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

https://wiki-cable.win/index.php/Is_Four_Dots_a_Good_Option_for_AI_SEO_Services%3F

Tiered link building uses two levels of backlinks to boost your site’s authority. Tier 1 links point directly to your site, while Tier 2 links support those Tier 1 backlinks