Non-Ingress Router TE LSP Path Reporting to PCE
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In large, multi-domain, multi-region, and multi-layer networks, constraint-based path computation is complex due to insufficient traffic engineering information exchange between administrative domains, limiting the visibility and optimization of Traffic Engineering Label Switched Paths (TE LSPs) for network routers.
Innovation Solution
Non-ingress routers report actual TE LSP paths to a Path Computation Element (PCE) through extended PCEP messages, enabling increased visibility and optimization by allowing any capable router along the path to report the TE LSP, rather than just the ingress LER, thereby facilitating improved path computation and reducing the number of concurrent PCEP sessions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If only ingress LER reports TE LSP paths to PCE, then PCEP session overhead is reduced, but visibility of TE LSPs in multi-domain networks is insufficient
Solution Approach 1:
The patent enables any router along the TE LSP path (not just ingress LER) to report path information to the PCE. This universal reporting capability allows multiple routers to perform the same reporting function, improving visibility across multi-domain networks while distributing the reporting load.
Solution Approach 2:
The patent segments the path reporting function from being centralized at the ingress LER only, and distributes it to multiple routers along the path. Each router can independently report the sub-path it observes, creating segmented reporting units that collectively provide complete path visibility.
2Productivity
If any capable router along the path reports TE LSP to PCE, then path computation optimization is improved, but number of concurrent PCEP sessions increases
Solution Approach 1:
The patent allows any capable router along the path to report TE LSP information, which is an excessive action compared to the traditional single ingress LER reporting. This partial participation model enables routers with sufficient capability to contribute path information without requiring all routers to participate, optimizing path computation while managing session overhead.
3Loss of information
If transit routers report actual TE LSP paths, then path visibility in multi-domain networks is enhanced, but information exchange complexity between administrative domains increases
Solution Approach 1:
The PCE acts as an intermediary that receives path information from multiple routers across different administrative domains. Instead of requiring direct information exchange between domains, the PCE centralizes the collection and processing of path information, simplifying cross-domain information exchange while enhancing overall path visibility.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Techniques are described for reporting, by non-ingress routers for traffic engineering label switched paths (TE LSPs) and to a path computation element, actual paths taken by the TE LSPs through the network. A first network device: receives, from a second network device, an LSP path signaling message that includes a route object having a first indication of at least a sub-path of a path for TE LSP through a network, wherein the first network device is not an ingress label edge router for the TE LSP; generates, in response to the LSP path signaling message and based at least in part on the route object, an LSP path report message that includes a second indication of the at least the sub-path of the path for the TE LSP; and sends, to a path computation element, the LSP path report message to notify the PCE.