PON Scheduling via Modified MPCP Frames
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Solution Overview
Problem
Current Ethernet passive optical networks (EPONs) face challenges in managing upstream traffic efficiently, particularly in extended PONs with longer reaches and higher densities, where congestion and packet loss occur due to limited buffering and power constraints, and existing solutions like large traffic management chips are costly and power-intensive.
Innovation Solution
The implementation of a low-cost, low-power Ethernet switch with modified Multi-Point Control Protocol (MPCP) control frames that schedule upstream traffic using VLAN tags or unicast destination addresses, allowing for efficient bandwidth management and reduced congestion without the need for extensive buffering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional traffic management systems with extensive buffering are used, then packet loss and congestion are reduced, but cost and power consumption increase significantly
Solution Approach 1:
The patent extracts the traffic management functionality from the Ethernet switch and places it in the OLT. This allows the use of simple, low-power Ethernet switches without extensive buffering capabilities, while the OLT handles the complex scheduling and traffic management functions through modified MPCP protocols.
Solution Approach 2:
The patent introduces modified MPCP control frames as an intermediary mechanism between the OLT and ONUs. These control frames enable the OLT to schedule upstream traffic and manage buffer usage efficiently, allowing simple Ethernet switches to function effectively in extended PONs without requiring complex traffic management hardware.
2Ease of manufacture
If simple Ethernet switches with limited buffering are used, then cost and power consumption are reduced, but congestion and packet loss occur
Solution Approach 1:
The patent extracts the traffic management functionality from the Ethernet switch and places it in the OLT. This allows the use of simple, low-power Ethernet switches without extensive buffering capabilities, while the OLT handles the complex scheduling and traffic management functions through modified MPCP protocols.
Solution Approach 2:
The OLT performs preliminary scheduling actions by sending modified GATE control frames to ONUs before upstream transmission occurs. This preliminary scheduling allocates upstream bandwidth and buffer usage in advance, preventing congestion at the Ethernet switch even though the switch has limited buffering capabilities.
3Reliability
If buffering capacity is increased to prevent packet loss, then reliability improves, but device complexity and cost increase
Solution Approach 1:
The patent extracts the traffic management functionality from the Ethernet switch and places it in the OLT. This allows the use of simple, low-power Ethernet switches without extensive buffering capabilities, while the OLT handles the complex scheduling and traffic management functions through modified MPCP protocols.
Solution Approach 2:
The patent implements self-service buffer management where each ONU monitors its own buffer status and reports to the OLT using modified REPORT control frames. The OLT uses this information to dynamically adjust scheduling decisions, allowing the system to manage packet loss prevention through coordination rather than extensive buffering hardware.
4Adaptability or versatility
If standard MPCP control frames are used, then protocol compatibility is maintained, but scheduling efficiency in extended PONs is reduced
Solution Approach 1:
The patent modifies existing MPCP control frame parameters to carry additional scheduling information needed for extended PONs. Specifically, it uses VLAN tags and unicast destination addresses in the modified control frames to enable efficient scheduling of multiple remote PONs while maintaining compatibility with standard Ethernet switching infrastructure.
Data Source
AI summary
One embodiment provides an apparatus for coupling a trunk network to a plurality of leaf passive optical networks (PONs). The apparatus includes one or more uplink ports for coupling to the trunk network, a plurality of downlink ports with a respective downlink port coupled to a leaf PON, and a switch chip for interconnecting the uplink ports and the downlink ports. The switch chip acts as a simple Ethernet switch with no traffic control ability.