Users Guide

*> Route distinguisher: 110.111.170.107:64536
[3]:[0]:[32]:[110.111.170.107]/152 110.111.170.107 0 100 0 100 101 ?
Display the EVPN routes for host MAC addresses
OS10# show evpn mac
Type -(lcl): Local (rmt): remote
EVI Mac-Address Type Seq-No Interface/Next-Hop
50 00:00:00:aa:aa:aa rmt 0 55.1.1.3
50 00:00:00:cc:cc:cc lcl 0 ethernet1/1/8:1
OS10# show evpn mac evi 50
Type -(lcl): Local (rmt): remote
EVI Mac-Address Type Seq-No Interface/Next-Hop
50 00:00:00:aa:aa:aa rmt 0 55.1.1.3
50 00:00:00:cc:cc:cc lcl 0 ethernet1/1/8:1
VXLAN BGP EVPN routing
This section describes how EVPN implements overlay routing between L2 segments associated with EVIs belonging to the
same tenant on a VTEP. IETF draft draft-ietf-bess-evpn-inter-subnet-forwarding-05 describes EVPN inter-subnet forwarding,
Integrated Routing and Bridging (IRB), and how to use EVPN with IP routing between L2 tenant domains.
You set up overlay routing by assigning a VRF to each tenant, creating a virtual-network interface, and assigning an IP subnet
in the VRF to each virtual-network interface. The VTEP acts as the L3 gateway that routes traffic from one tenant subnet
to another in the overlay before encapsulating it in the VXLAN header and transporting it over the underlay fabric. On virtual
networks that associate with EVIs, EVPN IRB is enabled only after you create a virtual-network interface.
When you enable IRB for a virtual network/EVI, EVPN operation on each VTEP also advertises the local tenant IP-MAC bindings
learned on the EVPN-enabled virtual networks to all other VTEPs. The local tenant IP-MAC bindings are learned from ARP or
ICMPv6 protocol operation. They advertise as EVPN Type-2 BGP route updates to other VTEPs, each of whom then imports
and installs them as ARP/IPv6 neighbor entries in the dataplane.
To enable efficient traffic forwarding on a VTEP, OS10 supports distributed gateway routing. A distributed gateway allows
multiple VTEPs to act as the gateway router for a tenant subnet. The VTEP that is located nearest to a host acts as its gateway
router.
To enable L3 gateway/IRB functionality for BGP EVPN, configure a VXLAN overlay network and enable routing on a switch:
1. Create a non-default VRF instance for overlay routing. For multi-tenancy, create a VRF instance for each tenant.
2. Configure globally the anycast gateway MAC address used by all VTEPs.
3. Configure a virtual-network interface for each virtual network, (optional) assign it to the tenant VRF, and configure an IP
address. Then enable the interface.
4. Configure an anycast gateway IP address for each virtual network. OS10 supports distributed gateway routing.
EVPN supports different types of IRB routing for tenants, VMs, and servers, that connect to each VTEP:
● Centralized routing: For each tenant subnet, one VTEP is designated as the L3 gateway to perform IRB inter-subnet routing.
All other VTEPs perform L2 bridging.
● Distributed routing: For each tenant subnet, all VTEPs perform L3 gateway routing for the tenant VMs and servers
connected to a VTEP. In a large multi-tenant network, distributed routing allows for more efficient bandwidth use and
traffic forwarding. IRB routing is performed either:
○ Only on an ingress VTEP.
○ On both ingress and egress VTEPs.
Asymmetric IRB routing
In asymmetric IRB routing, IRB routing is performed only on ingress VTEPs. Egress VTEPs perform L2 bridging in the tenant
subnet.
An ingress VTEP directly routes packets to a destination host MAC address in the destination virtual-network VNI. An egress
VTEP only bridges packets to a host by removing the VXLAN header and forwarding a packet to the local Layer 2 domain using
the VNI-to-VLAN mapping.
VXLAN
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