Two-Tier DNS Architecture for Scalable Resolution
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Solution Overview
Problem
Current DNS services face inefficiencies in resource utilization and scalability, as all DNS records are typically distributed to all servers, leading to high computation and memory consumption, and existing solutions often provide a single IP address for DNS servers, which can limit scalability.
Innovation Solution
A two-tier DNS service architecture is deployed, with first-tier service machines identifying and forwarding DNS requests to second-tier service machines grouped by domain names, allowing for scalable and efficient processing through virtual IP addresses and load balancing across multiple geographic sites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all DNS records are distributed to all DNS servers, then each server can resolve any DNS request independently, but computation and memory resources are consumed excessively
Solution Approach 1:
The patent divides the DNS service into two tiers: first-tier servers that receive and route DNS requests, and second-tier servers that specialize in resolving specific domain names. This segmentation allows first-tier servers to have minimal DNS records (only for routing) while second-tier servers store detailed records for their specialized domains, reducing overall resource consumption while maintaining resolution capability.
Solution Approach 2:
The first-tier DNS servers act as intermediaries between external clients and second-tier specialized DNS servers. They receive DNS requests, determine the appropriate second-tier server based on the domain name, and forward requests accordingly. This intermediary role eliminates the need for all servers to store and process all DNS records directly.
2Device complexity
If a single IP address is provided for DNS servers, then the system is simple to manage, but scalability is limited when scaling up DNS service
Solution Approach 1:
The patent segments the IP addressing into two levels: a single public anycast IP address for first-tier servers that provides external access points, and multiple private IP addresses for second-tier servers that enable internal scalability. This allows the system to present a simple external interface while maintaining complex internal scalability.
Solution Approach 2:
The patent introduces a hierarchical dimension to IP address management by separating public-facing anycast addresses from internal private addresses. This dimensional separation allows external clients to interact with a simple single IP address while the system internally utilizes multiple addresses across different tiers for scalable deployment.
3Productivity
If DNS service is scaled up by adding more IP addresses, then service capacity increases, but system complexity and resource distribution become inefficient
Solution Approach 1:
The patent segments DNS service capacity across two tiers: first-tier servers handle request routing with minimal configuration, while second-tier servers provide specialized resolution capacity. This segmentation allows capacity scaling through adding second-tier servers without increasing first-tier complexity, as routing decisions are based on simple domain name patterns rather than complex IP address management.
Solution Approach 2:
First-tier servers act as intermediaries that simplify the scaling process. When capacity needs to increase, new second-tier servers can be added with specialized domain knowledge without requiring changes to external client configurations or first-tier routing logic, maintaining system simplicity while increasing productivity.
4Ease of operation
If all DNS servers provide full DNS service endpoints, then any server can handle any request, but failure domains are large and resilience is reduced
Solution Approach 1:
The patent segments the failure domain by organizing second-tier servers to specialize in specific domain names or domain families. If a second-tier server fails, only the specific domains it handles are affected, not the entire DNS service. First-tier servers maintain service uniformity by providing consistent request routing across all domains.
Solution Approach 2:
The patent applies local quality by giving different second-tier servers specialized knowledge for different domain names rather than making all servers identical. Each second-tier server is optimized for its specific domain portfolio, improving reliability through localized expertise while first-tier servers maintain uniform routing operations across all requests.
Data Source
AI summary
Some embodiments provide a two-tier DNS (Domain Name System) service for processing DNS requests. In some embodiments, the two-tier DNS service deploys first and second tiers of service machines, with the second-tier having several groups of service machines each of which is configured to resolve DNS requests for a different set of domain names than the other second-tier group(s). Each service machine in the first-tier is configured to identify the second-tier group responsible for each particular DNS request that the service machine receives for each particular domain name, and to forward the particular DNS request to the second-tier group that it identifies for the particular DNS request. The first-tier DNS service in some embodiments has only one group of service machines. Each first or second service machine group in some embodiments can have one or more service machines, and can be scaled up or down to add or remove service machines to the group (e.g., through an active/active layer 3 scaleout with BGP). In some embodiments, two different second-tier service groups can process DNS requests for two or more different FQDNs (fully qualified domain names) that are part of the same domain, and/or for two or more different FQDNs that are part of different domains.