Inter-domain TE-LSP Optimization via PCE Event Notifications
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Solution Overview
Problem
Current MPLS Traffic Engineering path computation techniques face challenges in optimizing inter-domain TE-LSPs due to limited network topology and resource information sharing across domain boundaries, leading to sub-optimal path selection and inefficient re-optimization triggers.
Innovation Solution
A novel inter-domain TE-LSP optimization technique that utilizes a Path Computation Element (PCE) in the event domain to detect events such as network restoration or increased bandwidth, notifying other PCEs and LSRs to trigger optimization requests, allowing for more optimal path computation across multiple domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If timer-based triggers are used for re-optimization, then re-optimization occurs periodically, but path quality remains sub-optimal due to delayed response to network events
Solution Approach 1:
The patent implements event-driven feedback mechanisms where PCEs notify other PCEs and LSRs about network events (restoration, bandwidth changes) that affect TE-LSP paths. This feedback loop enables immediate detection and response to topology changes, replacing periodic timer-based checks with event-triggered optimizations that maintain higher path quality without unnecessary delays
Solution Approach 2:
The system enables self-service optimization by allowing PCEs to autonomously detect events in their domains and automatically trigger re-optimization notifications to affected domains. This eliminates the need for external timer-based control, as each PCE independently monitors its domain and initiates optimization procedures when events occur, improving both responsiveness and path quality
2Reliability
If network topology information is shared across domain boundaries, then path computation becomes more optimal, but information security and domain autonomy are compromised
Solution Approach 1:
The patent introduces PCEs as intermediary entities that facilitate controlled information exchange between domains. Instead of direct topology information sharing, PCEs receive event notifications from local PCEs and forward relevant optimization triggers to remote PCEs without exposing detailed topology data. This intermediary mechanism enables optimal path computation through event awareness while maintaining domain information security and autonomy
Solution Approach 2:
The system extracts only the essential event information (restoration, bandwidth changes) needed for path optimization without sharing complete network topology information. By taking out only the critical event notifications rather than full topology data, domains can improve path computation quality while minimizing information exposure and security risks
3Speed
If event-driven notifications are implemented across domains, then re-optimization responsiveness improves, but network overhead and complexity increase
Solution Approach 1:
The patent segments the event notification system into domain-local PCEs that generate notifications and domain-remote PCEs that receive and act on them. This segmentation allows event-driven notifications to be implemented in a modular fashion, improving responsiveness through targeted notifications while reducing overall system complexity by limiting notification scope to affected domains rather than flooding all domains with all events
Data Source
AI summary
A technique triggers optimization of a traffic engineering (TE) label switched path (LSP) that spans multiple domains of a computer network from a head-end node of a local domain to a tail-end node of a remote domain. The technique is based on the detection of an event in the remote domain (“event domain”) that could create a more optimal TE-LSP, such as, e.g., restoration of a network element or increased available bandwidth. Specifically, a path computation element (PCE) in the event domain learns of the event and notifies other PCEs of the event through an event notification. These PCEs then flood an event notification to label switched routers (LSRs) in their respective domain. Upon receiving the notification, if an LSR has one or more TE-LSPs (or pending TE-LSPs), it responds to the PCE with an optimization request for the TE-LSPs. The PCE determines whether a particular TE-LSP may benefit from optimization based on the event domain (i.e., whether the TE-LSP uses the event domain), and processes the request accordingly.