Gateway MTU Synchronization in VPN Tunnel Negotiation
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Solution Overview
Problem
Current path maximum transmission unit discovery (PMTUD) methods in computer networks often lead to data packet fragmentation and dropping due to mismatched MTU values between IP hosts, especially in VPN environments, resulting in inefficiencies and increased latency.
Innovation Solution
A method for synchronizing path maximum transmission unit (MTU) values between gateways through tunnel negotiations, where initial MTU values are established and updated dynamically to ensure data packets are not dropped during transmission, using protocols like IKE and IKEv2 for peer notification and MTU adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If path MTU discovery is performed using traditional methods in VPN environments, then data packets may be transmitted, but data packet fragmentation and dropping occur due to mismatched MTU values between IP hosts
Solution Approach 1:
The patent performs MTU discovery during tunnel negotiation phase, before actual data transmission begins. This preliminary action establishes synchronized MTU values between VPN gateways in advance, preventing packet fragmentation and dropping during data transmission without requiring complex runtime MTU synchronization mechanisms
Solution Approach 2:
The patent implements a feedback mechanism where VPN gateways exchange MTU capability information during tunnel negotiation and update each other on MTU changes. This feedback loop ensures both gateways maintain consistent MTU values, resolving the reliability issue caused by MTU mismatches while keeping the synchronization process manageable through structured information exchange
2Productivity
If large MTU values are used to improve transmission efficiency, then fewer data packets are transmitted, but network latency increases and packet errors become more likely
Solution Approach 1:
The patent dynamically determines the optimal MTU value by evaluating network path characteristics and gateway capabilities during tunnel negotiation. Instead of using fixed or arbitrarily large MTU values, the system adjusts the MTU parameter to match the actual path capacity, achieving high transmission efficiency without excessive latency or error rates
3Adaptability or versatility
If IP fragmentation is used to transmit packets larger than path MTU, then data can be transmitted through the network, but packets are dropped and retransmitted multiple times, impacting network quality
Solution Approach 1:
The patent determines the appropriate packet size through MTU discovery during tunnel negotiation, before data transmission begins. This preliminary sizing action ensures packets are configured to fit the network path capacity, eliminating the need for fragmentation and subsequent retransmissions that would compromise delivery reliability
Solution Approach 2:
The patent prevents fragmentation issues by establishing correct MTU values in advance through gateway negotiations. This preliminary anti-action counteracts potential fragmentation problems before they occur, ensuring packets are sized appropriately for the network path and avoiding the harmful effects of fragmentation and retransmission
Data Source
AI summary
Methods are directed towards initializing a path maximum transmission unit value for two gateways in communication via a network tunnel (e.g., VPN environment). The initialized path maximum transmission unit value is used in establishing the network tunnel of the two gateways. Methods are also directed towards synchronizing path maximum transmission unit values for the two gateways after the network tunnel has been established. These methods minimize the occurrence of dropped data packets arising from mismatched path maximum transmission unit value between the gateways.