Use this command to specify an OSPF VPN routing and forwarding (VRF) domain tag.


domain-tag tag
no domain-tag


tag Specifies an OSPF VRF domain tag value. Valid values are 0 - 4294967295. Default value is 0.


The OSPF VRF domain tag default value is 0.


VRF configuration, OSPF router configuration.


The configuration and inclusion of the OSPF VRF domain tag is required for PE-CE protocol enabled systems to be backward compatible with systems that do not set the PE-CE protocol DN bit in type 5 LSAs. When a prefix is received from a BGP speaker and redistributed into the PE-CE protocol enabled OSPF instance, the OSPF process for the VRF is given a domain tag. In the event that the customer site attempts to re-advertise the prefix to another PE using the same domain tag, the domain tag will be matched and the prefix will not be accepted by the second PE for redistribution into BGP. Setting the same domain tag for all backbone PE routers on the same VPN prevents routing loops.

Setting the OSPF VRF domain tag is optional when the PE-CE protocol is enabled for all PE backbone routers for a given VRF. If legacy PE routers that do not support the PE-CE protocol are present in the VRF backbone, set the domain tag for this router to agree with the domain tag of the legacy router.

The PE-CE protocol (RFC 4577) must be enabled using enable-pe-ce to set the OSPF VRF domain tag.

The “no” form of this command restores the default domain tag value of 0.


This example shows how to set the OSPF VRF domain tag value to 100 for VRF doc:

System(su)->router doc
System(su-doc-config)->router ospf 10
System(su-doc-config-ospf-10)->domain-tag 100