IPv4-in-IPv6 Relaying for Stable TCP Across Network Switching
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Solution Overview
Problem
Existing Internet-connected devices experience disruptive connection disruptions and delays when switching between different networks due to the need to restart Transmission Control Protocol (TCP) connections, as they maintain different IP addresses on each network.
Innovation Solution
Implementing IPv4-in-IPv6 relaying mechanisms in routers to preserve a single IPv4 public address across multiple connections, using techniques like MAP-E and MAP-T to ensure seamless transitions without disrupting TCP sessions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a device uses different IP addresses on different network connections, then each connection can be independently configured and managed, but switching between connections causes TCP connection disruptions and requires connection restart
Solution Approach 1:
The patent introduces a border router as an intermediary that performs IPv4-in-IPv6 translation and address mapping. The border router maintains a mapping between the device's IPv6 addresses on different connections and a single IPv4 address, acting as a mediator that allows the device to switch connections without changing its apparent IPv4 address to external hosts, thus maintaining TCP connection stability while enabling network flexibility
Solution Approach 2:
The patent segments the IP addressing function into two parts: the device uses different IPv6 addresses on different connections for independent configuration, while the border router maintains a unified IPv4 address mapping for external communication. This segmentation allows each connection to be independently managed while preserving overall connection stability
2Adaptability or versatility
If IPv4 public addresses are allocated to each device on each network connection, then each connection has its own address, but IPv4 address scarcity is exacerbated
Solution Approach 1:
The patent makes a single IPv4 public address serve multiple functions by allowing it to be mapped to different IPv6 addresses on different network connections. The border router maintains mappings that allow the same IPv4 address to represent the device regardless of which connection is active, enabling one IPv4 address to serve multiple connection scenarios and reducing overall IPv4 address consumption
Solution Approach 2:
The patent implements IPv4-in-IPv6 tunneling where IPv4 packets are nested within IPv6 packets. The device's traffic is encapsulated in IPv6 on the local connection, then translated at the border router to use a shared IPv4 address for external communication. This nesting allows efficient use of IPv4 addresses while maintaining connection independence
Data Source
AI summary
A method, implemented in a router in a Communication Service Provider (CSP) network, includes connecting to a device via at least two connections where a first connection includes a first Wide Area Network (WAN) interface and a second connection includes a second WAN interface; receiving an encapsulated packet from one of the at least two connections where the encapsulated packet is destined for an Internet Protocol version 4 (IPv4) address on the Internet; and creating an IPv4 packet from the encapsulated packet by de-encapsulating the encapsulated packet and including an IPv4 public address in an IPv4 packet, wherein the IPv4 public address is associated with the router.