Network Working Group D. Voyer, Ed. Internet-Draft C. Hassen Intended status: Standards Track K. Gillis Expires: December 31, 2018 Bell Canada C. Filsfils A. Venkateswaran Cisco Systems, Inc. June 29, 2018 SR Replication Policy for P2MP Service Delivery draft-voyer-spring-sr-p2mp-policy-00 Abstract This document describes the SR policy architecture for P2MP service delivery. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on December 31, 2018. Copyright Notice Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents Voyer, et al. Expires December 31, 2018 [Page 1] Internet-Draft P2MP SR Replication Policy June 2018 (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. SR Replication Policy . . . . . . . . . . . . . . . . . . . . 2 3. Spray SR Policy . . . . . . . . . . . . . . . . . . . . . . . 3 4. TreeSID - Controller Instantiated SR Tree . . . . . . . . . . 3 5. Illustration . . . . . . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 7. Security Considerations . . . . . . . . . . . . . . . . . . . 4 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 4 10. Normative References . . . . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction The document defines a variant of the SR Policy [I-D. ietf-spring- segment-routing-policy] which allows for replication for supporting point-to-multi-point service delivery. We call it an SR Replication Policy. We illustrate its use in two use-cases known as Spray and TreeSID. Spray uses an SR Replication Policy to replicate a packet, at a given node, along N SR paths to a set of leaf nodes. In the TreeSID use-case, a controller computes a tree from a root to a set of leaves and then programs each replication node of the tree with an SR Replication Policy. 2. SR Replication Policy This section is similar to section 2 of SR Policy draft [I-D.ietf-spring-segment-routing-policy] and holds information that applies equally to the Spray and TreeSID use-cases. The SR Replication policy is a variant of an SR policy [I-D.ietf-spring-segment-routing-policy], which provides packet replication. A SR Replication Policy is identified through the tuple . Voyer, et al. Expires December 31, 2018 [Page 2] Internet-Draft P2MP SR Replication Policy June 2018 A SR Replication may comprise of multiple candidate paths. A candidate path is valid when all its SID-Lists are valid. The active candidate path is selected based on the tiebreaking rules amongst the valid candidate-paths. Each SID-List is additionally identified by a endpoint where its SR path terminates. The endpoint could be the actual leaf of a P2MP service delivery tree or it could be the headend of another SR Replication Policy. Any traffic steered into a SR Replication Policy is replicated along the SID-Lists of its selected path towards the Leaf node. In the context of a SR Replication Policy, the selected path MAY have more than one SID-List. The weights of the SID-Lists is not applicable for a SR Replication Policy. They MUST be set to 1. Like any SR policy, a SR Replication Policy has a BSID [I-D.ietf-spring-segment-routing-policy] instantiated into the forwarding plane. A SR replication policy can be provisioned either locally or setup via controller. Traffic is steered into a SR Replication Policy in two ways o Based on a local policy-based routing at the Root node. o Based on remote classification and steering via the BSID of the SR Replication Policy. 3. Spray SR Policy This is a use-case of the SR Replication Policy in which packet replication occurs only at the Root node. A Spray SR Replication policy is instantiated only at the Root node. A packet, using this approach, is replicated directly to each Leaf node via a segment routed path from the Root to a given Leaf node. 4. TreeSID - Controller Instantiated SR Tree This is a use-case of the SR Replication policy in which packet replication occurs at the Root node and on some downstream branch points towards the Leaf node. Voyer, et al. Expires December 31, 2018 [Page 3] Internet-Draft P2MP SR Replication Policy June 2018 A SR Replication policy instantiated on the Root node takes a packet from the Root node to a set of branch points towards the Leaf node. A branch point MAY also be a Leaf node. Another SR Replication policy instantiated at each of these branch points take the packet down further to other branch points or Leaf nodes. 5. Illustration TBD 6. IANA Considerations This document makes no request of IANA. 7. Security Considerations There are no additional security risks introduced by this design. 8. Acknowledgements 9. Contributors 10. Normative References [I-D.ietf-spring-segment-routing-policy] Filsfils, C., Sivabalan, S., daniel.voyer@bell.ca, d., bogdanov@google.com, b., and P. Mattes, "Segment Routing Policy Architecture", draft-ietf-spring-segment-routing- policy-01 (work in progress), June 2018. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . Authors' Addresses Daniel Voyer (editor) Bell Canada Montreal CA Email: daniel.voyer@bell.ca Voyer, et al. Expires December 31, 2018 [Page 4] Internet-Draft P2MP SR Replication Policy June 2018 Clayton Hassen Bell Canada Vancouver CA Email: clayton.hassen@bell.ca Kurtis Gillis Bell Canada Halifax CA Email: kurtis.gillis@bell.ca Clarence Filsfils Cisco Systems, Inc. Brussels BE Email: cfilsfil@cisco.com Arvind Venkateswaran Cisco Systems, Inc. San Jose US Email: arvvenka@cisco.com Voyer, et al. Expires December 31, 2018 [Page 5]