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

https://www.bookmarking-keys.win/tiered-link-building-is-an-efficient-way-to-boost-your-site-s-authority-without

Tiered link building uses two levels of backlinks to boost your site’s ranking. Tier 1 links point directly to your site and hold the most value. Tier 2 links support Tier 1, helping them pass more authority