BGP ORF Aggregation Using Prefix-List Set Operations
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Solution Overview
Problem
Manual configuration of Outbound Route Filters (ORF) in Border Gateway Protocol (BGP) networks is cumbersome and prone to errors, leading to network outages and inefficiencies.
Innovation Solution
Automated ORF aggregation at BGP routers using circuitry to obtain and apply logical set operations on prefix-lists, generating sequence numbers for precedence in advertisements, and propagating aggregated ORF to downstream routers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual configuration of ORF filters is used, then network routing control can be implemented, but configuration complexity and error rate increase significantly
Solution Approach 1:
The system enables BGP routers to automatically generate, aggregate, and propagate ORF filters themselves without manual intervention. Routers autonomously perform logical set operations on prefix-lists, generate sequence numbers for precedence ordering, and propagate aggregated filters to downstream peers, making the system self-configuring and self-managing
Solution Approach 2:
The patent introduces a configuration parameter that can be added to the BGP protocol to enable or disable automated ORF aggregation for PERMIT/DENY actions. This parameter allows dynamic control of the aggregation behavior, transforming the system from static manual configuration to dynamic automated operation with adjustable control
2Reliability
If manual ORF propagation is performed across BGP networks, then routing policies can be enforced, but administrative overhead and time consumption increase
Solution Approach 1:
The system performs preliminary actions by automatically generating and aggregating ORF filters before they are needed for route advertisement. Routers pre-compute the aggregated filters using logical set operations on their prefix-lists and store them ready for propagation, eliminating the need for time-consuming manual configuration at the time of policy enforcement
Solution Approach 2:
BGP routers autonomously handle the entire ORF propagation process including obtaining prefix-lists from local and upstream routers, performing logical set operations to aggregate them, generating sequence numbers for proper ordering, and propagating the aggregated ORF to downstream routers without requiring network administrator intervention
3Reliability
If automated ORF aggregation is implemented, then configuration errors are reduced, but processing complexity at BGP routers increases
Solution Approach 1:
The patent segments the ORF aggregation process into distinct functional components: obtaining prefix-lists from multiple sources, performing logical set operations (union, intersection, difference) on PERMIT and DENY lists separately, generating sequence numbers for precedence ordering, and propagating the aggregated result. This segmentation makes the complex processing manageable and modular
Solution Approach 2:
The patent introduces an intermediary configuration parameter that mediates between manual and automated ORF aggregation modes. This parameter acts as a control mechanism that enables or disables the automated aggregation process, allowing the system to adapt to different operational requirements and reducing processing complexity when automation is not needed
4Reliability
If ORF filters are propagated without automated aggregation, then network traffic can be filtered, but invalid or missing configurations can cause network outages
Solution Approach 1:
The system provides beforehand cushioning by automatically validating and aggregating ORF filters before they are propagated across the network. The automated aggregation process ensures that filters are properly formed and consistent with the router's prefix-lists, preventing invalid or missing configurations from causing network outages. The system cushions against configuration errors by detecting and correcting them automatically
Solution Approach 2:
The patent implements feedback mechanisms where BGP routers monitor the propagation and application of aggregated ORF filters. The system receives feedback from the network operation and can adjust the aggregation process accordingly, ensuring that filters remain valid and effective. This feedback loop prevents configuration drift and maintains network availability by detecting and responding to potential issues
Data Source
AI summary
A Border Gateway Protocol (BGP) router is configured to obtain a plurality of prefix-lists one or more of (i) in local Outbound Route Filtering (ORF) and (ii) in ORF from upstream BGP routers, automatically apply logical set operations on the plurality of prefix-lists to determine an aggregated ORF for a downstream BGP router, and propagate the aggregated ORF to the downstream BGP router which uses the aggregated ORF for BGP advertisements. This can include auto generation of sequence numbers for the plurality of prefix-lists in the aggregated ORF, such that the downstream BGP router uses the sequence numbers for precedence in the advertisements. The prefix-lists can include one or more PERMIT lists, DENY lists, and a combination of PERMIT and DENY lists, with the logical set operations including union with the PERMIT lists, intersection with the DENY lists, and a combination of union, intersection, and set differences with the combination of PERMIT and DENY lists.