VPWS service with EVPN mechanisms

Junos OS enables Ethernet VPN-virtual private wire service (EVPN-VPWS) to present a framework for delivering point-to-point EVC (E-Line) VPWS service with EVPN-signaling mechanisms. VPWS service with EVPN-signaling mechanisms enables single-active and all-active multihoming capabilities and support for inter-autonomous system (AS) options associated with BGP-signaled virtual private network service (VPNS).

The Metro Ethernet Forum (MEF) describes two models for E-Line service, Ethernet private line (EPL) and Ethernet virtual private line (EVPL). EPL provides a point-to-point Ethernet virtual connection (EVC) between a pair of dedicated user-to-network interfaces (UNIs), with transparency. EVPL differs from EPL in that it enables service multiplexing; that is, multiple EVCs per UNI.

Associating MEF definitions with EVPN terms, the services are defined as:

• EVPL - Service between Ethernet segment identifier (ESI) and VLAN pairs {ESI,VLAN}.
• EPL - Service between two ESIs. For this service, the circuit maps to a whole port; that is, all VLANs coming into a port are trunked together to the other endpoint of the service.

The EVPN-VPWS feature enables using an autodiscovery route per ESI and an autodiscovery route per Ethernet private instance (EVI) for E-Line service. There is no bridging for EVPN-VPWS service. Type 2 and Type 3 routes are not required. Type 4 routes are used for designated forwarder election, as they are for EVPN multipoint-to-multipoint EVC (E-LAN) services. However, designated forwarder election is useful only for single-active service. For all-active service, designated forwarder election is not required, because there is no broadcast, unknown unicast, and multicast (BUM) traffic in VPWS.