BGP EVPN Multihoming Overview

BGP EVPN multihoming enhances redundancy for BGP EVPN by providing multiple, distinct Provider Edge (PE) connections (uplinks) for Customer Edge (CE) devices. This multi-attachment capability offers redundant, all-active connectivity to the EVPN core network and extends this redundancy across the entire network connected to the core.

BGP EVPN multihoming addresses common challenges associated with all-active redundancy, such as duplication and looping of Broadcast, Unknown unicast, and Multicast (BUM) traffic.

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Important Terminology for BGP EVPN Multihoming

The following are common terms used in reference to BGP EVPN Multihoming:

  • BUM: Broadcast, Unknown unicast, and Multicast
  • CE: Customer Edge
  • DF: Designated Forwarder
  • ES: Ethernet Segment
  • EVPN: Ethernet Virtual Private Network. A common implementation is Ethernet over VXLAN. This is the implementation outlined in this chapter.
  • EVI: Ethernet Virtual Instance
  • LAG: Link Aggregation Group
  • MAC: Media Access Control
  • PE: Provider Edge
  • RD: Route Distinguisher
  • SH: Split Horizon
  • VE: Virtual Entity. A set of virtualized network resources or devices that are connected to multiple uplinks or network paths.
  • VNI: Virtual Network Identifier
  • VTEP: Virtual Tunnel End Point. In BGP EVPN terms, a VTEP can also be referred to as a leaf.
  • VXLAN: Virtual eXtensible Local Area Network
Note: For more information on VXLAN-related terminology, refer to the VXLAN chapter.
Note: For more information on general BGP EVPN terminology, refer to BGP EVPN VXLAN.

Requirements

  • I believe this statement is just applicabe to FI. If you want it in the SZ content, remove the condition. Add your own requirements and conditionalize for SZ. If you do not have requirements, I will add the FI condition to the entire section
    BGP EVPN Multihoming is supported for RUCKUS ICX 7850 and ICX 7550 devices only.
Add conditions to below as necessary if this is not applicable to SZ

Considerations

  • All BGP EVPN singlehoming configurations are supported for BGP EVPN Multihoming. Refer to BGP EVPN VXLAN for more information.
  • In a BGP EVPN singlehomed environment, when a port goes down, all locally learned Media Access Control (MAC) addresses on that port become unreachable due to the absence of alternative paths. As a result, the Virtual Tunnel Endpoint (VTEP) initiates the withdrawal of these MAC addresses to other VTEPs in the network. However, in a BGP EVPN multihomed environment, if an Ethernet Segment (ES) becomes unavailable on one VTEP, the local MAC addresses associated with that ES may still be reachable through another local or multihomed member VTEP where the ES is still active. This redundancy ensures continued access to those MAC addresses through the remaining operational VTEP.
  • A maximum of two Virtual Tunnel End Points (VTEPs) are supported to participate in multihoming (Dualhoming).
  • It is recommended to configure anycast gateways on multihomed (MH) Virtual Entities (VEs) before configuring BGP EVPN MH. For more information on anycast gateways refer to the Anycast Gateway with VXLAN section.

Best Practices

  • To improve scalability and manageability, use RRs to reduce the number of BGP sessions in the network.
  • Enable ARP suppression to reduce ARP broadcast traffic within the VXLAN fabric.
  • Carefully manage Broadcast, Unknown unicast, and Multicast (BUM) traffic to prevent network congestion. Use features like IGMP snooping and multicast routing to control BUM traffic.
  • Secure your BGP sessions using authentication mechanisms like MD5. Additionally, implement access control lists (ACLs) to restrict BGP session establishment to trusted peers.
  • Plan for scalability by considering the number of VTEPs, VNIs, and the overall size of the EVPN fabric. Ensure your hardware and software can support the expected growth.

Prerequisites

  • Devices must support BGP EVPN and VXLAN protocols. For more details on BGP EVPN and VXLAN device support for RUCKUS ICX devices, refer to the RUCKUS FastIron Features and Standards Support Matrix..
  • While an Interior Gateway Protocol (IGP) such as OSPF or RIP can be enabled for underlay routing, it is recommended to employ OSPF for optimal underlay routing.
  • VLANs and VXLANs must be configured in advance.
  • Define the VTEPs (VXLAN Tunnel Endpoints) within the VXLAN topology.

BGP EVPN Multihoming Limitations

  • The maximum number of Ethernet Segment LAGs that can be locally configured on one device is 16. This includes both static and dynamic LAGs.
  • The maximum number of dual-homed sites is eight. The maximum number of VTEPs is sixteen so that a maximum of eight dualhomed sites can be configured.
  • The maximum number of member EVIs for one ES-LAG is capped at 100. This limit is implemented to maintain control over the number of Ethernet Auto-Discovery (EAD) routes generated in the network.
  • IPv6 is not supported.
  • eBGP is not supported.
Parent topic: BGP EVPN Multihoming