Optical Line Terminal Logical Link Group Bandwidth Allocation
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Solution Overview
Problem
In IEEE Ethernet Passive Optical Network (EPON) and 10G-EPON systems, uplink bandwidth wastage occurs due to incomplete MAC frame transmission, leading to increased transmission delay, while in next-generation systems like 100G-EPON, fragmentation results in complex reassembly buffer requirements, increasing costs and potential packet loss.
Innovation Solution
The method involves dividing logical links into logical link groups and allocating bandwidth to share among them, allowing for efficient transmission of data frames and fragments, with scheduling algorithms to manage incomplete frames across bandwidths, reducing the need for large reassembly buffers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complete MAC frame transmission is enforced without fragmentation, then packet loss is prevented and simplicity is maintained, but bandwidth utilization deteriorates and transmission delay increases
Solution Approach 1:
The patent segments the MAC frame transmission process into multiple bandwidth allocations. Instead of requiring complete frame transmission in a single bandwidth, the frame is divided into multiple segments transmitted across different bandwidths. This is achieved by maintaining a buffer that stores incomplete frames and continues transmitting them in subsequent bandwidth allocations, thereby improving bandwidth utilization while preventing packet loss.
2Productivity
If MAC frame fragmentation is implemented to improve bandwidth utilization, then productivity increases, but device complexity increases due to reassembly buffer requirements
Solution Approach 1:
The patent merges the buffering functions of multiple logical links into a single unified buffer. Instead of requiring separate reassembly buffers for each logical link, the invention combines them into one shared buffer that handles fragmentation and reassembly for all logical links collectively. This significantly reduces the total buffer memory requirement and simplifies the device architecture while maintaining support for frame fragmentation across multiple bandwidths.
3Adaptability or versatility
If reassembly buffer size is increased to support more logical links, then adaptability increases, but cost increases
Solution Approach 1:
The patent implements a universal buffer that serves multiple logical links simultaneously. The single buffer is designed to handle fragmentation and reassembly for any number of logical links that share the same physical port, making it multi-functional. This universal approach allows the system to support a large number of logical links without proportionally increasing buffer memory, as the same buffer resources are shared across all logical links rather than having dedicated buffers for each.
Data Source
AI summary
A data transmission method includes steps described below. An optical line terminal (OLT) divides logical links supported by an optical network unit (ONU) into one or more logical link groups; and the OLT allocates a bandwidth to the logical link group of the ONU, so one or more logical links in the logical link group of the ONU share the bandwidth to transmit data.