DNS Server Selection via ANDSF Inter System Routing Policies
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Solution Overview
Problem
Devices with multiple interfaces connected to different networks face challenges in selecting the appropriate DNS server for domain name resolution, leading to potential communication failures and scalability issues due to contradictory global configuration information and limitations in DHCP message size.
Innovation Solution
Implementing Inter System Routing Policies (ISRPs) associated with Access Network Discovery and Selection Function (ANDSF) to manage DNS server selection by routing DNS queries based on domain name query content, using ISRP management objects that include routing rules specifying the appropriate DNS server and interface for resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a host device uses multiple interfaces connected to different networks, then the device can access more networks and resources, but the device cannot determine which DNS server to use for resolving domain names, leading to communication failures
Solution Approach 1:
The patent introduces an intermediary mechanism (DNS query interception and routing function) that sits between the application and DNS servers. This intermediary captures DNS queries, determines the appropriate network interface based on routing policies, and forwards queries to the correct DNS server. This resolves the contradiction by enabling reliable DNS resolution across multiple networks without requiring the application to make complex routing decisions.
Solution Approach 2:
The system implements feedback mechanisms where routing policies are dynamically adjusted based on network conditions, interface availability, and resolution success. The device monitors which interfaces are active and configures routing rules accordingly, creating a closed-loop system that adapts to changing network environments while maintaining reliable DNS resolution.
2Extent of automation
If DHCP message size is used to carry DNS server information, then configuration can be automated, but the message size limits the number of domains and networks that can be carried
Solution Approach 1:
The patent segments the DNS configuration information into multiple routing policy objects, each associated with specific networks and domains. Instead of attempting to carry all DNS server information in a single DHCP message, the system divides the configuration into manageable segments that can be distributed across multiple messages or obtained through alternative mechanisms. This allows the system to support a much larger number of domains and networks than the DHCP message size would permit in a single message.
3Ease of manufacture
If traditional networking stacks are used in multi-interface hosts, then implementation is straightforward, but contradictory global configuration information causes communication failures
Solution Approach 1:
The patent implements preliminary action by pre-configuring routing policies and DNS server associations before actual DNS queries are made. The system establishes routing rules that map specific domains and networks to appropriate DNS servers in advance, so when DNS queries need to be resolved, the correct server can be selected immediately without complex real-time decision-making. This preliminary setup prevents communication failures while maintaining implementation simplicity.
Data Source
AI summary
Systems and methods for extending Inter System Routing Policies (ISRPs) of an ANDSF to enable domain name system (DNS) flows to be identified by a queried domain may be disclosed. Such systems and methods may include providing an ISRP with a routing rule that may be used to select a DNS sever or interface thereof and resolve DNS for a target domain name and/or corresponding target URL for a website.