DNS Cache Flushing on IP Family Transitions
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Solution Overview
Problem
DNS cache entries become invalid when a device switches between networks with different IP families, such as IPv4 and IPv6, leading to performance issues and unnecessary DNS lookups, as existing systems fail to efficiently validate cache entries during network transitions.
Innovation Solution
The system detects changes in network interfaces and IP families, implementing a cache flushing policy to validate and update DNS cache entries, ensuring validity and reducing cache misses by flushing invalid entries and maintaining consistency across compatible IP families.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DNS cache entries are maintained across network transitions, then lookup efficiency is improved, but cache validity deteriorates when IP family changes occur
Solution Approach 1:
The system performs preliminary validation of DNS cache entries by checking IP family compatibility before using cached data. When a network transition is detected, the system proactively validates whether the cached IP addresses are still compatible with the new network's IP family, preventing invalidation issues before they affect DNS lookups.
Solution Approach 2:
The system implements a feedback mechanism that monitors network interface changes and IP family transitions. When a change is detected, the system feeds this information back to the DNS cache management module, which then validates and updates cache entries accordingly, ensuring continuous reliability while maintaining efficiency.
2Reliability
If DNS cache is flushed on every network transition, then cache validity is maintained, but lookup performance deteriorates due to increased DNS requests
Solution Approach 1:
The system applies local quality by treating different network transitions differently based on IP family compatibility. Instead of a blanket flush policy, the system selectively validates and updates only those cache entries that are affected by the specific network transition type, maintaining validity where needed while preserving performance by avoiding unnecessary flushes.
Solution Approach 2:
The system changes the validation parameter from a binary flush-or-not approach to a nuanced IP family compatibility check. By monitoring the IP family parameter of the new network and comparing it with cached entries, the system dynamically adjusts cache management behavior, flushing only when parameters indicate incompatibility.
3Reliability
If IP address format compatibility is enforced, then network communication reliability is improved, but adaptability to different IP families deteriorates
Solution Approach 1:
The system implements dynamic adaptability by adjusting its IP family handling behavior based on the current network environment. When transitioning to a new IP family, the system dynamically updates its cache validation rules and IP address format expectations, allowing it to reliably communicate across different IP families (IPv4, IPv6, dual-stack) without sacrificing adaptability.
Data Source
AI summary
Described embodiments provide systems and methods for invalidating a cache of a domain name system (DNS) information based on changes in internet protocol (IP) families. A mobile device having one or more network interfaces configured to communicate over a plurality of networks using a plurality of internet protocol (IP) families is configured to maintain a cache storing DNS information of one or more IP addresses of a first IP family of the plurality of IP families used by the mobile device for a connection to a first network of the plurality of networks. The device can detect a change in the connection of the mobile device from the first network using the first IP family to a second network using a second IP family different from the first IP family and flush at least the DNS information of one or more IP addresses of the first IP family from the cache to prevent use by the mobile device of an IP address that corresponds to an invalid cache entry.