Interface Selection for IP Packets with Address Conflicts
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Solution Overview
Problem
In managed IP devices, address conflicts arise when unmanaged and managed DHCP servers assign the same IP address to different devices on their respective networks, leading to communication failures between local area networks and the Internet, as conventional systems can only assign a single default gateway to the routing table, discarding the other and causing communication with subnets behind the discarded gateway to be impossible.
Innovation Solution
The solution involves selecting the appropriate network interface and routing table based on the source IP address of packets, using standard socket APIs to specify the correct interface and routing table, even when address conflicts exist, allowing communication with devices on both local and wide area networks by defining multiple routing tables and configuring the routing policy database to select the correct table based on the source address.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple DHCP servers assign IP addresses on separate networks, then address coverage is improved, but address conflicts occur when the same IP address is assigned to different devices
Solution Approach 1:
The patent segments the routing table into multiple separate routing tables, each associated with a specific network interface and DHCP server. This allows each routing table to manage IP addresses independently without conflicts, while the system as a whole maintains comprehensive address coverage across multiple networks.
Solution Approach 2:
The patent introduces an intermediary mechanism (multiple routing tables with selective application) that mediates between multiple DHCP servers assigning IP addresses. This intermediary layer prevents direct conflicts by ensuring that IP address assignments from different DHCP servers are managed in separate routing contexts.
2Device complexity
If a single default gateway is assigned to the routing table, then system simplicity is maintained, but communication with subnets behind the discarded gateway becomes impossible
Solution Approach 1:
The patent divides the single routing table into multiple routing tables, each handling specific subnets and gateways. This segmentation allows the system to maintain simplicity within each routing table while achieving comprehensive communication capability across all subnets through the collective set of routing tables.
Solution Approach 2:
The patent implements dynamic selection of routing tables based on the source IP address of packets. The system dynamically determines which routing table to use, allowing flexible adaptation to different communication scenarios while maintaining operational simplicity through automated selection logic.
3Ease of operation
If conventional routing tables are used with single default gateway, then configuration ease is maintained, but communication failures occur between LAN and Internet
Solution Approach 1:
The patent segments routing functionality into multiple routing tables that can be independently configured for different networks. This segmentation maintains configuration ease by allowing simple, focused configuration for each network while ensuring reliable communication across all networks through the coordinated use of multiple routing tables.
Data Source
AI summary
An interface may be selected. First, it may be determined that an application is intended to use a first one of a plurality of network interfaces. Next, a first one of a plurality of routing tables may be selected corresponding to the determined first one of the plurality of network interfaces. Then the selected first one of the plurality of routing tables may be used to communicate with a first device on a first network over the determined first one of the plurality of network interfaces.