You cannot define the VPN routing and forwarding (VRF) instance name in VRF configuration mode. A VRF instance name is defined by issuing the vrf definition command in global configuration mode. The syntax of the vrf definition command is vrf definition vrfname, where vrfname is any name that you want to assign to the VRF, except default. After you issue the vrf definition vrfname command, the router will be placed into VRF configuration mode, where you can issue commands to configure other features of the VRF.
If you issue the vrf definition default command on a Cisco router, a VRF instance will be created with the name configured to a NULL value. The NULL value acts as a VRF name placeholder until a default VRF name can be defined.
You can assign a route distinguisher (RD) in VRF configuration mode. To assign an RD to a VRF, issue the rd routed istinguisher command. Configuring an RD creates the routing tables and the forwarding tables for the VRF instance.
You can configure shared route targets between IPv4 and IPv6 in VRF configuration mode. To configure a shared route target, issue the routetarget [import | export | both] routetargetextcommunity command. Specifying the import keyword imports routing information from the community specified by the route target extcommunity parameter. Conversely, the export keyword sends routing information to the specified community. The both keyword imports routing information to and exports routing information from the specified community. To configure separate route target policies for IPv4 and IPv6, you should first issue the addressfamily command, which places the router into address family configuration mode.
You can associate a Simple Network Management Protocol (SNMP) context in VRF configuration mode. To associate an SNMP context, issue the context contextname command, where contextname is the name of the SNMP context you want to assign.
You can update a virtual private network (VPN) ID in VRF configuration mode. The VPN ID consists of a 3byte Organizationally Unique Identifier (OUI) and a 4byte VPN index. To update a VPN ID for a VRF, issue the vpn id oui: vpn-index command.