DOCSIS Ring Protection Switch Recovery via Coordinated Ranging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In DOCSIS networks, ring protection switches cause service interruptions due to changes in signal delay and the need for modems to re-range and re-register, leading to increased recovery time after a network incident like a line break in a fiber ring.
Innovation Solution
Monitoring range delays for user devices and suspending bandwidth requests if a significant number of devices experience simultaneous shifts, indicating a ring protection switch, allowing for coordinated re-ranging and re-registration to minimize service disruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ring protection switch re-routes traffic over an intact portion, then signal transmission continuity is maintained, but signal delay changes causing modems to re-range and re-register
Solution Approach 1:
The CMTS performs preliminary detection of range delay changes before actual service disruption occurs. By monitoring range delay parameters and detecting changes that indicate a ring protection switch, the system can prepare for coordinated re-ranging operations, preventing the need for individual modem re-ranging and reducing overall recovery time.
Solution Approach 2:
The system implements feedback mechanisms where the CMTS continuously monitors range delay information from modems and detects changes indicating ring protection switch events. This feedback loop enables the CMTS to identify when coordinated re-ranging is needed and manage the recovery process efficiently, reducing service interruption time.
2Measurement precision
If modems undergo range and register process again after ring protection switch, then accurate distance measurement is restored, but service interruption occurs for users
Solution Approach 1:
The patent merges the range and register processes into a coordinated operation managed by the CMTS. Instead of modems independently re-ranging and re-registering (which causes service interruption), the CMTS coordinates these operations centrally, combining multiple modems' re-ranging into a single managed process that minimizes service disruption.
Solution Approach 2:
The CMTS acts as an intermediary that manages the re-ranging and re-registration process. Rather than modems directly undergoing these processes independently (causing service interruption), the CMTS mediates by coordinating the timing and execution of these operations, ensuring accurate distance measurement while minimizing service impact.
3Productivity
If modems continue to transmit using old range delay, then transmission continues without interruption, but collision interference occurs with other modems
Solution Approach 1:
The CMTS uses feedback from range delay monitoring to detect when modems are using outdated delay values. This feedback mechanism enables the CMTS to identify modems that need to update their range delay information, allowing the system to maintain transmission continuity while preventing collision interference through coordinated updates.
Data Source
AI summary
The range delay of each of a plurality of user devices of an HFC is monitored. If the delay of a number of devices shifts by about the same amount and at about the same time, then the number of devices having such a shift is compared to a predetermined threshold. If the number exceeds the threshold, it is assumed that a leg of a fiber ring in the HFC has been severed, and a ring switch is determined to have occurred.Upon this determination, granting of bandwidth requests to a group of user devices is suspended, and a ranging and register process for all devices in the group begins. The group may comprise all user devices affected by the broken fiber ring. Following ranging and registering, granting of bandwidth requests to the affected devices begins according to a normally-provisioned request grant schedule.