Abstract
A mechanism is disclosed for qualifying Border Gateway Protocol (BGP) Route Target Constraint (RTC) membership advertisements with the virtual private network (VPN) service type or types to which the membership applies. An optional non-transitive BGP path attribute, referred to as the RT Service Scope attribute, carries a 32-bit field in which each bit position represents one VPN service type such as Layer 3 VPN (L3VPN), Ethernet VPN (EVPN), virtual private LAN service auto-discovery (VPLS-AD), multicast VPN (MVPN), or VPN flow specification. A route reflector (RR) or provider edge (PE) router that receives the attribute filters VPN route distribution toward that peer by both route target (RT) value and service type, rather than by RT value alone. Absence of the attribute is interpreted as all service types, which preserves the behavior specified in RFC 4684 for peers that do not implement the mechanism. A defined RR-to-RR aggregation behavior, with a default strip mode and an optional union mode, prevents per-PE scope information from propagating verbatim across the internal BGP (iBGP) mesh while preserving end-to-end filtering correctness. No BGP capability negotiation, RTC network layer reachability information (NLRI) format change, or coordinated software upgrade is required.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Anonymous, "Service-Scoped Route Target Constraint for Multi-Service BGP VPN Networks", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/11214