Data Center Interconnect (DCI) between VLT domains is supported in Dell EMC SmartFabric OS10 with the VRRP feature across the VLT domains (eVLT). With Dell EMC SmartFabric OS10, VRRP can be configured for dual VLT domains to form an eVLT topology, as shown in the following figure. The same VRRP group-id enables a common virtual IP address across both the VLT domains. Therefore, VM migration from DC-1 to DC-2 can be initiated without any dependency while retaining the VM IP address and gateway IP address.
The VRRP group for the configured VLANs should be the same VRRP group id in both VLT domains. With this implementation, only one of the nodes is selected as the VRRP Master, where the other three nodes each act as a standby for that VRRP group. For example, the virtual IP address 192.168.1.254 is retained across both of the DCs. If a VM with a default gateway of 192.168.1.254 is migrated from DC-1 to DC-2, the VM can retain its IP address and continue to forward and receive traffic without changes.
Upstream devices from the VLT domains can have static routing, or any other dynamic routing protocols, to support the N-S traffic. The host can still be reached if the traffic to the VM host lands at any upstream DC, ensuring high availability for the application and services.