection switching method, including: when a fault occurs on a working trail between a first end node and a second end node, sending, by the first end node, a first protection switching request message to an intermediate node, where a protection trail of the working trail includes the first end node, the second end node, and at least one intermediate node; and receiving, by the first end node, a second protection switching request message from the intermediate node, and switching service data to the protection trail for transmission, where one overhead frame of the first protection switching request message and the second protection request message includes at least two overhead information groups, and the overhead information group includes a request type field, a request signal identifier field, and a bridge flag field. One overhead frame of the first protection switching request message and the second protection request message can indicate overheads of two timeslots, so that overhead resource utilization is improved.