A national retailer has 60 stores with MPLS color gold and broadband color blue on each WAN Edge, and policy requires gold TLOCs talk only to gold and blue only to blue to honor transport contracts. Adjacencies are forming across colors today. Which restrict configuration on colors limits tunnel formation across colors as required?

The requirement is strict color-segregated tunnel formation across 60 dual-transport sites honoring MPLS gold to gold and broadband blue to blue contracts, and the restrict attribute on a color directly controls TLOC adjacency rules so that when both colors are marked restrict on every WAN Edge, a TLOC will only form BFD and IPsec tunnels to same-color peers and cross-color adjacencies never establish. Restricting only hub routers is a sound hierarchical design for scaling hubs but fails here because spokes without restrict still freely build gold to blue tunnels among themselves, leaving most violations intact. Adding an unrestrict default color for fallback is a common resilience pattern for last-resort connectivity but fails here because policy forbids any cross-color tunnels and the extra color provides an explicit bridging path. Using centralized data policy is a valid and widely used method to pin applications to preferred transports, but it fails here because policy steers traffic over existing tunnels and does not prevent underlying cross-color TLOC adjacency formation. For exam purposes remember restrict is configured per-color under tunnel interface configuration, must match on both ends to enforce same-color only, and is distinct from OMP, control policy, or data policy traffic engineering. As a practical check verify with show sdwan bfd sessions that every peer pair matches color to color before auditing contract compliance across all stores.