Reverse Path PMTU Discovery Mechanism
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Solution Overview
Problem
Existing PMTU discovery methods in communications networks are inefficient due to reliance on cooperative intermediate devices and require multiple packet round trips, leading to packet fragmentation, increased overhead, and reduced network performance.
Innovation Solution
Implementing reverse PMTU discovery, where the destination device estimates the PMTU based on received fragments and informs the source device to size packets accordingly, reducing the need for 'Fragmentation Needed' messages and minimizing fragmentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional PMTU discovery methods are used, then packet transmission can occur, but packet fragmentation increases and network performance decreases
Solution Approach 1:
The patent inverts the traditional PMTU discovery approach by having the destination device determine the PMTU and communicate it back to the source device, rather than having the source device discover PMTU through intermediate devices. This reverse approach eliminates reliance on cooperative intermediate devices and reduces packet fragmentation by enabling the source to send optimally sized packets from the outset.
2Quantity of substance
If packet fragmentation is used, then large data can be transmitted, but processing overhead increases and network resources are wasted
Solution Approach 1:
The patent applies preliminary action by having the destination device determine and communicate the PMTU to the source device before data transmission begins. This allows the source device to pre-calculate optimal packet sizes and send appropriately sized packets from the start, eliminating the need for fragmentation and the associated processing overhead for fragmenting and reassembling packets.
3Measurement precision
If multiple packet round trips are required for PMTU discovery, then PMTU can be determined, but transmission time increases
Solution Approach 1:
The patent inverts the traditional multi-round-trip PMTU discovery process by having the destination device determine the PMTU and send it back to the source in a single communication exchange. This reverse approach reduces the discovery time from multiple round trips to a single interaction, while maintaining accurate PMTU determination.
4Measurement precision
If intermediate devices are required for PMTU discovery, then PMTU can be discovered, but system complexity increases
Solution Approach 1:
The patent extracts the PMTU determination function from intermediate devices and concentrates it at the destination device. This eliminates the need for intermediate devices to cooperate in PMTU discovery, simplifying the system by removing dependencies on intermediate device functionality and reducing overall system complexity.
Data Source
AI summary
An example method is provided for a first device to perform reverse path maximum transmission unit (PMTU) discovery in a communications network. The method may comprise receiving multiple fragments of a packet sent by a second device via a path from the second device to the first device in the communications network. Based on the received fragments, a reverse PMTU that represents an estimate of a PMTU of the path from the second device to the first device may be determined. The method may further comprise configuring a message that includes data relating to the reverse PMTU and sending, to the second device, the message to inform the second device to size packets for transmission from the second device to the first device based on the data relating to the reverse PMTU.