How does the Internet benefit from using a hierarchical architecture?

What will be an ideal response?

The hierarchical architecture permits Internet service providers (ISP) of different levels,
which improves scalability and fault tolerance. For example, Tier 1 providers, such as AT&T
and Verizon, provide national and international connections and are optimized for carrying
huge loads of traffic across the globe. Tier 2 providers are smaller and often provide regional
service. Tier 3 providers are smaller yet and focus on getting end users on the Internet. Each
tier can optimize its services for its unique role. The hierarchical structure also means that
network traffic that is destined for a service that is local to the sender does not need to tra
verse to a central point for distribution.