BESS R. Srikanth Internet-Draft R. Satishkumar Intended status: Standards Track M. Perumal Expires: September 8, 2019 Ericsson March 7, 2019 BGP Extended Community for Virtual Private Wire Service Support in Ethernet VPN draft-ssm-bess-bgp-ec-evpn-vpws-00 Abstract This document describes an optional BGP extended community for use in Ethernet VPN (EVPN) Virtual Private Wire Service (VPWS). It helps in avoiding the situation where the EVPN VPWS instance is declared 'up' on one side but remains 'down' on the other side. 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 September 8, 2019. Copyright Notice Copyright (c) 2019 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 include Simplified BSD License text as described in Section 4.e of Srikanth, et al. Expires September 8, 2019 [Page 1] Internet-Draft draft-ssm-bess-bgp-ec-evpn-vpws-00 March 2019 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Problem Description . . . . . . . . . . . . . . . . . . . . . 3 4. Remote VPWS Instance Identifier Extended Community . . . . . 3 5. Usage of the Extended Community . . . . . . . . . . . . . . . 4 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 7. IANA Considerationss . . . . . . . . . . . . . . . . . . . . 5 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5 9. Normative References . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction In EVPN, a VPWS service instance is identified by a pair of per-EVI Ethernet A-D routes as described in [RFC8214]. Each Provider Edge (PE) node that wants to instantiate a VPWS service instance encodes the VPWS service instance identifier in the 32-bit Ethernet Tag ID field of the per-EVI Ethernet A-D route. The pair of PEs instantiating a VPWS service instance will each advertise a per-EVI Ethernet A-D route with its VPWS service instance identifier. Each PE is also configured with the other PE's VPWS service instance identifier. When each PE receives the other PE's per-EVI Ethernet A-D route with the VPWS service instance identifier of the other PE configured on each PE, the VPWS service instance is instantiated. However, if the VPWS service identifiers are misconfigured on either of the PEs, it can result in a situation where the EVPN VPWS service instance is declared 'up' on one PE but remains 'down' on the other PE. This document describes an optional BGP extended community for use in VPWS that can be used to avoid the above situation. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. Srikanth, et al. Expires September 8, 2019 [Page 2] Internet-Draft draft-ssm-bess-bgp-ec-evpn-vpws-00 March 2019 o EVPN: Ethernet VPN. o PE: Provider Edge Node. o VPWS: Virtual Private Wire Service defined in [RFC8214]. o LSI: Local VPWS service instance identifier. o RSI: Remote VPWS service instance identifier. o EC: Extended Community. 3. Problem Description Consider a case where PE1 and PE2 wants to instantiate a EVPN VPWS service instance with the following configurations: o PE1 is configured with Local VPWS service instance identifier (LSI) as 100 and Remote VPWS service instance identifier (RSI) as 200. o PE2 is configured with LSI as 300 and RSI as 100. With this setup: o PE1 will receive the per-EVI Ethernet A-D route from PE2 with Ethernet Tag ID as 300. o PE2 will receive the per-EVI Ethernet A-D route from PE1 with Ethernet Tag ID as 100. Though it is a misconfiguration, the EVPN VPWS service instance on PE2 will come up and PE2 will start forwarding traffic towards PE1. However, the EVPN VPWS service instance on PE1 will remain down. This may be undesirable (for example, it can resulting in wastage of network bandwidth). 4. Remote VPWS Instance Identifier Extended Community This document defines a new transitive extended community [RFC4360] to be included with per-EVI Ethernet A-D routes. This attribute is optional and can be used to avoid the situation described in Section 3. Srikanth, et al. Expires September 8, 2019 [Page 3] Internet-Draft draft-ssm-bess-bgp-ec-evpn-vpws-00 March 2019 +-------------------------------------------+ | Type (0x06) / Sub-type (TBD) (2 octets) | +-------------------------------------------+ | Remote Service ID (4 octets) | | | +-------------------------------------------+ Figure 1: EVPN VPWS Extended Community for remote service ID. Remote Service ID: This field MUST be set to the VPWS service instance identifier value of the remote PE (RSI). The VPWS service instance identifier value MAY be set to a 24-bit value, and when a 24-bit value is used, it MUST be right-aligned. 5. Usage of the Extended Community Consider the following setup: +------------+ +------------+ | PE1 | | PE2 | | (LSI: 100) |-------| (LSI: 200) | | (RSI: 200) | | (RSI: 100) | +------------+ +------------+ Figure 2: Network Topology for EVPN-VPWS EVPN-VPWS as described in [RFC8214] only exchange LSI value along with local label. In this case PE1 will send a per-EVI Ethernet A-D route with LSI 100 and PE2 will send a per-EVI Ethernet A-D route with LSI 200. With the extended community described in this document, PE1 sends the per-EVI Ethernet A-D route with LSI 100 and RSI 200 and PE2 sends the per-EVI Ethernet A-D route with LSI 200 and RSI 100. PE1 upon receiving the per-EVI Ethernet A-D route will bring up the EVPN VPWS service instance only if the LSI and RSI received in the route matches the LSI and RSI configured on PE1. Otherwise, PE1 keeps the EVPN VPWS service instance as down. 6. Security Considerations The security considerations described in RFC8214 apply to this document. Srikanth, et al. Expires September 8, 2019 [Page 4] Internet-Draft draft-ssm-bess-bgp-ec-evpn-vpws-00 March 2019 7. IANA Considerationss This document requests IANA to assign a new EVPN Extended Community of Type 0x06 and Sub-Type TBD: Sub-Type Value Name Reference --------------------------------------------------------------- TBD Remote VPWS Instance Identifier This document 8. Acknowledgments Thanks to Chundu Kotesh Babu and Jiang He for comments and suggestions. 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, . [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended Communities Attribute", RFC 4360, DOI 10.17487/RFC4360, February 2006, . [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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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 Srikanth Ramaswamy Ericsson Bangalore India Email: srikanth@ericsson.com Srikanth, et al. Expires September 8, 2019 [Page 5] Internet-Draft draft-ssm-bess-bgp-ec-evpn-vpws-00 March 2019 Satishkumar Rodd Ericsson Bangalore India Email: satishkumar.n.rodd@ericsson.com Muthu Arul Mozhi Perumal Ericsson Bangalore India Email: muthu.arul@gmail.com Srikanth, et al. Expires September 8, 2019 [Page 6]