SDN Switch NAT Offload for Latency Reduction
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Solution Overview
Problem
Conventional Software Defined Networking (SDN) networks experience increased packet processing latency due to the necessity of all subscriber flows traversing a Network Address Translation (NAT) device, which introduces additional latency from buffering and copying packets at both the NAT device and switches, exacerbated by virtualization which adds further latency.
Innovation Solution
A method is implemented where the control plane device configures the data plane device in an SDN network to perform network address translation (NAT) for a flow, allowing it to bypass the NAT device, thereby reducing latency by steering the flow to perform NAT at the switch instead of the NAT device and disabling timeout processing to prevent premature resource release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all subscriber flows traverse a NAT device for network address translation, then NAT service is provided, but packet processing latency increases due to buffering and copying packets at the NAT device and switches
Solution Approach 1:
The patent segments the NAT processing function from the traditional NAT device and relocates it to the SDN controller. The SDN controller maintains translation rules and performs NAT operations centrally, while data plane devices (switches) forward packets without traversing the NAT device. This segmentation allows NAT service to continue while eliminating the latency caused by packet traversal through the NAT device and intermediate switches.
Solution Approach 2:
The SDN controller acts as an intermediary between the NAT device and data plane devices. It receives translation rules from the NAT device, configures flow steering rules in data plane devices to bypass the NAT device, and coordinates the NAT bypass operation. This intermediary role enables the system to maintain NAT functionality while optimizing the packet path to reduce latency.
2Loss of time
If flows are steered to bypass the NAT device and perform NAT at the switch, then latency is reduced, but device complexity increases due to additional configuration and coordination
Solution Approach 1:
The data plane device (switch) is configured to perform NAT operations autonomously based on translation rules received from the SDN controller. Once the SDN controller installs the translation rule and flow steering rule in the switch, the switch independently performs NAT and forwarding operations without requiring continuous coordination or complex configuration. This self-service approach reduces operational complexity while maintaining the latency benefits.
3Loss of energy
If NAT processing is offloaded from the NAT device to the data plane device, then bandwidth consumption decreases, but reliability may be affected due to timeout processing issues
Solution Approach 1:
The SDN controller implements feedback mechanisms to monitor flow status and coordinate between the NAT device and data plane devices. When a flow is steered to bypass the NAT device, the SDN controller tracks the flow and ensures timeout processing is properly handled. This feedback loop maintains connection reliability by preventing premature resource release while enabling bandwidth efficiency through NAT offloading.
Data Source
AI summary
A method is implemented by a control plane device in a Software Defined Networking (SDN) network to configure a data plane device in the SDN network to perform network address translation (NAT) for a flow so that the flow can bypass a NAT device. The method includes receiving a translation rule for the flow from the NAT device, configuring the data plane device to steer the flow such that the flow bypasses the NAT device, configuring the data plane device to perform NAT for the flow according to the translation rule for the flow, and transmitting an indication to the NAT device that the flow is to bypass the NAT device.