Network Working Group A. Sajassi, Ed. Internet-Draft G. Badoni Intended status: Standards Track P. Warade Expires: December 10, 2021 S. Pasupula Cisco Systems J. Drake, Ed. Juniper J. Rabadan, Ed. Nokia June 8, 2021 EVPN Support for L3 Fast Convergence and Aliasing/Backup Path draft-sajassi-bess-evpn-ip-aliasing-02 Abstract This document proposes an EVPN extension to allow several of its multihoming functions, fast convergence and aliasing/backup path, to be used in conjunction with inter-subnet forwarding. 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 10, 2021. Copyright Notice Copyright (c) 2021 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 Sajassi, et al. Expires December 10, 2021 [Page 1] Internet-Draft IP Aliasing Support for EVPN June 2021 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 1.1. Ethernet Segments for Host Routes in Symmetric IRB . . . 3 1.2. Inter-subnet Forwarding for Prefix Routes in the Interface-less IP-VRF-to-IP-VRF Model . . . . . . . . . . 4 1.3. Ethernet Segments for Prefix routes in IP-VRF-to-IP-VRF use-cases . . . . . . . . . . . . . . . . . . . . . . . . 4 1.4. Terminology and Conventions . . . . . . . . . . . . . . . 5 2. IP Aliasing and Backup Path . . . . . . . . . . . . . . . . . 6 2.1. Constructing the IP A-D per EVI Route . . . . . . . . . . 7 3. Fast Convergence for Routed Traffic . . . . . . . . . . . . . 8 3.1. Constructing IP A-D per Ethernet Segment Route . . . . . 9 3.1.1. IP A-D per ES Route Targets . . . . . . . . . . . . . 9 3.2. Avoiding convergence issues by synchronizing IP prefixes 9 3.3. Handling Silent Host MAC/IP route for IP Aliasing . . . . 9 3.4. MAC Aging . . . . . . . . . . . . . . . . . . . . . . . . 10 4. Determining Reachability to Unicast IP Addresses . . . . . . 10 4.1. Local Learning . . . . . . . . . . . . . . . . . . . . . 10 4.2. Remote Learning . . . . . . . . . . . . . . . . . . . . . 11 4.3. Constructing the IP Routes . . . . . . . . . . . . . . . 11 4.3.1. Route Resolution . . . . . . . . . . . . . . . . . . 11 5. Forwarding Unicast Packets . . . . . . . . . . . . . . . . . 11 6. Load Balancing of Unicast Packets . . . . . . . . . . . . . . 12 7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 12 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 11.1. Normative References . . . . . . . . . . . . . . . . . . 12 11.2. Informative References . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 1. Introduction This document proposes an EVPN extension to allow several of its multihoming functions, fast convergence and aliasing/backup path, to be used in conjunction with inter-subnet forwarding. It re-uses the existing EVPN routes, the Ethernet A-D per ES and the Ethernet A-D per EVI routes, which are used for these multihoming functions. In particular, there are three use-cases that could benefit from the use of these multihoming functions: Sajassi, et al. Expires December 10, 2021 [Page 2] Internet-Draft IP Aliasing Support for EVPN June 2021 a. Inter-subnet forwarding for host routes in symmetric IRB [I-D.ietf-bess-evpn-inter-subnet-forwarding]. b. Inter-subnet forwarding for prefix routes in the interface-less IP-VRF-to-IP-VRF model [I-D.ietf-bess-evpn-prefix-advertisement]. c. Inter-subnet forwarding for prefix routes when the ESI is used exclusively as an L3 construct [I-D.ietf-bess-evpn-prefix-advertisement]. 1.1. Ethernet Segments for Host Routes in Symmetric IRB Consider a pair of multi-homing PEs, PE1 and PE2, as illustrated in Figure 1. Let there be a host H1 attached to them. Consider PE3 and a host H3 attached to it. +----------------+ | EVPN | +------+ | | PE1 | +---> | +------+ | RT2 | | | | IP1 +--+---+ +---+ | ES1 +------+ ESI1 | PE3 | H1+--+CE1+--+ | | +-+H3 +---+ | +------+ | | | | PE2 | +--+---+ +------+ | | | | | +------+ | | | +----------------+ Figure 1: Inter-subnet traffic between Multihoming PEs and Remote PE With Asymmetric IRB [I-D.ietf-bess-evpn-inter-subnet-forwarding], if H3 sends inter-subnet traffic to H1, routing will happen at PE3. PE3 will be attached to the destination IRB interface and will trigger ARP/ND requests if it does not have an ARP/ND adjacency to H1. A subsequent routing lookup will resolve the destination MAC to H1's MAC address. Furthermore, H1's MAC will point to an ECMP EVPN destination on PE1 and PE2, either due to host route advertisement from both PE1 and PE2, or due to Ethernet Segment MAC Aliasing as detailed in [RFC7432]. With Symmetric IRB [I-D.ietf-bess-evpn-inter-subnet-forwarding], if H3 sends inter-subnet traffic to H1, a routing lookup will happen at Sajassi, et al. Expires December 10, 2021 [Page 3] Internet-Draft IP Aliasing Support for EVPN June 2021 PE3's IP-VRF and this routing lookup will not yield the destination IRB interface and therefore MAC Aliasing is not possible. In order to have per-flow load balancing for H3's routed traffic to H1, an IP ECMP list (to PE1/PE2) needs to be associated to H1's host route in the IP-VRF route-table. If H1 is locally learned only at one of the multi-homing PEs, PE1 or PE2, due to LAG hashing, PE3 will not be able to build an IP ECMP list for the H1 host route. With the extension described in this document, PE3's IP-VRF becomes Ethernet-Segment-aware and builds an IP ECMP list for H1 based on the advertisement of ES1 along with H1 in a MAC/IP route and the availability of ES1 on PE1 and PE2. 1.2. Inter-subnet Forwarding for Prefix Routes in the Interface-less IP-VRF-to-IP-VRF Model In this model there is no Overlay Index and hence no recursive resolution of the IP Prefix route to either a MAC/IP Advertisement or an Ethernet A-D per ES/EVI route, which means that the fast convergence and aliasing/backup path functions are disabled. In a sense it is already described in section 4.3 of [I-D.ietf-bess-evpn-prefix-advertisement], Bump-in-the-Wire Use-Case, but that section does not describe aliasing. I.e., this document can be considered to be adding the aliasing/backup path function to the Bump-in-the-Wire Use-Case. 1.3. Ethernet Segments for Prefix routes in IP-VRF-to-IP-VRF use-cases This document also enables fast convergence and aliasing/backup path to be used even when the ESI is used exclusively as an L3 construct. As an example, consider the scenario in Figure 2 in which PE1 and PE2 are multi-homed to CE1. However, and contrary to CE1 in Figure 1, in this case the links between CE1 and PE1/PE2 are used exclusively for L3 protocols and L3 forwarding in different BDs, and a BGP session established between CE1's loopback address and PE1's IRB address. In these use-cases, sometimes the CE supports a single BGP session to one of the PEs (through which it advertises a number of IP Prefixes seating behind itself) and yet, it is desired that remote PEs can build an IP ECMP list or backup IP list including all the PEs multi- homed to the same CE. For example, in Figure 2, CE1 has a single eBGP neighbor, i.e., PE1. Load-balancing for traffic from CE1 to H4 can be accomplished by a default route with next-hops PE1 and PE2, however, load-balancing from H4 to any of the prefixes attached to CE1 would not be possible since only PE1 would advertise EVPN IP Prefix routes for CE1's prefixes. This document provides a solution so that PE3 considers PE2 as a next-hop in the IP ECMP list for CE1's Sajassi, et al. Expires December 10, 2021 [Page 4] Internet-Draft IP Aliasing Support for EVPN June 2021 prefixes, even if PE2 did not advertise the IP Prefix routes for those prefixes in the first place. +-----------------------+ | EVPN | PE1 | | +-------------------+ | | IRB1 | | | +---+ +------+ | -------> | +-----------|BD1|---|IPVRF1| | RT5 | eBGP | | +---+ | | | 50.0/24 | PE3 +------------------------>10.1 +------+ | ESI1 +----------------+ | | +-------------------+ | +------+ | +-----+10.2 | | ^ | |IPVRF1| +---+ | | CE1 |-----+ ES1 | | | | |-|BD3|---H4 | |-----+ | +--------| +------+ +---+ | +-----+20.2 | PE2 | +---| | lo1 | +--------------+----+ | +----------------+ 1.1.1.1 | | IRB2 | | | Prefixes: | | +---+ +------+ | | | 50.0/24 +-----------|BD2|---|IPVRF1| |<--+ | 60.0/24 | +---+ | | | | | 20.1 +------+ | | +-------------------+ | | | +-----------------------+ Figure 2: Layer-3 Multihoming PEs 1.4. Terminology and Conventions 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. - IRB: Integrated Routing and Bridging - IRB Interface: Integrated Bridging and Routing Interface. A virtual interface that connects the Bridge Table and the IP-VRF on an NVE. - BD: Broadcast Domain. An EVI may be comprised of one BD (VLAN- based or VLAN Bundle services) or multiple BDs (VLAN-aware Bundle services). - Bridge Table: An instantiation of a broadcast domain on a MAC-VRF. Sajassi, et al. Expires December 10, 2021 [Page 5] Internet-Draft IP Aliasing Support for EVPN June 2021 - CE: Customer Edge device, e.g., a host, router, or switch.s - EVI: An EVPN instance spanning the Provider Edge (PE) devices participating in that EVPN. - MAC-VRF: A Virtual Routing and Forwarding table for Media Access Control (MAC) addresses on a PE. - Ethernet Segment (ES): When a customer site (device or network) is connected to one or more PEs via a set of Ethernet links, then that set of links is referred to as an 'Ethernet segment'. - Ethernet Segment Identifier (ESI): A unique non-zero identifier that identifies an Ethernet segment is called an 'Ethernet Segment Identifier'. - IP-VRF: A VPN Routing and Forwarding table for IP routes on an NVE/PE. The IP routes could be populated by any routing protocol, E.g., EVPN, IP-VPN and BGP PE-CE IP address families. An IP-VRF is also an instantiation of a layer 3 VPN in an NVE/PE. - IP route: An IP Prefix route or a MAC/IP Advertisement route that contains a host route. - LACP: Link Aggregation Control Protocol. - PE: Provider Edge device. - Single-Active Redundancy Mode: When only a single PE, among all the PEs attached to an Ethernet segment, is allowed to forward traffic to/from that Ethernet segment for a given VLAN, then the Ethernet segment is defined to be operating in Single-Active redundancy mode. - All-Active Redundancy Mode: When all PEs attached to an Ethernet segment are allowed to forward known unicast traffic to/from that Ethernet segment for a given VLAN, then the Ethernet segment is defined to be operating in All-Active redundancy mode. - RT5: EVPN IP Prefix route, as specified in [I-D.ietf-bess-evpn-prefix-advertisement]. 2. IP Aliasing and Backup Path In order to address the use-cases described in Section 1, above, this document proposes that: Sajassi, et al. Expires December 10, 2021 [Page 6] Internet-Draft IP Aliasing Support for EVPN June 2021 1. A PE that is attached to a given ES will advertise a set of one or more Ethernet A-D per ES routes for that ES. Each is termed an 'IP A-D per ES' route and is tagged with the route targets (RTs) for one or more of the IP-VRFs defined on it for that ES; the complete set of IP A-D per ES routes contains the RTs for all of the IP-VRFs defined on it for that ES. A remote PE imports an IP A-D per ES route into the IP-VRFs corresponding to the RTs with which the route is tagged. When the complete set of IP A-D per ES routes has been processed, a remote PE will have imported an IP A-D per ES route into each of the IP-VRFs defined on it for that ES; this enables fast convergence for each of these IP-VRFs. 2. A PE advertises for this ES, an Ethernet A-D Per EVI route for each of the IP-VRFs defined on it. Each is termed an 'IP A-D per EVI' route and is tagged with the RT for a given IP-VRF. A remote PE imports an IP A-D per EVI route into the IP-VRF corresponding to the RT with which the route is tagged. The label contained in the route enables aliasing/backup path for the routes in that IP-VRF. To address the third use-case described in Section 1, where the links between a CE and its multihomed PEs are used exclusively for L3 protocols and L3 forwarding, a PE uses the procedures described in 1) and 2), above. The ESI is of type 4 [RFC7432] and set to the router ID of the CE. The processing of the IP A-D per ES and the IP A-D per EVI routes is as defined in [RFC7432] and [RFC8365] except that the fast convergence and aliasing/backup path functions apply to the routes contained in an IP-VRF. In particular, a remote PE that receives an IP route with a non-reserved ESI and the RT of a particular IP-VRF SHOULD consider it reachable by every PE that has advertised an IP A-D per ES and IP A-D per EVI route for that ESI and IP-VRF. 2.1. Constructing the IP A-D per EVI Route The construction of the IP A-D per EVI route is the same as that of the Ethernet A-D per EVI route, as described in [RFC7432], with the following exceptions: - The Route-Distinguisher is for the corresponding IP-VRF. - The Ethernet Tag should be set to 0. - The route SHOULD carry the RT of the corresponding IP-VRF. Sajassi, et al. Expires December 10, 2021 [Page 7] Internet-Draft IP Aliasing Support for EVPN June 2021 - The route MUST carry the PE's MAC Extended Community if the encapsulation used between the PEs for inter-subnet forwarding is an Ethernet NVO tunnel [I-D.ietf-bess-evpn-prefix-advertisement]. - The route SHOULD carry the Layer 2 Extended Community [RFC8214]. For all-active multihoming, all PEs attached to the specified ES will advertise P=1. For backup path, the Primary PE will advertise P=1 and the Backup PE will advertise P=0, B=1. o The Primary PE SHOULD be a PE with a routing adjacency to the attached CE. o The Primary PE MAY be determined by policy or MAY be elected by a DF Election as in [RFC8584]. 3. Fast Convergence for Routed Traffic Host or Prefix reachability is learned via the BGP-EVPN control plane over the MPLS/NVO network. IP routes for a given ES are advertised by one or more of the PEs attached to that ES. When one of these PEs fails, a remote PE needs to quickly invalidate the IP routes received from it. To accomplish this, EVPN defined the fast convergence function specified in [RFC7432]. This document extends fast convergence to inter-subnet forwarding by having each PE advertise a set of one or more IP A-D per ES routes for each locally attached Ethernet segment (refer to Section 3.1 below for details on how these routes are constructed). A PE may need to advertise more than one IP A-D per ES route for a given ES because the ES may be in a multiplicity of IP- VRFs and the Route-Targets for all of these IP-VRFs may not fit into a single route. Advertising a set of IP A-D per ES routes for the ES allows each route to contain a subset of the complete set of Route Targets. Each IP A-D per ES route is differentiated from the other routes in the set by a different Route Distinguisher (RD). Upon failure in connectivity to the attached ES, the PE withdraws the corresponding set of IP A-D per ES routes. This triggers all PEs that receive the withdrawal to update their next-hop adjacencies for all IP addresses associated with the Ethernet Segment in question, across IP-VRFs. If no other PE has advertised an IP A-D per ES route for the same Ethernet Segment, then the PE that received the withdrawal simply invalidates the IP entries for that segment. Otherwise, the PE updates its next-hop adjacencies accordingly. These routes should be processed with higher priority than IP route withdrawals upon failure. Similar priority processing is needed even on the intermediate Route Reflectors. Sajassi, et al. Expires December 10, 2021 [Page 8] Internet-Draft IP Aliasing Support for EVPN June 2021 3.1. Constructing IP A-D per Ethernet Segment Route This section describes the procedures used to construct the IP A-D per ES route, which is used for fast convergence (as discussed in Section 3). The usage/construction of this route remains similar to that described in section 8.2.1. of [RFC7432] with a few notable exceptions as explained in following sections. 3.1.1. IP A-D per ES Route Targets Each IP A-D per ES route MUST carry one or more Route Targets (RTs). The set of IP A-D per ES routes MUST carry the entire set of IP-VRF RTs for all the IP-VRFs defined on that ES. 3.2. Avoiding convergence issues by synchronizing IP prefixes Consider a pair of multi-homing PEs, PE1 and PE2. Let there be a host H1 attached to them. Consider PE3 and a host H3 attached to it. If the host H1 is learned on both the PEs, the ECMP path list is formed on PE3 pointing to (PE1/PE2). Traffic from H3 to H1 is not impacted even if one of the PEs fails as the path list gets corrected upon receiving the withdrawal of the fast convergence route(s) (IP AD per ES routes). In a case where H1 is locally learned only on PE1 due to LAG hashing or a single routing protocol adjacency to PE1, at PE3, H1 has ECMP path list (PE1/PE2) using Aliasing as described in this document. Traffic from H3 can reach H1 via either PE1 or PE2. PE2 should install local forwarding state for IP routes advertised by other PEs attached to the same ES (i.e., PE1) but not advertise them as local routes. When the traffic from H3 reaches PE2, PE2 will be able forward the traffic to H1 without any convergence delay (caused by triggering ARP/ND to H1 or to the next-hop to reach H1). The synchronization of the IP routes across all PEs of the same Ethernet Segment is important to solve convergence issues. 3.3. Handling Silent Host MAC/IP route for IP Aliasing Consider the example of Figure 1 for IP aliasing. If PE1 fails, PE3 will receive the withdrawal of the fast convergence route(s) and update the ECMP list for H1 to be just PE2. When the IP route for H1 is also withdrawn, neither PE2 nor PE3 will have a route to H1, and traffic from H3 to H1 is blackholed until PE2 learns H1 and advertises an IP route for it. Sajassi, et al. Expires December 10, 2021 [Page 9] Internet-Draft IP Aliasing Support for EVPN June 2021 This blackholing can be much worse if the H1 behaves like a silent host. IP address of H1 will not be re-learned on PE2 till H1 ARP/ND messages or some traffic triggers ARP/ND for H1. PE2 can detect the failure of PE1's reachability in different ways: a. When PE1 fails, the next hop tracking to PE1 in the underlay routing protocols can help detect the failure. b. Upon the failure of its link to CE1, PE1 will withdraw its IP A-D route(s) and PE2 can use this as a trigger to detect failure. Thus to avoid blackholing, when PE2 detects loss of reachability to PE1, it should trigger ARP/ND requests for all remote IP prefixes received from PE1 across all affected IP-VRFs. This will force host H1 to reply to the solicited ARP/ND messages from PE2 and refresh both MAC and IP for the corresponding host in its tables. Even in core failure scenario on PE1, PE1 must withdraw all its local layer-2 connectivity, as Layer-2 traffic should not be received by PE1. So when ARP/ND is triggered from PE2 the replies from host H1 can only be received by PE2. Thus H1 will be learned as local route and also advertised from PE2. It is recommended to have a staggered or delayed deletion of the IP routes from PE1, so that ARP/ND refresh can happen on PE2 before the deletion. 3.4. MAC Aging In the same example as in Section 3.3, PE1 would do ARP/ND refresh for H1 before it ages out. During this process, H1 can age out genuinely or due to the ARP/ND reply landing on PE2. PE1 must withdraw the local entry from BGP when H1 entry ages out. PE1 deletes the entry from the local forwarding only when there are no remote synced entries. 4. Determining Reachability to Unicast IP Addresses 4.1. Local Learning The procedures for local learning do not change from [RFC7432] or [I-D.ietf-bess-evpn-prefix-advertisement]. Sajassi, et al. Expires December 10, 2021 [Page 10] Internet-Draft IP Aliasing Support for EVPN June 2021 4.2. Remote Learning The procedures for remote learning do not change from [RFC7432] or [I-D.ietf-bess-evpn-prefix-advertisement]. 4.3. Constructing the IP Routes The procedures for constructing MAC/IP Address or IP Prefix Advertisements do not change from [RFC7432] or [I-D.ietf-bess-evpn-prefix-advertisement]. 4.3.1. Route Resolution If the ESI field is set to reserved values of 0 or MAX-ESI, the IP route resolution MUST be based on the IP route alone. If the ESI field is set to a non-reserved ESI, the IP route resolution MUST happen only when both the IP route and the associated set of IP A-D per ES routes have been received. To illustrate this with an example, consider a pair of multi-homed PEs, PE1 and PE2, connected to an all-active Ethernet Segment. A given host with IP address H1 is learned by PE1 but not by PE2. When the IP route from PE1 and a set of IP A-D per ES and IP A-D per EVI routes from PE1 and PE2 are received, then (1) PE3 can forward traffic destined to H1 to both PE1 and PE2. If after (1) PE1 withdraws the IP A-D per ES route, then PE3 will forward the traffic to PE2 only. If after (1) PE2 withdraws the IP A-D per ES route, then PE3 will forward the traffic to PE1 only. If after (1) PE1 withdraws the IP route, then PE3 will do delayed deletion of H1, as described in Section 3.3. If after (1) PE2 advertised the IP route, but PE1 withdraws it, PE3 will continue forwarding to both PE1 and PE2 as long as it has the IP A-D per ES and the IP A-D per EVI route from both. 5. Forwarding Unicast Packets Refer to Section 5 in [I-D.ietf-bess-evpn-inter-subnet-forwarding] and [I-D.ietf-bess-evpn-prefix-advertisement]. Sajassi, et al. Expires December 10, 2021 [Page 11] Internet-Draft IP Aliasing Support for EVPN June 2021 6. Load Balancing of Unicast Packets The procedures for load balancing of Unicast Packets do not change from [RFC7432] 7. Security Considerations The mechanisms in this document use EVPN control plane as defined in [RFC7432]. Security considerations described in [RFC7432] are equally applicable. This document uses MPLS and IP-based tunnel technologies to support data plane transport. Security considerations described in [RFC7432] and in [RFC8365] are equally applicable. 8. IANA Considerations No IANA considerations. 9. Contributors 10. Acknowledgments 11. References 11.1. Normative 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, . [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, . [RFC8365] Sajassi, A., Ed., Drake, J., Ed., Bitar, N., Shekhar, R., Uttaro, J., and W. Henderickx, "A Network Virtualization Overlay Solution Using Ethernet VPN (EVPN)", RFC 8365, DOI 10.17487/RFC8365, March 2018, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . Sajassi, et al. Expires December 10, 2021 [Page 12] Internet-Draft IP Aliasing Support for EVPN June 2021 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8584] Rabadan, J., Ed., Mohanty, S., Ed., Sajassi, A., Drake, J., Nagaraj, K., and S. Sathappan, "Framework for Ethernet VPN Designated Forwarder Election Extensibility", RFC 8584, DOI 10.17487/RFC8584, April 2019, . 11.2. Informative References [I-D.ietf-bess-evpn-inter-subnet-forwarding] Sajassi, A., Salam, S., Thoria, S., Drake, J. E., and J. Rabadan, "Integrated Routing and Bridging in EVPN", draft- ietf-bess-evpn-inter-subnet-forwarding-13 (work in progress), February 2021. [I-D.ietf-bess-evpn-prefix-advertisement] Rabadan, J., Henderickx, W., Drake, J. E., Lin, W., and A. Sajassi, "IP Prefix Advertisement in EVPN", draft-ietf- bess-evpn-prefix-advertisement-11 (work in progress), May 2018. Authors' Addresses A. Sajassi (editor) Cisco Systems Email: sajassi@cisco.com G. Badoni Cisco Systems Email: gbadoni@cisco.com P. Warade Cisco Systems Email: pwarade@cisco.com S. Pasupula Cisco Systems Email: surpasup@cisco.com Sajassi, et al. Expires December 10, 2021 [Page 13] Internet-Draft IP Aliasing Support for EVPN June 2021 J. Drake (editor) Juniper Email: jdrake@juniper.net J. Rabadan (editor) Nokia 777 Middlefield Road Mountain View, CA 94043 USA Email: jorge.rabadan@nokia.com Sajassi, et al. Expires December 10, 2021 [Page 14]