Users Guide

2. Configure port interfaces as trunk members and remove the access VLAN in Interface mode.
interface ethernet node/slot/port[:subport]
switchport mode trunk
no switchport access vlan
exit
3. Assign the trunk interfaces as untagged members of the virtual network in VIRTUAL-NETWORK mode. You cannot use
the reserved VLAN ID for a legacy VLAN or for tagged traffic on member interfaces of virtual networks.
virtual-network vn-id
member-interface ethernet node/slot/port[:subport] untagged
exit
If at least one untagged member interface is assigned to a virtual network, you cannot delete the reserved untagged VLAN ID.
If you reconfigure the reserved untagged VLAN ID, you must either reconfigure all untagged member interfaces in the virtual
networks to use the new ID or reload the switch.
Enable overlay routing between virtual networks
The previous sections describe how a VTEP switches traffic between hosts in the same L2 tenant segment on a virtual network,
and transports traffic over an IP underlay fabric. This section describes how a VTEP enables hosts in different L2 segments
belonging to the same tenant VRF to communicate with each other.
NOTE: On the S4248-ON switch, IPv6 overlay routing between virtual networks is not supported with static VXLAN. IPv6
overlay routing is, however, supported with BGP EVPN asymmetric IRB.
Each tenant is assigned a VRF and each virtual-network interface is assigned an IP subnet in the tenant VRF. 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 IP underlay fabric.
To enable host traffic routing between virtual networks, configure an interface for each virtual network and associate it to
a tenant VRF. Assign a unique IP address in the IP subnet range associated with the virtual network to each virtual-network
interface on each VTEP.
To enable efficient traffic forwarding on a VTEP, OS10 supports distributed and centralized gateway routing. A distributed
gateway means that multiple VTEPs act as the gateway router for a tenant subnet. The VTEP nearest to a host acts as its
gateway router. To support seamless migration of hosts and virtual machines on different VTEPs, configure a common virtual IP
address, known as an anycast IP address, on all VTEPs for each virtual network. Use this anycast IP address as the gateway IP
address on VMs.
To support multiple tenants when each tenant has its own L2 segments, configure a different IP VRF for each tenant. All
tenants share the same VXLAN underlay IP fabric in the default VRF.
1. Create a non-default VRF instance for overlay routing in Configuration mode. For multi-tenancy, create a VRF instance for
each tenant.
ip vrf tenant-vrf-name
exit
2. Configure the anycast gateway MAC address all VTEPs use in all VXLAN virtual networks in Configuration mode.
When a VM sends an Address Resolution Protocol (ARP) request for the anycast gateway IP address in a VXLAN virtual
network, the nearest VTEP responds with the configured anycast MAC address. Configure the same MAC address on all
VTEPs so that the anycast gateway MAC address remains the same if a VM migrates to a different VTEP. Because the
configured MAC address is automatically used for all VXLAN virtual networks, configure it in global Configuration mode.
ip virtual-router mac-address mac-address
Example:
OS10(config)# ip virtual-router mac-address 00:01:01:01:01:01
3. Configure a virtual-network interface, assign it to the tenant VRF, and configure an IP address.
The interface IP address must be unique on each VTEP, including VTEPs in VLT pairs. You can configure an IPv6 address
on the virtual-network interface. Different virtual-network interfaces you configure on the same VTEP must have virtual-
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VXLAN