Tiered link building uses two levels of links to boost your site’s authority....

https://www.sierrabookmarking.win/tiered-link-building-organizes-backlinks-into-two-groups-tier-1-links-point

Tiered link building uses two levels of links to boost your site’s authority. Tier 1 links point straight to your site, while Tier 2 links support those Tier 1 links. This approach helps improve your rankings safely and steadily