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

https://www.yankee-bookmarkings.win/tiered-link-building-helps-boost-your-website-s-seo-by-building-strong

Tiered link building uses two levels of links to boost your site’s ranking. Tier 1 links point directly to your site and carry real weight. Tier 2 links support those Tier 1 links, making them stronger and more effective