TCP Reset Packet Flow Termination for SDN Hardware Accelerators
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Solution Overview
Problem
Inefficient flow termination in SDN systems leads to resource wastage due to endpoints continuously checking on terminated flows, causing unnecessary resource tie-up and latency issues.
Innovation Solution
A hardware accelerator in SDN systems generates TCP reset packets to notify endpoints of flow termination, reducing computational burden and latency by using a software-based reset packet generator to create these packets, thus allowing endpoints to release resources promptly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If flow termination is performed without endpoint notification, then resource cleanup at the SDN device is achieved, but endpoints continue to waste resources by continuously checking terminated flows
Solution Approach 1:
The patent introduces TCP reset packets as an intermediary notification mechanism. When the SDN device terminates a flow, it sends TCP reset packets to the endpoint devices to notify them of the termination. This intermediary notification allows endpoints to promptly release resources without continuously checking, thereby reducing resource wastage while maintaining a manageable system complexity through standardized protocol usage
2Loss of time
If endpoints are notified of flow termination, then resource release time is reduced, but additional packets and processing are required
Solution Approach 1:
The patent leverages the existing TCP protocol mechanisms and endpoint's own TCP stack to handle flow termination notification. By using standard TCP reset packets that endpoints are already equipped to process, the system achieves rapid resource release without requiring additional specialized packets or processing logic beyond what the TCP protocol already provides
3Speed
If hardware accelerators generate TCP reset packets directly, then latency is reduced, but computational burden on the accelerator increases
Solution Approach 1:
The patent extracts the TCP reset packet generation function from the hardware accelerator and places it in the software control plane. The hardware accelerator maintains flow state information and triggers flow termination, while the software component generates and sends the TCP reset packets. This separation allows the hardware accelerator to focus on high-speed flow management without the computational overhead of packet generation, achieving both speed and efficiency
Data Source
AI summary
A method of forcefully terminating a flow includes identifying, by a hardware accelerator, a flow entry in a flow table corresponding to a flow determined to satisfy predefined criteria for flow termination and transmitting, by the hardware accelerator, a flow termination request to a software-based reset packet generator. The flow termination request includes flow match characteristics included in the flow entry of the flow table. The method further includes generating, at the software-based reset packet generator, a first transport control protocol (TCP) reset packet with header information matching the flow match characteristics and transmitting the first TCP reset packet to the hardware accelerator. The method still further provides for transforming the first TCP reset packet, at the hardware accelerator, according to a first transformation defined in the flow entry. The transformed TCP reset packet is transmitted to the destination device and the flow entry is deleted from the flow table.