BGP AS Path Explorer

Inspect pasted candidate routes and replay a transparent, simplified best-path comparison without contacting routers or route collectors.

Candidate routes

Input format

Local ASN for loop detection

AS_SET path-length rule

Count confederation members in path length

Routes (maximum 2 MiB / 5,000 routes / 50,000 AS tokens)

JSON accepts an array or {"routes": [...]}. Fields: id, prefix, as_path, communities, large_communities, local_pref, med, origin, session, neighbor_id, weight.

Scope and limitations: this tool never performs BGP, RPKI, IRR, DNS, or network lookups. Private/reserved labels use fixed numeric ranges. AS_SET length treatment is disclosed and configurable. Real selection depends on vendor/version, policy, route validity, next-hop reachability, iBGP topology, IGP cost, route age, multipath, cluster/originator attributes, add-path, and state absent here.

Simplified decision sequence

Criteria in order (comma-separated)

Exclude paths containing the local ASN Compare MED only when remaining routes share neighboring ASN

Allowed criteria: weight (highest), local-pref (highest), as-length (lowest), origin (IGP < EGP < incomplete), MED (lowest), eBGP (preferred), neighbor-id (lowest IPv4). Any final tie is resolved by route ID only for deterministic display—not as a BGP rule.

Route report

Route	Prefix	AS path	Length	Attributes	Best?	Observations

Deterministic selection trace

Local AS-path graph

Each lane is one route; sets and confederation segments retain their delimiters. Preview is capped at 100 routes and 1,000 AS tokens.