Network Working Group T. Eckert, Ed. Internet-Draft Huawei Intended status: Standards Track G. Cauchie Expires: January 9, 2020 Bouygues Telecom M. Menth University of Tuebingen July 8, 2019 Traffic Engineering for Bit Index Explicit Replication (BIER-TE) draft-ietf-bier-te-arch-03 Abstract This memo introduces per-packet stateless strict and loose path engineered replication and forwarding for Bit Index Explicit Replication packets ([RFC8279 ]). This is called BIER-TE. BIER-TE leverages the BIER architecture ([RFC8279 ]) and extends it with a new semantic for bits in the bitstring. BIER-TE can leverage BIER forwarding engines with little or no changes. In BIER, the BitPositions (BP) of the packets bitstring indicate BIER Forwarding Egress Routers (BFER), and hop-by-hop forwarding uses a Routing Underlay such as an IGP. In BIER-TE, BitPositions indicate adjacencies. The BIFT of each BFR are only populated with BPs that are adjacent to the BFR in the BIER- TE topology. The BIER-TE topology can consist of layer 2 or remote (route) adjacencies. The BFR then replicates and forwards BIER packets to those adjacencies. This results in the aforementioned strict and loose path forwarding. BIER-TE can co-exist with BIER forwarding in the same domain, for example by using seperate sub-domains. In the absence of routed adjacencies, BIER-TE does not require a BIER routing underlay, and can then be operated without requiring an IGP routing protocol. BIER-TE operates without explicit in-network tree-building and carries the multicast distribution tree in the packet header. It can therefore be a good fit to support multicast path steering in Segment Routing (SR) networks. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79 . Eckert, et al. Expires January 9, 2020 [Page 1] Internet-Draft BIER-TE ARCH July 2019