IS-IS Extensions to Support Route Tagging

To control the transmission of routes into IS-IS, or to control transmission of IS-IS routes between different IS-IS levels, you can tag routes with certain attributes. IS-IS routes can carry these attributes, which the routing policies can use to export and import routes between different IS-IS levels. A sub-TLV to the IP prefix TLV is used to carry the tag or attribute on the routes.

Note: Route tagging does not work when IS-IS traffic engineering is disabled.