Tiered link building uses two levels of links to boost your site’s SEO. Tier 1...

https://landensinsightfulperspectives.wpsuo.com/what-should-i-do-if-my-tier-1-backlink-disappears

Tiered link building uses two levels of links to boost your site’s SEO. Tier 1 links point directly to your main pages and carry the most weight. Tier 2 links support Tier 1 by linking to those first-level pages