Users Guide

no shutdown
exit
4. Configure an anycast gateway IPv4 or IPv6 address for each virtual network in INTERFACE-VIRTUAL-NETWORK mode. This
anycast IP address must be in the same subnet as the IP address of the virtual-network interface in Step 3.
Configure the same IPv4 or IPv6 address as the anycast IP address on all VTEPs in a virtual network. All hosts use the
anycast gateway IP address as the default gateway IP address in the subnet that connects to the virtual-network interface
configured in Step 3. Configure the anycast gateway IP address on all downstream VMs. Using the same anycast gateway
IP address allows host VMs to move from one VTEP to another VTEP in a VXLAN. Dell EMC recommends using an anycast
gateway in both VLT and non-VLT VXLAN configurations.
interface virtual-network vn-id
ip virtual-router address ip-address
Configuration notes for virtual-network routing:
● VXLAN overlay routing includes routing tenant traffic on the ingress VTEP and bridging the traffic on the egress VTEP. The
ingress VTEP learns ARP entries and associates all destination IP addresses of tenant VMs with the corresponding VM MAC
addresses in the overlay. On the ingress VTEP, configure a virtual network for each destination IP subnet even if there are
no locally attached hosts for an IP subnet.
● Routing protocols, such as Open Shortest Path First (OSPF) and BGP, are not supported on the virtual-network interface
in the overlay network. However, static routes that point to a virtual-network interface or to a next-hop IP address that
belongs to a virtual-network subnet are supported.
● When you add a static route in the overlay, any next-hop IP address that belongs to a virtual-network subnet must be
the only next-hop for that route and cannot be one of multiple ECMP next-hops. For example, if you enter the following
configuration commands one after the other, where 10.250.0.0/16 is a virtual-network subnet, only the first next-hop is
active on the switch.
OS10(config)# ip route 0.0.0.0/0 10.250.0.101
OS10(config)# ip route 0.0.0.0/0 10.250.0.102
If the next-hop is a pair of dual-homed VTEPs in a VLT domain, a workaround is to configure the same anycast gateway IP
address on both VTEPs and use this address as the next-hop IP address.
● VLT peer routing is not supported in a virtual network. A packet destined to the virtual-network peer MAC address L2
switches instead of IP routes. To achieve active-active peer routing in a virtual network, configure the same virtual anycast
gateway IP and MAC addresses on both VTEP VLT peers and use the anycast IP as the default gateway on the VMs.
● Virtual Router Redundancy Protocol (VRRP) is not supported on a virtual-network interface. Configure the virtual anycast
gateway IP address to share a single gateway IP address on both VTEP VLT peers and use the anycast IP as default gateway
on the VMs.
● Internet Group Management Protocol (IGMP) and Protocol-Independent Multicast (PIM) are not supported on a virtual-
network interface.
● IP routing of incoming VXLAN encapsulated traffic in the overlay after VXLAN termination is not supported.
The following tables show how to use anycast gateway IP and MAC addresses in a data center with three virtual networks and
multiple VTEPs:
● Globally configure an anycast MAC address for all VTEPs in all virtual networks. For example, if you use three VTEP switches
in three virtual networks:
Table 41. MAC address for all VTEPs
Virtual network VTEP Anycast gateway MAC address
VNID 11 VTEP 1
VTEP 2
VTEP 3
00.11.22.33.44.55
00.11.22.33.44.55
00.11.22.33.44.55
VNID 12 VTEP 1
VTEP 2
VTEP 3
00.11.22.33.44.55
00.11.22.33.44.55
00.11.22.33.44.55
VNID 13 VTEP 1
VTEP 2
00.11.22.33.44.55
00.11.22.33.44.55
934 VXLAN