You must select the VRF for global IPv4 or IPv6 options before entering commands; not all Global Router parameters are configurable on other VRF instances.
Layer 1 and Layer 2 information (including VLAN information) is global and is not maintained for each VRF instance. However, you can associate a set of VLANs with a VRF instance.
A VLAN cannot belong to more than one VRF instance at a time. When you create a VLAN, more than one physical port can belong to it. You can associate a VRF instance with more than one IPv4 or IPv6 interface (a physical Ethernet port or a VLAN).
Perform physical port assignment at the VLAN and brouter port level. A VRF instance inherits all the ports assigned to its VLANs and brouter ports. You cannot directly assign a physical port to a VRF instance, but it is implicitly assigned when you associate the VRF with VLANs or brouter ports.
For IPv4, after you configure interVRF route redistribution between two VRF instances, avoid overlapping IP addresses between these two VRF instances.
When you configure VRF Lite, remember the following rules:
You can connect two VRFs from the same system with an external cable.
An IPv4 or IPv6 routable VLAN can become a member of a VRF.
An IPv4 or IPv6 interface can belong to only one VRF.
A VRF can exist even if no interfaces are assigned to it.
Routing policies apply to VRFs on an individual basis.
Multiple VRFs on the same node can function in different autonomous systems.
Following rules apply to IPv4 interfaces specifically:
If you configure an IPv4 interface without specifying the VRF instance, it is mapped to VRF 0 by default.
VRF Lite supports SMLT and RSMLT.
VRF Lite supports RIP in and out policies.
VRF Lite supports OSPF in and out (accept and redistribute) policies.
Before you delete a VRF instance, disable OSPF. Deleting a VRF instance deletes the OSPF instance if OSPF is disabled.
When you create a VRF instance, an OSPF instance is not automatically created. To activate OSPF on a VRF instance, first create an OSPF instance, and then enable OSPF.
You can configure a VRF so it can have IP interfaces with OSPF, RIP, static routes, and policies simultaneously.
Every IPv4 interface is a member of VRF 0 unless explicitly defined to belong to another VRF.
For the 5320 Series, only 5320-48P-8XE and 5320-48T-8XE support more than one VRF with IP configuration.
The 16- and 24-port 5320 Series models support a single active VRF with IP configuration; the VRF can be the Global Routing Table (GRT) or a non-default VRF:
The GRT becomes the active VRF if you attach an IP interface to a VLAN. Otherwise, the first non-default VRF you create becomes the active VRF.
If the GRT is the active VRF, you cannot create a second VRF.
You cannot create more than one non-default VRF.
You cannot configure IP interfaces in the GRT if the active VRF is a non-default VRF.
To transition the active VRF from the GRT to a non-default VRF, remove all IP interfaces and then create the non-default VRF.
To transition the active VRF from a non-default VRF to the GRT, first remove all router, ARP, and IP interfaces. Delete the VRF, and then add IP interfaces to the GRT.
Support for a single active VRF affects other features that rely on VRFs with IP configuration:
Fabric Extend — you must configure a route-map policy to suppress IS-IS redistribution of the FE tunnel subnet:
Configure route-maps to not permit redistribution of the local route used as the tunnel source address (ip-tunnel-source-address command).
Configure an accept policy to deny IS-IS routes that overlap with the destination tunnel IP address.
IP Shortcuts and Layer 3 VSN - You cannot configure the IP source address (ip-source-address command) as an IP address in the GRT if the active VRF is a non-default VRF.