EoMPLS

EoMPLS, or Ethernet over Multiprotocol Label Switching, is a technology that carries Ethernet frames over an MPLS network by establishing a pseudowire (PW) between two provider or customer edge devices. It provides a transparent layer 2 service that enables LAN-like connectivity across a service provider’s MPLS backbone, allowing geographically separated sites to appear as a single Ethernet segment to the end devices.

Encapsulation and operation: In EoMPLS, an Ethernet frame originating at a customer edge is encapsulated for transport within an MPLS packet. The MPLS label stack carries a PW label that identifies the pseudowire, and, in some deployments, an optional PW control word is added to assist sequencing and frame delineation. The core routers forward the encapsulated data using MPLS forwarding, while the edge devices decapsulate and deliver the Ethernet frame to the remote site.

Signaling and control: PW setup and maintenance are signaled using control-plane protocols such as LDP or RSVP-TE, according to standard pseudowire procedures. EoMPLS can support point-to-point connections and, with appropriate topology and signaling, multipoint or bridged services. The approach allows operators to run Ethernet services over an existing MPLS backbone without extending Layer 2 domains into the core.

Use cases and relationship to other technologies: EoMPLS is commonly used to provide WAN Ethernet services, including E-line (point-to-point) and, in some configurations, E-LAN-type functionality through associated control planes. It is a foundational technology for older L2 VPN deployments and a building block for more modern Ethernet VPN approaches. In contemporary networks, EVPN with MPLS has largely superseded traditional EoMPLS in new deployments, but EoMPLS remains in use for legacy networks and specific service requirements.