{"draft":"draft-ietf-bess-evpn-mh-split-horizon-11","doc_id":"RFC9746","title":"BGP EVPN Multihoming Extensions for Split-Horizon Filtering","authors":["J. Rabadan","K. Nagaraj","W. Lin","A. Sajassi"],"format":["HTML","TEXT","PDF","XML"],"page_count":"17","pub_status":"PROPOSED STANDARD","status":"PROPOSED STANDARD","source":"BGP Enabled ServiceS","abstract":"An Ethernet Virtual Private Network (EVPN) is commonly used with\r\nNetwork Virtualization Overlay (NVO) tunnels as well as with MPLS and\r\nSegment Routing (SR) tunnels. The multihoming procedures in EVPN may\r\nvary based on the type of tunnel used within the EVPN Broadcast\r\nDomain. Specifically, there are two multihoming split-horizon\r\nprocedures designed to prevent looped frames on multihomed Customer\r\nEdge (CE) devices: the Ethernet Segment Identifier (ESI) Label-based\r\nprocedure and the local-bias procedure. The ESI Label-based\r\nsplit-horizon procedure is applied to MPLS-based tunnels such as MPLS\r\nover UDP (MPLSoUDP), while the local-bias procedure is used for other\r\ntunnels such as Virtual eXtensible Local Area Network (VXLAN)\r\ntunnels.\r\n\r\nCurrent specifications do not allow operators to choose which\r\nsplit-horizon procedure to use for tunnel encapsulations that support\r\nboth methods. Examples of tunnels that may support both procedures\r\ninclude MPLSoUDP, MPLS over GRE (MPLSoGRE), Generic Network\r\nVirtualization Encapsulation (Geneve), and Segment Routing over IPv6\r\n(SRv6) tunnels. This document updates the EVPN multihoming procedures\r\ndescribed in RFCs 7432 and 8365, enabling operators to select the\r\nsplit-horizon procedure that meets their specific requirements.","pub_date":"March 2025","keywords":["EVPN Multihoming","Split Horizon Filtering","Local Bias","ESI","encapsulations","SHT"],"obsoletes":[],"obsoleted_by":[],"updates":["RFC7432","RFC8365"],"updated_by":[],"see_also":[],"doi":"10.17487\/RFC9746","errata_url":null}