Tiered link building uses two levels of backlinks to boost your site’s SEO....

https://www.tool-bookmarks.win/tiered-link-building-uses-two-levels-of-backlinks-to-boost-your-site-s-ranking

Tiered link building uses two levels of backlinks to boost your site’s SEO. Tier 1 links point directly to your site and carry the most value. Tier 2 links support your Tier 1 links, making them stronger and safer