What is ROV?

ROV (Route Origin Validation) is checking, against signed RPKI data, whether a BGP route's origin AS is authorised to announce that prefix.

Holders of address space publish Route Origin Authorizations (ROAs) in the RPKI, each saying that a given AS may originate a prefix up to a maximum length. Validators download and verify these, and pass the results, called Validated ROA Payloads (VRPs), to routers over the RTR protocol. For every route it receives, the router compares the prefix and the origin ASN (the last AS in the AS_PATH) against the VRPs, following RFC 6811, and gives the route one of three states:

• Valid: a VRP covers the prefix, the origin AS matches and the prefix is no longer than the maximum length;
• Invalid: at least one VRP covers the prefix, but none matches the origin or the length;
• NotFound: no VRP covers the prefix at all.

The widely recommended policy is to drop Invalid routes and accept the other two, since many prefixes still have no ROA.

ROV is very effective against the most common accidents: a network announcing someone else's prefix by mistake, or leaking more-specific routes. It cannot stop everything. An attacker can forge the origin by putting the right ASN at the end of a fake path, and a route leak that keeps the real origin passes as Valid; ASPA is aimed at that gap. Deployment is growing but not universal, so dropping Invalids only protects you and those behind you. A common self-inflicted problem is a ROA with too short a maximum length, which makes your own more-specific announcements Invalid. See RPKI, ROA and VRP. The RPKI and Route Origin Validation lesson runs ROV in a real FRR lab.