Traffic Engineering Signal Degrade Avoidance
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Solution Overview
Problem
Current packet networking technologies lack a mechanism to account for signal degrade conditions when establishing or re-optimizing tunnels, leading to unpredictable traffic loss and inefficient path selection, particularly in protocols like MPLS-TE, BGP-LU, and Segment Routing.
Innovation Solution
Incorporating a Signal Degrade parameter as a Traffic Engineering attribute, which is advertised and monitored using OAM PDUs, and utilized in path computation through CSPF, allowing for the avoidance of links with signal degrade conditions during LSP establishment or re-optimization, and propagated using new TLVs in IS-IS, OSPF-TE, and BGP UPDATE messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional path selection protocols (MPLS-TE, BGP-LU, SR) are used without signal degrade awareness, then path computation is simple and fast, but traffic loss occurs on degraded links and network reliability deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-computing and storing signal degrade thresholds for each link in the Traffic Engineering Database before path computation occurs. Network elements monitor link conditions and update the TE database with signal degrade status in advance, so that when path computation is needed, the information is already available without adding computational complexity to the routing decision process itself
Solution Approach 2:
The patent introduces an intermediary mechanism - the Traffic Engineering Database - that acts as a mediator between link monitoring functions and path computation protocols. The TE database stores signal degrade information and makes it accessible to various routing protocols (MPLS-TE, BGP-LU, SR) without requiring each protocol to implement its own signal monitoring logic, thus maintaining protocol simplicity while improving reliability
2Adaptability or versatility
If LSP re-optimization is performed without signal degrade consideration, then tunnel adaptability improves, but traffic loss increases on degraded links
Solution Approach 1:
The patent applies dynamics by enabling LSP re-optimization to dynamically respond to changing link conditions. The system continuously monitors signal degrade status and automatically triggers LSP redial or path re-computation when degradation is detected, allowing tunnels to adapt to network conditions while avoiding degraded links. This dynamic behavior maintains tunnel adaptability without causing traffic loss on problematic links
Solution Approach 2:
The patent implements feedback mechanisms where link monitoring continuously measures signal quality and feeds this information back to the path computation function. When signal degrade conditions are detected, the feedback triggers LSP re-optimization to select alternative paths. This closed-loop feedback ensures tunnels adapt to degradation conditions while preventing traffic loss by redirecting before complete failure occurs
3Measurement precision
If signal degrade monitoring and propagation mechanisms are implemented, then path selection accuracy improves, but protocol complexity and overhead increase
Solution Approach 1:
The patent applies universality by designing a signal degrade monitoring and propagation mechanism that works across multiple routing protocols (MPLS-TE, BGP-LU, Segment Routing) through a common Traffic Engineering Database interface. The same monitoring infrastructure serves all protocol types, reducing overall system complexity while improving path selection accuracy for each protocol
Solution Approach 2:
The patent changes parameters by introducing signal degrade thresholds as additional path selection criteria in the TE database. Rather than fundamentally changing protocol operations, the solution adds a new parameter (signal degrade status) that path computation algorithms can consider alongside existing metrics like bandwidth and latency, improving accuracy while maintaining protocol compatibility
4Speed
If conventional LSP establishment proceeds without signal degrade awareness, then setup speed is fast, but service quality for sensitive traffic (voice, video) deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-populating the Traffic Engineering Database with signal degrade thresholds and link quality information before LSP establishment begins. Network elements perform signal monitoring and database updates in advance, so that when fast LSP setup is triggered, the path computation can immediately query accurate signal quality data without delaying the provisioning process
Solution Approach 2:
The patent substitutes traditional mechanical signal monitoring methods with an electronic database-driven approach. Instead of each LSP setup process individually probing link quality, the system replaces this with a centralized TE database that electronically stores and distributes signal degrade information, enabling fast setup while maintaining service quality awareness
Data Source
AI summary
A packet network includes a plurality of network elements interconnected to one another via a plurality of links, and systems and methods include, responsive to detecting a signal degrade condition on a link in the packet network, advertising the signal degrade condition on the link; maintaining a Traffic Engineering database which includes signal degrade condition status based on the advertising; and, responsive to path computation through the packet network, determining a best path considering the signal degrade condition status of the plurality of links. The systems and methods include further include, responsive to detecting the signal degrade condition on the link has cleared, advertising the signal degrade condition has cleared on the link.