Proposed Update to BGP Link-State SPF NLRI Selection Rules

For network scenarios such as Massively Scaled Data Centers (MSDCs), BGP is extended for Link-State (LS) distribution and the Shortest Path First (SPF) algorithm based calculation. BGP-LS-SPF leverages the mechanisms of both BGP protocol and BGP-LS protocol extensions, with new selection rules defined for BGP-LS-SPF NLRI. This document proposes some updates to the BGP-LS-SPF NLRI selection rules, so as to improve the route updates and convergence, while consistent SPF computation result can still be achieved. This document updates the NLRI selection rules in I-D.ietf-lsvr-bgp-spf.