Scalability, reliability, and consistency in DNS

When we talk about any large-scale system, especially something as vast as DNS, there are three buzzwords that often come up: scalability, reliability, and consistency. These are like the three pillars that hold up any robust system. Let’s dive into how DNS checks off these crucial boxes.

Scalability

The DNS achieves high scalability through its hierarchical design with root, top-level domain, and authoritative name servers distributed worldwide. Roughly 1,000 replicated instances of 13 root-level servers handle the initial user queries. They point to TLD servers, which, in turn, point to authoritative servers managed by individual organizations. This hierarchical structure divides the load between different levels, allowing DNS to scale to serve billions of daily queries for the entire internet.

The distributed nature of DNS also contributes to its scalability. Redundant replicated DNS servers are located strategically...