Inter-AS Repair Path Construction via Propagatable Addresses
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Solution Overview
Problem
Existing solutions for network repair in the event of inter-autonomous system (AS) link failures do not support repair mechanisms for indirect paths via multiple intermediate ASs, limiting the ability to minimize packet loss and ensure network connectivity.
Innovation Solution
An apparatus and method that assign a propagatable repair address for use in case of inter-AS connection failure, allowing the repair address to be propagated through data communications network components other than the failed connection, enabling the construction of a repair path using BGP routing protocol to bypass the failed link or node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing repair mechanisms are used for inter-AS link failures, then direct connections between ASs can be protected, but indirect paths via multiple intermediate ASs cannot be repaired
Solution Approach 1:
The patent segments the repair path into multiple hops through intermediate ASs rather than requiring a single direct connection. Each intermediate ASBR can independently participate in the repair path, allowing the solution to scale to complex multi-AS scenarios while maintaining reliability for both direct and indirect paths.
Solution Approach 2:
The patent introduces intermediate ASBRs as mediators that forward repair traffic between source and destination ASBRs when direct paths are unavailable. These intermediary nodes enable indirect repair paths through multiple ASs, expanding the versatility of the repair mechanism beyond direct connections.
2Reliability
If redundant direct connections are established between ASs for protection, then link failure repair is possible, but network complexity and cost increase
Solution Approach 1:
The patent performs preliminary actions by pre-establishing IGP routes and configuring ASBRs with repair capabilities before failures occur. When a failure happens, the pre-configured routes enable immediate repair traffic forwarding without requiring redundant physical connections, reducing network complexity while maintaining protection.
Solution Approach 2:
The patent creates a logical copy of the failed path using existing network infrastructure. Instead of building redundant physical connections, it replicates the repair function through software-based routing and tunneling over existing IGP routes, significantly reducing device complexity and cost.
3Adaptability or versatility
If IGP routes are used for repair traffic forwarding, then indirect paths through intermediate ASs are enabled, but packet loss may occur during path convergence
Solution Approach 1:
The patent performs preliminary actions by pre-calculating and installing repair routes using IGP before failures occur. When failures happen, traffic is immediately switched to pre-computed repair paths, eliminating convergence delays and packet loss that would otherwise occur during dynamic route calculation.
Solution Approach 2:
The patent maintains continuous packet forwarding capability by having repair routes pre-established and ready to activate immediately upon failure detection. The useful action of packet forwarding continues without interruption through the switch from primary to repair paths, avoiding the gap that occurs during traditional path convergence.
Data Source
AI summary
An apparatus and method as described for constructing a repair path for use in the event of failure of an inter-routing domain connection between respective components in first and second routing domains of a data communications network. The apparatus is arranged to assign a propagatable repair address for use in the event of failure of the inter-routing domain connection and to propagate the repair address via data communications network components other than the inter-routing domain connection.