Segment Routing Policy Stitching for Dynamic BSID Path Validation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Segment Routing (SR) protocols face challenges in verifying the explicit paths with Binding Segment Identifiers (BSIDs) for hierarchical SR policies, leading to error-prone configurations and lack of integrity checks, especially in networks without Path Computation Engines (PCE) or Border Gateway Protocol (BGP) deployments, and fail to adapt to dynamic changes in SR paths.
Innovation Solution
The proposed solution involves creating a stitched SR policy with dynamically updated Binding Segment Identifiers (BSIDs) using Interior Gateway Protocol (IGP) and Border Gateway Protocol (BGP) to ensure the SR policy is valid and operational, allowing nodes to adapt to changes in downstream domains and validate the integrity of hierarchical SR policies without manual configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If BSID segments are used as static labels in hierarchical SR policy, then configuration is simplified, but reliability and adaptability deteriorate due to error-prone manual configuration and inability to verify path integrity
Solution Approach 1:
The patent implements a feedback mechanism where the head-end node receives status information about remote SR policies through IGP advertisements from border nodes. This allows the head-end node to dynamically update its knowledge of downstream path status, enabling verification of hierarchical SR policy integrity without manual configuration while maintaining operational simplicity.
Solution Approach 2:
The patent introduces border nodes as intermediaries between upstream and downstream SR domains. These border nodes advertise remote BSID and status information to the head-end node through IGP, enabling path verification and dynamic adaptation without requiring direct control plane communication or complex manual configuration at the head-end node.
2Loss of information
If PCE with BGP or BGP-LS is deployed to obtain BSID information, then path computation capability is improved, but device complexity and deployment difficulty increase
Solution Approach 1:
The patent uses border nodes as intermediaries that naturally exist in multi-domain SR architectures. These border nodes advertise remote BSID information through standard IGP protocols, eliminating the need for additional PCE infrastructure or BGP-LS deployments while ensuring BSID information availability throughout the network.
Solution Approach 2:
The patent enables the network to self-configure and self-verify hierarchical SR policies using existing IGP protocols. Border nodes automatically advertise remote BSID and status information, and head-end nodes automatically update their policy information, eliminating the need for external PCE controllers or complex path computation infrastructure.
3Reliability
If per-policy BFD is implemented for LSP liveness detection, then reliability monitoring is improved, but scalability deteriorates due to scaling implications
Solution Approach 1:
The patent makes the border node's IGP advertisement mechanism serve multiple functions: it simultaneously distributes routing information and advertises remote BSID status for OAM purposes. This eliminates the need for separate per-policy BFD sessions while maintaining reliability monitoring capability, thereby improving scalability.
Solution Approach 2:
The patent merges the status advertisement function with the existing IGP routing information distribution mechanism. By combining BSID status information with regular IGP updates from border nodes, the system achieves scalable reliability monitoring without requiring additional protocol instances or increasing system complexity.
4Ease of manufacture
If static BSID labels are used in hierarchical SR policy, then configuration effort is reduced, but adaptability to dynamic changes deteriorates
Solution Approach 1:
The patent transforms the static BSID configuration model into a dynamic one by implementing automatic status information collection and policy updates. The head-end node continuously receives IGP advertisements from border nodes about remote SR policy status and automatically updates its hierarchical SR policies accordingly, enabling adaptation to dynamic changes without manual reconfiguration.
Solution Approach 2:
The patent establishes a feedback loop where the head-end node receives real-time status information about downstream SR policies through IGP advertisements and automatically adjusts its policy selection and forwarding behavior. This enables the system to adapt to dynamic changes in downstream domains while maintaining simple configuration at the head-end node.
Data Source
AI summary
Systems and methods for enhancing Segment Routing (SR) protocols are provided for enabling the stitching of a remote SR policy to a local SR policy. A method can include obtaining a Segment Routing (SR) policy for routing a packet along a path in a downstream domain, the SR policy including at least a destination field and a color field, the destination field defining an end-point of the path in the downstream domain, the end-point representing a destination node or service instance, the color field defining the path in the downstream domain, and storing the SR policy in the database.