evo-bgp-analysis

BGP Route Oscillation and Leak Analysis

This skill detects BGP route oscillation (preference dependency cycles) and route leaks (valley-free routing violations) in network topologies, then evaluates candidate solutions.

Key Concepts

Oscillation Detection

A preference dependency cycle exists when AS A prefers routes via AS B, and AS B prefers routes via AS A. This creates persistent route oscillation.

Route Leak Detection (Valley-Free)

Under the valley-free model:

• Customer-learned routes may be exported to any neighbor
• Peer-learned routes should only be exported to customers
• Provider-learned routes should only be exported to customers

A violation (leak) occurs when provider/peer-learned routes are exported to a provider or peer.

Solution Evaluation

• Oscillation fix: Must break the routing preference cycle in the topology
• Route leak fix: Must stop the leaking AS from advertising provider/peer routes to non-customer neighbors

Usage

import sys
sys.path.insert(0, '/app/environment/skills/evo-bgp-analysis/scripts')
from utils import run_analysis, validate_report

# Run end-to-end analysis
report = run_analysis('/app/data', '/app/output/oscillation_report.json')

# Validate the output
validate_report('/app/output/oscillation_report.json')

Scripts

scripts/utils.py

Core functions:

• load_json(path) - Load JSON file
• detect_oscillation(preferences) - Find preference dependency cycles
• detect_route_leaks(route_events, relationships) - Find valley-free violations
• evaluate_solution_oscillation(solution_text, preferences, topology) - Check if solution breaks cycle
• evaluate_solution_route_leak(solution_text, route_events, relationships) - Check if solution stops leak
• evaluate_all_solutions(solutions, preferences, topology, route_events, relationships) - Evaluate all solutions
• run_analysis(data_dir, output_path) - End-to-end entry point
• validate_report(output_path) - Validate output report structure and content