LDP Configuration Commands 751route-tag Syntaxroute-tag tag-numberundo route-tagViewOSPF protocol viewParametertag-number: Tag value to identify VPN import route, in the range of 0 to4294967295. By default, its first two bytes are fixed to 0xD000, while the last twobytes are the ASN of local BGP. For example, if the local BGP ASN is 100, then thedefault tag value in decimal is 3489661028. The value is an integer from 0 to4294967295.DescriptionUse the route-tag command to specify a tag value to identify VPN import route.Use the undo route-tag command to restore the default value.If a VPN Site is linked to multiple PEs, when a route learned from MPLS/BGP isadvertised by a PE router via its type-5 or type-7 LSA to the VPN Site, the routemay be received by another PE router. This will result in routing loop. To avoidrouting loop, you should configure Route-tag and you are recommended toconfigure the same route-tag for the PEs in the same VPN domain. The Route-tagis included in the type-5/-7 LSA. It is not transmitted in the extended communityattributes of BGP, and thus it is limited in the local area. Therefore, it can only beconfigured and function on the PE router which receives BGP routes and generatesOSPF LSA.Configure Route-tag in OSPF protocol view. Different processes can be configuredwith a same Route-tag. You can configure the same Route-tag using differentcommands, but they are different in priority.■ Those configured with the import-route command are of the highest priority.■ Those configured with the route-tag command are in the second place interms of priority.■ Those configure with the default tag command are of the lowest priority.If the Tag included in the type-5/-7 LSA is identical with its existing Tag, the LSAreceived will be neglected in route calculation.c CAUTION: The Route-tag configured will not be validated until the reset ospfcommand is executed.Related command: import-route and default.Example# Configure Route-tag 100 to OSPF process 100.[3Com-ospf-100] route-tag 100OSPF: Process 100’s route tag has been changed
