ZTE Corporation ZTE Corporation Cisco Systems Cisco Systems H3C Both SR-MPLS prefix-SID and IPv4 prefix may be configured as anycast and as such the same value can be advertised by multiple routers. It is useful for other routers to know that the advertisement is for an anycast identifier. Each prefix is advertised along with an 8-bit field of capabilities,by using the flag flield in the OSPFv2 Extended Prefix TLV, but the definition of anycast flag to identify the prefix as anycast has not yet been defined. This document defines a new flag in the OSPFv2 Extended Prefix TLV Flags to advertise the anycast property.