TDM Traffic Accommodation in EPON via Segmentation and Windowed Transmission
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Solution Overview
Problem
Current Ethernet passive optical networks (EPONs) are unable to seamlessly carry time-division multiplexed (TDM) traffic while meeting stringent quality-of-service (QoS) requirements, particularly due to issues with jitter and latency.
Innovation Solution
A system that receives and stores TDM data in segmentation buffers, encapsulates it into packets, and transmits them during designated transmission windows, using Real-Time Transport Protocol (RTP) headers for timestamping and Pseudo Wire Emulation Edge to Edge (PWE3) frames to manage data, thereby reducing jitter and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If TDM traffic is carried in EPON using conventional packet switching, then network capacity and flexibility are improved, but jitter and latency increase violating QoS requirements
Solution Approach 1:
The patent segments the TDM traffic into discrete packets with timestamps, allowing the asynchronous packet-switched EPON network to handle TDM traffic while maintaining QoS. The segmentation buffer divides the continuous TDM stream into manageable units that can be transmitted during scheduled windows.
Solution Approach 2:
The patent applies preliminary action by pre-allocating transmission time slots for TDM traffic and pre-buffering packets in the segmentation buffer before the designated transmission window. This ensures that TDM traffic is transmitted at the correct time without waiting for the actual transmission slot.
2Reliability
If TDM data is buffered and transmitted during designated windows, then QoS requirements are met, but transmission time is increased
Solution Approach 1:
The system performs preliminary buffering of TDM data in the segmentation buffer before the designated transmission window. By pre-assembling packets and preparing them in advance, the system minimizes the actual transmission time during the allocated slot while still meeting QoS requirements through timestamp-based synchronization.
Solution Approach 2:
The patent uses timestamps in the packet headers as feedback mechanisms to track the actual transmission time versus the scheduled time. This feedback allows the receiving end to resynchronize and maintain proper timing without requiring excessive buffer time, thereby reducing overall transmission time while preserving QoS.
Data Source
AI summary
One embodiment of the present invention provides a system for accommodating time-division multiplexing (TDM) traffic in an Ethernet passive optical network (EPON). During operation, the system receives data from an upstream TDM channel at a remote node and stores received data in a segmentation buffer. The system encapsulates the data stored in the segmentation buffer into a packet. The system receives a message from the central node granting a TDM transmission window starting at a designated time. The system further communicates the packet to an upstream transmission mechanism within the remote node before the designated time, and transmits to the central node an upstream frame containing the packet at the designated time.