IPv6 Underlay for an IPv4 EVPN-VXLAN Fabric

date_range 27-Feb-25

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Overview

When configuring an IPv6 underlay, an additional challenge might be present for a network with an existing IPv4 EVPN-VXLAN overlay. In such a network, the virtual tunnel endpoint (VTEP) address is IPv4. The VXLAN overlay extends virtual tunnels (VTs) between VTEPs over the underlying IP fabric. To add an IPv6 underlay, the network needs to distribute this IPv4 address to the IPv6-only underlay. Certain platforms and releases support configuring your AI-ML data center to accomplish this when the IPV6 underlay is external BGP (EBGP).

Topology

This configuration is suited for a network with the following topology:

Figure 1: Network topology of IPv4 EVPN-VXLAN overlay with an IPv6 underlay

Configuration

Follow these steps to send IPV4 network layer reachability information (NLRI) over the IPv6 address family in your EBGP underlay.

Enable BGP to send IPV4 NLRI over the IPv6 address family.

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user@host# set protocols bgp group bgp-underlay family inet unicast extended-nexthop

Verify that the IPv4 loopback address, which functions as the VTEP address, is reachable over the IPv6 address.

In this example, the VTEP address is 192.168.255.255.

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user@host> show route forwarding-table destination 192.168.255.255 

Routing table: default.inet
Internet:
Destination             Type  RtRef  Next hop       Type  Index  NhRef  Netif
192.168.255.255/32      user    0                   ulst   9074   1      
2001:db8:3c4d:5::ucst   6000    1    et-0/0/3.0     sftw   9070   1      et-0/0/3.0
2001:db8:3c4d:6::ucst   6001    1    et-0/0/12.0    sftw   9073   1      et-0/0/12.0

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user@host> show route table macvrf1.evpn.0

macvrf1.evpn.0: 2 destinations, 3 routes (2 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
 
2001:db8:3c4d:7::/248 IM            
                   *[EVPN/170] 00:21:22
                       Indirect
2001:db8:3c4d:8::/248 IM            
                   *[BGP/170] 00:02:51, localpref 100, from 192.168.1.0
                      AS path: 65102 65003 I, validation-state: unverified
>  to 2001:db8:3c4d:5:: via et-0/0/3.0
                       to 2001:db8:3c4d:6:: via et-0/0/12.0
                    [BGP/170] 00:02:47, localpref 100, from 192.168.2.0
                      AS path: 65101 65003 I, validation-state: unverified
>  to 2001:db8:3c4d:5:: via et-0/0/3.0
                       to 2001:db8:3c4d:6:: via et-0/0/12.0

You can now run IPv4 EVPN-VXLAN on an IPV6-only underlay.

Platform Support

See Feature Explorer for platform and release support.

AI-ML Data Center Feature Guide

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IPv6 Underlay for an IPv4 EVPN-VXLAN Fabric

Overview

Topology

Configuration

Platform Support

Related Documentation

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