BESS Working Group H. Wang Internet-Draft D. Eastlake Intended status: Experimental Huawei Technologies Expires: April 25, 2019 October 22, 2018 EVPN ELAN use of Control Words draft-wang-bess-evpn-control-word-00 Abstract This document describes a method for negotiating and using EVPN control words for ELAN service. 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 April 25, 2019. 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 (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 Wang & Eastlake Expires April 25, 2019 [Page 1] Internet-Draft EVPN ELAN CWs October 2018 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. Control word Next-Hop Dependent Capability . . . . . . . . . 2 3. The Control Plane Process . . . . . . . . . . . . . . . . . . 3 4. The Data Plane Process . . . . . . . . . . . . . . . . . . . 3 5. Other Considerations . . . . . . . . . . . . . . . . . . . . 3 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 7. Security Considerations . . . . . . . . . . . . . . . . . . . 4 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 9. Normative References . . . . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction The usage of control words for Layer 2 services is described in RFC 7432 [RFC7432] and in some drafts on traditional VPLS but these documents do not explain how to deploy and negotiate control words. According to these documents, control words can only be used if all devices have control words enabled. If one of the devices does not have the control word enabled, that device cannot communicate with the other devices. RFC 8214 [RFC8214] defines the EVPN VPWS service and describes the negotiation process for the use of control words. However, the negotiation process described is only applicable to a P2P service such as VPWS, and is not applicable to an MP2MP service such as VPLS. This documents aims to define a control word negotiation and usage mechanism in an EVPN ELAN scenario. 2. Control word Next-Hop Dependent Capability The Control Word Next-Hop Capability has type code TBD and a length of 0 or 3 octet. The inclusion of the "Control word" Next-Hop Capability indicates that the BGP Next-Hop can be sent packets, for all routes indicated in the NRLI, with a control word added immediately after the label stack advertised with the NLRI. When the receiver receives a route that carries the capability, it can decide whether to add the control word to the packet according to its local capability. Wang & Eastlake Expires April 25, 2019 [Page 2] Internet-Draft EVPN ELAN CWs October 2018 3. The Control Plane Process The egress router needs to use the control word indicator label to determine whether there is a control word in the packet. There are two methods to specified the control word indicator label: The first method is to apply for a reserved label to indicate whether the packet contains a control word; The second method is to apply for a new label when the sending router advertises the control word capability, which is used to indicate whether the control word is included in the packet. When the value of the control word capability length is 0, it means we should use a reserved label as the control word indication label, which needs be assigned by IANA. If the value of the control word capability length is 3, the sending router must apply a new label to act as the control word indication label. Either of the above two methods can be used, and the first method is recommended. 4. The Data Plane Process The ingress router receives the routes with the control word capability attribute and, if the ingress router supports the control word capability and allows the control word capability to be carried when forwarding traffic to the egress router, a control word indicator label is added at the label stacks' bottom and then a 4-byte control word is added. If the ingress router does not support the control word capability or does not recognize the control word capability, the ingress router maintains the message consistent with the previous behavior when forwarding the packet to the egress router. When the egress router receives a packet from the MPLS network and finds a control word indication label in the packet, it means that the packet contains a control word, so the egress router does the control word process. 5. Other Considerations For the VXLAN and SRv6 networks, the current hash rule does not have the problem of Layer 2 services in the MPLS network. Therefore, no Wang & Eastlake Expires April 25, 2019 [Page 3] Internet-Draft EVPN ELAN CWs October 2018 support is required. If the attribute is received, it can be ignored. 6. IANA Considerations TBD 7. Security Considerations TBD 8. Acknowledgements TBD 9. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A., Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February 2015, . [RFC8214] Boutros, S., Sajassi, A., Salam, S., Drake, J., and J. Rabadan, "Virtual Private Wire Service Support in Ethernet VPN", RFC 8214, DOI 10.17487/RFC8214, August 2017, . Authors' Addresses Haibo (Rainsword) Wang Huawei Technologies Huawei Bld., No.156 Beiqing Road Beijing 100085 China Email: rainsword.wang@huawei.com Wang & Eastlake Expires April 25, 2019 [Page 4] Internet-Draft EVPN ELAN CWs October 2018 Donald Eastlake 3rd Huawei Technologies 1424 Pro Shop Court Davenport, FL 33896 USA Phone: +1-508-333-2270 Email: d3e3e3@gmail.com Wang & Eastlake Expires April 25, 2019 [Page 5]