SDN Network Controller Delay Measurement via Probe Packets
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Solution Overview
Problem
Current methods for measuring network delay in SDN are inefficient, as they either consume significant network resources or require complex frameworks and precise timing synchronization, failing to accurately measure each link delay for precise network improvement.
Innovation Solution
A network controller with modules for initialization, head measurement, regular measurement, and delay calculation that uses probe packets to measure echo-response and transport delays between network switches, calculating hop and total nodal delays without altering the existing network equipment or framework.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active delay measurement technique is used to measure each link delay, then measurement precision is improved, but network resource consumption increases significantly
Solution Approach 1:
The patent introduces a network controller as an intermediary that centralizes the delay measurement function. Instead of each network switch independently measuring delays (which consumes network resources), the controller orchestrates probe packet injection and collects timing information from switches, thereby achieving precise link delay measurement while reducing overall network resource consumption.
Solution Approach 2:
The patent uses probe packets as simplified copies of actual data packets to measure delay characteristics. These probe packets replicate the essential forwarding behavior of real traffic without carrying actual payload data, enabling delay measurement while minimizing network resource consumption compared to using real traffic for measurement.
2Loss of energy
If passive delay measurement technique is used to measure link delay, then network resource consumption is reduced, but measurement precision deteriorates due to difficulty in identifying packets under detection
Solution Approach 1:
The network controller acts as an intermediary that enables passive measurement to achieve active measurement precision. The controller injects probe packets and collects detailed timing information from each switch's ingress and egress ports, effectively transforming passive measurement into a controlled measurement process that achieves high precision without requiring modifications to network switch hardware.
Solution Approach 2:
The patent uses distinctive probe packets with identifiable characteristics (such as specific Ethernet types or TTL values) that stand out from normal traffic, enabling precise identification of measurement packets at each switch without requiring complex packet inspection. This is analogous to using a distinctive color to track a specific object in a crowd.
3Measurement precision
If passive delay measurement technique with central management system is implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The network controller performs multiple functions: it manages OpenFlow flow tables for packet forwarding, collects statistics from switches, and conducts delay measurements. By consolidating these functions in a single controller, the patent avoids the complexity of distributed measurement systems while achieving high measurement precision through centralized coordination.
4Measurement precision
If active delay measurement technique is used, then measurement precision is improved, but timing synchronization requirements become more stringent
Solution Approach 1:
The network controller serves as a centralized timing reference that eliminates the need for complex distributed synchronization between switches. All timing measurements are referenced to the controller's clock, and the controller collects and processes timing information from switches, thereby achieving high measurement precision without requiring precise synchronization between network switches themselves.
Data Source
AI summary
A network controller for delay measurement in SDN and related delay measurement system and delay measurement method are provided. A probe packet is used to record the transmission of the probe packet between the network controller and network switches, to calculate a transport delay time between the network switches and hop delay time between the network switches, to obtain the delay of each link in the transmission path, which helps in finding out a critical hop in the SDN transmission path. Through the delay measurement mechanism according to the present disclosure, the critical hop will become a reference based on which a network manager adjusts a network framework, or a basis taken by an SDN control system to select a path.