Cisco Systems Cisco Systems To accommodate situations where the current requirements for the BGP Identifier are not met, this document relaxes the definition of the BGP Identifier to be a 4-octet, unsigned, non-zero integer and relaxes the "uniqueness" requirement so that only Autonomous-System-wide (AS-wide) uniqueness of the BGP Identifiers is required. These revisions to the base BGP specification do not introduce any backward compatibility issues. This document updates RFC 4271. [STANDARDS-TRACK]