Differentiated MPTCP Route Advertisement for Non-Overlapping Subflows
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Solution Overview
Problem
In switched networks, multipath TCP connections can lose resilience and throughput if subflows are routed along the same path, leading to network failures and reduced reliability.
Innovation Solution
Networking devices to which a computing device is multihomed advertise their primary IP addresses for different subflows of a multipath TCP connection to ensure non-overlapping routes, enhancing redundancy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If subflows are routed along the same path in the switched network, then routing simplicity is maintained, but network resilience and reliability deteriorate
Solution Approach 1:
The patent applies local quality by making routing behavior dependent on the specific subflow characteristics. Different subflows of the same MPTCP connection are assigned different routing behaviors: the first subflow uses default routing while subsequent subflows use differentiated routing through alternative nexthops. This localized differentiation ensures that each subflow contributes to overall network resilience without requiring complete reconfiguration of the entire routing system.
Solution Approach 2:
The patent implements preliminary action by pre-configuring multiple nexthop addresses in the forwarding information base (FIB) before subflows are established. The networking devices maintain a pool of alternative nexthops ready for assignment, so when subsequent subflows need differentiated routing, the alternative paths are already prepared and can be assigned immediately without dynamic route computation, thus maintaining routing simplicity while ensuring resilience.
2Reliability
If differentiated routing is implemented for subflows, then network reliability improves, but routing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the routing advertisement process into distinct segments for different subflows. The first subflow receives standard routing advertisements, while subsequent subflows receive differentiated advertisements with alternative nexthop addresses. This segmentation allows the system to implement complex differentiated routing only where needed (for subsequent subflows) while keeping the majority of routing simple, thus improving connection resilience without proportionally increasing overall system complexity.
Solution Approach 2:
The patent uses copying by creating alternative copies of routing information for subsequent subflows. Instead of computing entirely new routes, the system copies existing routing entries and modifies them to use alternative nexthop addresses from the pre-configured FIB pool. This copying approach ensures that differentiated routing information is readily available without requiring complex real-time route computation, thereby improving reliability while limiting the increase in routing complexity.
3Adaptability or versatility
If multiple nexthop addresses are maintained in FIB, then route differentiation capability improves, but memory requirements increase
Solution Approach 1:
The patent applies partial action by maintaining multiple nexthop addresses in the FIB only for specific prefixes that require differentiated routing for MPTCP connections. Not all routing entries in the network need alternative nexthops - only those relevant to the multihomed computing devices establishing MPTCP connections. This selective approach provides route differentiation capability where needed while avoiding the memory overhead of maintaining excessive alternative routes throughout the entire network, thus balancing adaptability with memory efficiency.
Data Source
AI summary
In one embodiment, a method comprises determining, by a first networking device, that a first subflow of a multipath transmission control protocol (MPTCP) connection has been established between a first internet protocol (IP) address of a first computing device and an IP address of a second computing device, wherein the first computing device is multihomed to the first networking device and a second networking device. The method also includes determining, by the first or second networking device, a request to establish a second subflow of the MPTCP connection between a second IP address of the first computing and the IP address of the second computing device. In addition, the method includes advertising, by the first networking device, a primary IP address (PIP) of the first networking device for the first subflow and advertising, by the second networking device, a PIP of the second networking device for the second subflow.