PCE Selection via Predictive Response Time Advertisements

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Solution Overview

Problem

In computer networks, path computation across autonomous systems (AS) or areas is challenging due to limited visibility of network topology and resource information across boundaries, leading to sub-optimal PCE selection and increased path computation time, especially during network failures or re-optimization requests.

Innovation Solution

A technique for dynamically advertising PCE available path computation resources using predictive response time (PRT) notifications, allowing PCCs to select the most appropriate PCE based on resource availability, reducing congestion and overload by redirecting requests to less congested PCEs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If path computation requests are sent to PCEs without considering their current load and response time, then PCCs can simplify their selection process, but PCE overload occurs and path computation time increases

Engineering Contradiction:

Improvepath computation speedVSAvoidPCE response time delay

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

PCEs periodically advertise their predictive response time (PRT) to PCCs, creating a feedback mechanism that allows PCCs to monitor PCE load conditions and dynamically adjust their request routing decisions based on current PCE performance states

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

PCEs calculate and advertise their PRT values in advance before receiving path computation requests, allowing PCCs to proactively select the most appropriate PCE based on predicted performance rather than reacting after requests are submitted

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If PCCs randomly select PCEs for path computation requests, then PCE load distribution may be simplified, but sub-optimal PCE selection occurs and convergence time increases

Engineering Contradiction:

ImprovePCE selection simplicityVSAvoidpath computation reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The PCE selection process transitions from static random selection to dynamic selection based on advertised PRT values, allowing PCCs to adaptively choose PCEs with the best current performance characteristics while maintaining automated operation

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

PCCs use the advertised PRT parameter to make informed selection decisions, changing the selection criterion from random to based-on-performance-parameter, thereby improving reliability without significantly increasing operational complexity

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If PCEs process all path computation requests without load awareness, then request processing can be simplified, but PCE congestion increases and network responsiveness deteriorates

Engineering Contradiction:

ImprovePCE processing complexityVSAvoidnetwork convergence speed

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

PCEs autonomously monitor and advertise their own load conditions through PRT values, enabling PCCs to self-regulate request routing without requiring complex centralized load balancing mechanisms, thus maintaining simplicity while improving productivity

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9059867B2Technique for selecting a path computation element based on response time delay

Publication Date: 2015.06.16 CISCO TECHNOLOGY INC

AI summary

A technique efficiently selects a path computation element (PCE) to compute a path between nodes of a computer network. The PCE selection technique is illustratively based on dynamic advertisements of the PCE's available path computation resources, namely a predictive response time (PRT). To that end, the novel technique enables one or more PCEs to dynamically send (advertise) their available path computation resources to one or more path computation clients (PCCs). In addition, the technique enables the PCC to efficiently select a PCE (or set of PCEs) to service a path computation request based upon those available resources.