Network Working Group Z. Fu Internet-Draft T. Zhu Intended status: Standards Track H. Wang Expires: 9 September 2023 Huawei Technologies 8 March 2023 UMR application in Ethernet VPN(EVPN) draft-fu-bess-evpn-umr-application-00 Abstract This document describes an application scenario that how unknown MAC- route(UMR) is used in the EVPN network. In particular, this document describes how MAC address route and UMR route are advertised on DC's GW or NVE. This document also describes the soloution that MAC mobility issue due to the lack of advertisement of specific MAC routes. However, some incremental work is required, which will be covered in a separate document. 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 [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 9 September 2023. Copyright Notice Copyright (c) 2023 IETF Trust and the persons identified as the document authors. All rights reserved. Fu, et al. Expires 9 September 2023 [Page 1] Internet-Draft UMR application in Ethernet VPN(EVPN) March 2023 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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. The procedure of UMR . . . . . . . . . . . . . . . . . . . . 3 4. MAC Mobility for UMR . . . . . . . . . . . . . . . . . . . . 4 4.1. MAC Mobility Issue . . . . . . . . . . . . . . . . . . . 4 4.2. MAC Mobility Solution . . . . . . . . . . . . . . . . . . 4 5. E-tree for UMR . . . . . . . . . . . . . . . . . . . . . . . 5 6. IANA considerations . . . . . . . . . . . . . . . . . . . . . 6 7. Security Considerations . . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction In DCI scenario, if multiple DCs are interconnected into a single EVI, each DC will have to import all of the MAC addresses from each of the other DCs. [RFC9014]. In addition, in user authentication scenario, a large number of users send authentication packets to the aggregation device through the access device, as a result, there are large scale of MAC addresses on RRs and aggregation devices. This document describes the use of the Unknown MAC-route(UMR). The solution advertises an unknown MAC-route (UMR) route[RFC9014] instead of advertising all specific MAC routes and reducing the MAC scale. However, since the solution only sends UMR routes instead of advertising specific MAC routes, the MAC mobility function of EVPN cannot take effect normally. In particular, this document describes a MAC mobility procedure in UMR scenario. 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 BCP14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. "GW": Gateway or Data Center Gateway Fu, et al. Expires 9 September 2023 [Page 2] Internet-Draft UMR application in Ethernet VPN(EVPN) March 2023 "DC": Data Center "NVE": Network Virtualization Edge "UMR": Unknown MAC Route "I-ES and I-ESI": Interconnect Ethernet Segment and Interconnect Ethernet Segment Identifier. An I-ES is defined on the GWs for multihoming to/from the WAN. 3. The procedure of UMR +----------+ | | | GW | | | +----,-----+ / `. .' ', .` . / `, EVPN EVPN ,' `. / ', ` . ,' `, +------+ +---'--+ | | | | | NVE1| | NVE2| | | | | +------+ +------+ |---DC1---| |--DC2--| Figure 1 1. All the MAC addresses are learned on NVE1/NVE2 within DC should advertised to DC's GW device accrording EVPN MAC/IP routes in the control plane. 2. All the MAC addresses are learned on NVE within DC should advertised to the other NVE that in the same DC, so that the NVE to NVE that in the same DC communication is always direct and does not go through the GW[RFC7543]. 3. The MAC addresses are learned on NVE should not advertised to the other NVE that in the different DC. Fu, et al. Expires 9 September 2023 [Page 3] Internet-Draft UMR application in Ethernet VPN(EVPN) March 2023 4. The DC's GW advertise UMR route to NVE1/NVE2 instead of advertising the specific MAC in order to reduce the device's routes pressure. The UMR route is defined in[RFC7543] [RFC9014]and is a regular EVPN MAC/IP advertisement route in which the MAC address length is set to 48, the MAC address is set to 0, and the ESI field is set to DC's GW I-ES. 5. NVE1/NVE2 need to understand and process the UMR route, send frame to GW. Then GW will forward the packet to correct NVE. 4. MAC Mobility for UMR As shown above, since GW only sends UMR routes to NVE devices, NVE will not import the MAC addresses of NVEs in different DCs. When the MAC of DC1 migrates from NVE1 to DC2’s NVE2, NVE1 will not perceive this migration and keep learning the MAC that has migrated to NVE2. As a result, the frame traffic to MAC from GW may go to wrong site. 4.1. MAC Mobility Issue Step1: The user first goes online from NVE1, NVE1 learns the user's MAC1, and advertise EVPN MAC1 route to GW. Step2: The GW receives the MAC1 route from NVE1, installs MAC1 to the local MAC-VRF table which the next hop of MAC1 is NVE1. Since it only sends UMR routes to NVE, it will not send EVPN MAC1 route to NVE2. Step3: The user migrates to NVE2 and goes online. NVE2 learns the user's MAC1 and advertise EVPN MAC1 route to GW. Step4: The GW receives the MAC1 route from NVE2, which has the same prefix as the MAC1 route from NVE1, as a result, the GW will form load balancing MAC-VRF table. Step5: As a result, the frame traffic sent to MAC1 via the GW may be sent to NVE1 by mistake until MAC1 on NVE1 ages out. 4.2. MAC Mobility Solution In order to solve this mac migration issue, the GW SHOULD advertise the MAC route to the NVE when the GW detect the MAC has been migrated. There are two scenarios as follows. 1. One of the scenario: Fu, et al. Expires 9 September 2023 [Page 4] Internet-Draft UMR application in Ethernet VPN(EVPN) March 2023 Step1: When the GW receives MAC routes that have the same prefix, rather than different next hop and different ESI, the following conclusion can be drawn, which the MAC has been migrated. At the same time, the GW only send UMR route. Step2: If MAC route from NVE1 is selected as the best, the GW advertise MAC1 route to NVE2 with a MAC mobility extended community[RFC7432], that carrying the increased seq number. Step3: The NVE2 receives the MAC1 route with MAC mobility extended community, and will select the MAC1 from the GW as the best, and withdraw the MAC1 originally sent to the GW. Step4: The traffic from user will re-triggers NVE2 to learn the local MAC1, which resulting in migration, and the NVE2 will advertise MAC1 route with MAC mobility extended community that carrying the seq + 1. Step5: When the GW receives the MAC1 route with MAC mobility extended community that carrying seq + 1, the GW will select the MAC1 from NVE2 as best, and send MAC1 route with seq + 1 to NVE1. Step6: After receiving the MAC1 route with MAC mobility extended community that carrying seq + 1, the NVE1 will select the MAC1 from the GW as the best, and withdraw the MAC1 originally sent to the GW. 2. The other scenario: Step1: When the GW receives MAC routes that have the same prefix, rather than different next hop and different ESI, the following conclusion can be drawn, which the MAC has been migrated. At the same time, the GW only send UMR route. Step2: If MAC route from NVE2 is selected as the best, the GW advertise MAC1 route to NVE1 with a MAC mobility extended community, that carrying the increased seq number. Step3: After receiving the MAC1 route with MAC mobility extended community that carrying seq + 1, the NVE1 will select the MAC1 from the GW as the best, and withdraw the MAC1 originally sent to the GW. 5. E-tree for UMR In addition, the draft also consider to the E-tree function in the UMR solution. The procedures would be detailed in a future revision. Fu, et al. Expires 9 September 2023 [Page 5] Internet-Draft UMR application in Ethernet VPN(EVPN) March 2023 6. IANA considerations TBD 7. Security Considerations TBD 8. References [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, . [RFC7543] Jeng, H., Jalil, L., Bonica, R., Patel, K., and L. Yong, "Covering Prefixes Outbound Route Filter for BGP-4", RFC 7543, DOI 10.17487/RFC7543, May 2015, . [RFC9014] Rabadan, J., Ed., Sathappan, S., Henderickx, W., Sajassi, A., and J. Drake, "Interconnect Solution for Ethernet VPN (EVPN) Overlay Networks", RFC 9014, DOI 10.17487/RFC9014, May 2021, . Authors' Addresses Zheng Fu Huawei Technologies No.101 Software Avenue, Yuhuatai District Nanjing 210012 China Email: fuzheng7@huawei.com Tong Zhu Huawei Technologies No.101 Software Avenue, Yuhuatai District. Nanjing 210012 China Email: zhu.tong@huawei.com Haibo Wang Huawei Technologies Huawei Bld., No.156 Beiqing Rd. Fu, et al. Expires 9 September 2023 [Page 6] Internet-Draft UMR application in Ethernet VPN(EVPN) March 2023 Beijing 100095 China Email: rainsword.wang@huawei.com Fu, et al. Expires 9 September 2023 [Page 7]