Forwarding Element Local ARP Processing in SDN
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Solution Overview
Problem
Software-defined networks (SDNs) face challenges in efficiently handling end-host generated control protocols like ARP, which cause significant traffic and cannot be effectively integrated with legacy control methods, leading to increased interactions between controllers and forwarding elements.
Innovation Solution
Implementing packet processing rules for end-host control protocols on forwarding elements, allowing them to process and respond to ARP requests locally based on extracted information, while maintaining a database of network locations and updating it, thereby reducing traffic and interactions with the controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If end-host control protocols like ARP are handled by relaying to the SDN controller, then centralized control is maintained, but network traffic volume increases significantly and controller burden increases
Solution Approach 1:
The patent segments the control protocol handling by introducing intermediate forwarding elements (switches, routers) that locally process ECP packets using distributed databases. This divides the centralized controller's workload into distributed processing units, reducing the volume of packets that must traverse to the controller while maintaining centralized coordination through periodic database updates.
Solution Approach 2:
The patent introduces forwarding elements as intermediaries between end hosts and the SDN controller. These intermediaries maintain local copies of ECP databases and handle protocol packets locally, acting as mediators that reduce direct communication between end hosts and the controller, thereby reducing network traffic volume to the controller.
2Productivity
If packet processing rules for ECP are installed on forwarding elements, then local processing capability is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-installing packet processing rules and ECP database information on forwarding elements before they are needed for actual packet handling. This allows forwarding elements to immediately process ECP packets locally without requiring complex real-time decision-making logic, simplifying their operational complexity while maintaining high processing capability.
3Quantity of substance
If ECP packets are processed locally by forwarding elements, then traffic to controller is reduced, but consistency of control information may deteriorate
Solution Approach 1:
The patent implements feedback mechanisms where forwarding elements periodically update the SDN controller with changes in their local ECP database states. This feedback loop ensures that the centralized controller maintains an accurate view of the network state while forwarding elements can operate autonomously using their local cached information, thus reducing traffic to the controller while maintaining control information consistency.
Data Source
AI summary
A method for controlling a network. The network includes a plurality of forwarding elements (FE) connected with each other, one or more end hosts (EH) connected to one or more of the FE, and a controller for controlling the FE. The method includes installing packet processing rules for end-host control protocols (ECP) on the FE. When an ECP Request (ECPRQ) is received by an FE and the ECPRQ was not processed by the controller, the ECPRQ is provided to the controller and an ECP response is computed by the receiving FE based on extracted information from the ECPRQ mapped onto forwarding information based on mapping information if provided, otherwise if the ECPRQ was processed by the controller, the ECPRQ is forwarded according to forwarding information of the ECPRQ. When an ECP response (ECPR) is received by an FE, the ECPR is forwarded according to forwarding information.