Content-Based Sharding and Routing in CDN Systems
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Solution Overview
Problem
Existing Content Delivery Network (CDN) systems face inefficiencies in data sharding and routing, leading to cache resource overloads and increased latency due to cache misses, and lack the ability to make routing decisions based on metadata, resulting in suboptimal distribution of content across points of presence (PoPs).
Innovation Solution
Implementing a hashing mechanism and encoding domain names to redirect client requests to specific PoPs, allowing for improved cache utilization and metadata-based routing decisions, thereby optimizing content distribution and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If content is distributed across multiple PoPs using traditional DNS routing, then content availability is improved, but cache resource utilization becomes inefficient and latency increases
Solution Approach 1:
The patent segments content into different shards and distributes them to specific PoPs based on hashing of content identifiers. This segmentation allows precise routing of content requests to the PoP that holds the required shard, avoiding cache misses and reducing latency while maintaining content availability across the distributed network.
Solution Approach 2:
The patent changes the routing parameter from traditional DNS-based geographic routing to hash-based content identifier routing. By encoding content identifiers in domain names and using hashing mechanisms, the system directs requests to the specific PoP holding the content shard, improving cache hit rates and reducing latency.
2Device complexity
If traditional DNS routing is used without metadata, then system complexity is reduced, but routing decisions become suboptimal
Solution Approach 1:
The patent introduces metadata as an intermediary layer between the DNS system and content routing decisions. The metadata, encoded in domain names and containing content identifiers and routing information, enables intelligent routing decisions without significantly increasing system complexity. The DNS resolver acts as a mediator that decodes and processes this metadata to make optimal routing decisions.
3Productivity
If content is cached at specific PoPs, then cache hit rate is improved, but cache resource capacity is limited
Solution Approach 1:
The patent segments the overall content storage capacity across multiple PoPs, with each PoP holding specific content shards. This segmentation allows the system to achieve high cache hit rates by directing requests to the appropriate PoP while each individual PoP operates within its capacity constraints. The distributed architecture effectively increases total cache capacity without requiring any single PoP to exceed its resource limits.
Data Source
AI summary
System and methods are provided for sharding at the content level and routing content requests. Each point of presence (PoP) can initially identify the PoP that should serve content by using hashing. A PoP can encode a domain name with the identified PoP in metadata and redirect the client computing device. A client computing device transmits a DNS query for the encoded domain name. A DNS server receives the encoded domain name and decrypts and decodes the domain name label. The DNS server uses the decrypted and decoded metadata to make a further routing decision. The DNS server sends, to the client computing device, a DNS reply with the Internet Protocol (IP) address of the selected PoP. The client computing device requests content from the PoP identified by the provided IP address.