Virtual Routing and Forwarding (VRF) allows multiple instances of independent routing tables to co-exist within the same router simultaneously. Dell Enterprise SONiC supports a management VRF instance, a default VRF instance, and one or more non-default (tenant) VRF instances.
Three VRFs are used in the switch configuration examples: management, default, and one tenant VRF.
The management VRF is created with the command ip vrf mgmt
in SONiC and is always named mgmt
. This VRF separates the OOB management routing table used by the Management 0 interface from the in-band routing tables. For example, you can have the default route 0.0.0.0/0 in both the management VRF route table and the default VRF route table with each having a different gateway address. The routes will not conflict as the VRF dictates which route table is used. For this reason, using the management VRF is a best practice.
The default VRF is named default
in SONiC. Interfaces that are not placed in another VRF are automatically in the default VRF. For a stretched cluster deployment, the External Management and vSAN VLANs should remain in the default VRF.
In addition to the External Management and vSAN VLANs, the vMotion, VxRail node discovery, and cluster build VLANs are also kept in the default VRF in this example. As an option, the vMotion, node discovery, and cluster-build VLANs can be placed in a tenant VRF.
In SONiC, tenant VRF names must start with Vrf
and may contain up to fifteen alphanumeric characters. The VxRail VM guest VLAN is placed in a tenant VRF named Vrf1
in this example. This VRF is optional and is done to demonstrate switch configuration for tenant VRFs.