TCP Segmentation Offload Using Underlay MSS in Overlay Networks
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Solution Overview
Problem
Traditional TCP segmentation offload (TSO) methods face limitations in overlay networks due to the use of a smaller maximum segment size based on the limitations of the overlay network, leading to increased processing requirements for physical switches and receiver NICs, and inefficient data transmission.
Innovation Solution
A method that dynamically adjusts the TCP maximum segment size based on the underlying physical network, optimizing data transmission by determining a modified maximum segment size that aligns with the physical network's capabilities and maintaining transparency to virtual machines, allowing for efficient segmentation and transmission of large data packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional TSO uses a smaller MSS based on overlay network limitations, then compatibility with overlay network is maintained, but data transmission efficiency deteriorates due to generation of large number of small packets
Solution Approach 1:
The patent implements dynamic MSS adjustment by introducing a modified MSS parameter that adapts to the physical network's MTU capabilities. The system dynamically determines whether to use the traditional overlay-based MSS or a larger physical-network-optimized MSS based on packet size thresholds and network conditions, allowing flexible adaptation between different network layers without fixed constraints.
Solution Approach 2:
The patent changes the MSS parameter from a fixed value based on overlay network limitations to a dynamic parameter that can be adjusted based on physical network capabilities. By introducing a modified MSS that accounts for physical network MTU while maintaining overlay compatibility, the system optimizes packet size to reduce the number of packets generated during TSO, thereby improving transmission efficiency.
2Reliability
If traditional TSO segments data based on overlay network MSS, then overlay network constraints are satisfied, but processing overhead increases for physical switches and receiver NICs
Solution Approach 1:
The patent performs preliminary segmentation at the source using the modified MSS before transmission over the physical network. By pre-segmenting large packets into appropriately sized segments that match physical network capabilities, the system reduces the processing burden on physical switches and receiver NICs, as they receive already-optimized packets rather than having to handle oversized packets requiring additional segmentation.
Solution Approach 2:
The patent introduces a modified MSS parameter as an intermediary between overlay network requirements and physical network capabilities. This intermediate parameter allows the system to bridge the gap between virtualized overlay constraints and physical network realities, enabling efficient segmentation that satisfies both layers without requiring complex processing at intermediate network devices.
3Adaptability or versatility
If TSO generates many small packets to comply with overlay MSS, then overlay network compatibility is maintained, but network performance deteriorates due to increased packet processing requirements
Solution Approach 1:
The patent optimizes network performance by changing the packet size parameter through modified MSS calculation. Instead of using the conservative overlay-based MSS that generates many small packets, the system calculates a modified MSS that leverages the physical network's larger MTU capability, resulting in fewer, larger packets that reduce processing overhead and improve overall network throughput while maintaining overlay compatibility through proper encapsulation.
Data Source
AI summary
Examples described herein include efficient data packet transmission between virtual machines (“VMs”) on different hosts. An example method includes generating a large data packet at a source VM and determining a modified maximum segment size for efficient transmission. This modified size replaces the default maximum segment size through a TSO MSS override. Segmentation occurs based on the modified size, and the data segments are transmitted to the destination VM, even if on a different host. Dynamic determination of the modified size optimizes data transmission efficiency and network performance. It accounts for network headers and enables efficient transmission with or without large receiving offload (“LRO”) support. Additionally, non-transitory computer-readable media and servers implementing the method are disclosed. These systems and methods achieve streamlined data transmission, improving network performance and reducing processing overhead.