Huawei Huawei Segment Routing (SR) is a new MPLS paradigm in which each SR-capable router is required to advertise global MPLS labels or Segment IDs (SID ) for its attached prefixes by using link-state IGPs, e.g., IS- IS. One major challenge associated with such global MPLS label or SID advertisement mechanism is how to avoid a given global MPLS label or SID from being allocated by different routers to different prefixes. Although such global label or SID allocation collision problem can be addressed through manual allocation , it is error- prone and nonautomatic therefore may not be suitable in large-scale SR network environments. This document proposes an alternative approach for allocating and advertising global MPLS labels or SIDs via IS-IS so as to eliminate the potential risk of label allocation collision.