Unified HFC Network Management via OLT Switching and CMC Translation
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Solution Overview
Problem
Conventional hybrid fiber coaxial (HFC) networks are cost-ineffective when the number of subscribers is low, as they require expensive CMTS components for L3 and L2 switching, which are not feasible in all market scenarios.
Innovation Solution
The implementation of a small-sized Coaxial Media Converter (CMC) that performs only EoC MAC and PHY layers, eliminating the need for CMTS by shifting L3 and L2 switching capabilities to the OLT, allowing for simple mapping and translation at the CMC, and managing the CMC like an ONU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If CMTS components are used for L3 and L2 switching in HFC networks, then network management capability is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent extracts the L3 and L2 switching functions from the CMTS device and relocates them to the OLT. This separation allows the CMC to be a simple media converter without complex switching capabilities, while the OLT handles the sophisticated network management functions. The CMC only performs EoC MAC and PHY layer functions, dramatically reducing its complexity and cost.
Solution Approach 2:
The OLT acts as an intermediary between the CMC and the network management system. It receives management traffic intended for cable modems, translates it into appropriate formats, and forwards it through the CMC to the actual modems. This intermediary approach enables unified network management without requiring complex CMC devices.
2Adaptability or versatility
If CMTS components are deployed in HFC networks, then network control functionality is improved, but cost increases making it unfeasible for low-subscriber scenarios
Solution Approach 1:
The patent extracts the expensive CMTS functionality and relocates it to the OLT, which is a shared resource serving multiple PONs. This eliminates the need for individual CMTS devices at each HFC node, significantly reducing deployment costs especially in low-subscriber scenarios where a full CMTS would be underutilized.
Solution Approach 2:
The OLT serves multiple functions: it acts as the primary network terminal for PON, provides L3 and L2 switching capabilities, and functions as a network management controller for both fiber and coaxial subscribers. This multi-functionality consolidates what would otherwise require separate specialized devices, reducing overall system cost.
3Device complexity
If CMC size and complexity are reduced by eliminating CMTS, then cost and device simplicity are improved, but network management capability may be compromised
Solution Approach 1:
The OLT serves as an intermediary that compensates for the CMC's reduced capabilities. It performs the complex network management functions, translates management protocols between EPON and DOCSIS domains, and forwards management traffic appropriately. This allows the CMC to remain simple while network management capability is preserved at the OLT level.
Solution Approach 2:
The system creates a virtual representation of cable modems within the EPON domain by treating CMCs as ONUs. This allows the existing EPON OLT management interface to manage both fiber and coaxial subscribers uniformly, preserving network management capability without requiring the CMC itself to be complex.
Data Source
AI summary
Embodiments enable a network operator to use any (and a single) network management system (NMS) that it desires to manage a network having mixed fiber to the home optical network units (ONUs) and coaxial connected cable modems. For example, embodiments enable a cable company operator to use a DOCSIS (Data Over Cable Service Interface Specification) NMS (which the cable company already uses to manage its DOCSIS network) to manage such mixed network, by a simple addition of a DOCSIS Mediation Layer (DML) module between the NMS and the optical line terminal (OLT). On the other hand, embodiments enable a telephone company operator to use a standard EPON (Ethernet Passive Optical Network) OLT NMS with minor OLT and OAM (Operations, Administration, and Maintenance) protocol modifications to manage the same mixed network.