Forward Search Path Computation for Multi-Domain MPLS Networks
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Solution Overview
Problem
Current methods for computing point-to-point Label Switched Paths (LSPs) across multiple domains in MPLS networks, such as the Backward Recursive PCE-based Computation (BRPC) procedure, face challenges in determining the optimal path without relying on a specific sequence of domains and navigating complex domain meshes, leading to suboptimal results.
Innovation Solution
A system and method for Forward Search Path Computation (FSPC) that extends the Path Computation Element communication Protocol (PCEP), allowing PCEs to compute optimal paths across multiple domains independently of domain sequence and reducing complexity by using a candidate path list and result path list to select the minimum cost path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the Backward Recursive PCE-based Computation (BRPC) procedure is used to compute paths across multiple domains, then a path can be established, but the path may be suboptimal due to dependence on domain sequence and complexity in navigating domain meshes
Solution Approach 1:
The patent inverts the traditional backward recursive computation approach by implementing a forward search path computation method. Instead of starting from the destination and working backward through domains, the FSPC method starts from the source node and explores forward through the network, maintaining a candidate path list that is continuously updated. This inversion eliminates the need for predetermined domain sequences and allows the algorithm to naturally discover optimal paths by exploring all possible routes from the source.
Solution Approach 2:
The patent applies preliminary action by pre-initializing a candidate path list with the source node and systematically exploring all possible next-hop nodes before finalizing the complete path. The algorithm performs preliminary exploration of the network topology, building up candidate paths step by step through forward search, and only selects the final optimal path after all candidate paths have been evaluated. This preliminary exploration ensures optimality without requiring predetermined domain sequences.
2Productivity
If traditional path computation methods are used, then paths can be computed, but the complexity increases when dealing with mesh domains and multiple domains
Solution Approach 1:
The patent applies segmentation by dividing the path computation process into discrete steps corresponding to network hops. The forward search algorithm segments the exploration into phases, where each phase considers paths to the next-hop nodes from the current candidate paths. The candidate path list is segmented and updated at each step, maintaining only the most promising paths. This segmentation reduces complexity by breaking down the computationally intensive problem of finding optimal paths through mesh domains into manageable incremental steps.
3Ease of operation
If a predetermined domain sequence is required for path computation, then the computation process is simplified, but the path optimality cannot be guaranteed
Solution Approach 1:
The patent applies dynamics by making the path computation process adaptive rather than static. The forward search algorithm dynamically updates the candidate path list based on the explored network topology, automatically adjusting the search direction and candidate paths as new information becomes available during the forward exploration. This dynamic approach eliminates the need for predetermined domain sequences while maintaining computational simplicity, as the algorithm naturally adapts to the actual network structure and selects optimal paths based on real-time exploration results.
Data Source
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AI summary
Disclosed is an apparatus comprising a plurality of path computation elements (PCEs) associated with a plurality of inter-coupled domains and configured to communicate with a path computation client (PCC) associated with one of the domains and to implement a Forward Search Path Computation (FSPC) for a preferred path crossing the domains from a source node in a source domain of the plurality of inter-coupled domains to a destination node in a destination domain of the plurality of inter-coupled domains, wherein the preferred path is computed without using a determined order of the domains from the source domain to the destination domain.