API Guide

1. Create a reserved VLAN ID to assign untagged traffic on member interfaces to a virtual network in CONFIGURATION mode. The

VLAN ID is used internally for all untagged member interfaces on the switch that belong to virtual networks.

virtual-network untagged-vlan untagged-vlan-id

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

3. Configure a virtual-network interface, assign it to the tenant VRF, and configure an IP address.

VXLAN