SDN Flow Table Update Scheduling to Reduce Controller Load
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Solution Overview
Problem
In Software Defined Networking (SDN), updating flow tables in network apparatuses without simultaneous application of flow entries can lead to service disruptions, and existing methods do not efficiently manage the timing of flow table updates, causing inefficiencies and increased load on controllers.
Innovation Solution
A method for updating flow tables in SDN that involves transmitting a flow table modification message with a scheduled time for update, allowing network apparatuses to perform updates at configured times, with options for retransmitting messages upon failure and immediate updating, thereby separating message transmission and update times to control intervals and reduce controller load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flow table modification messages are transmitted to multiple network apparatuses simultaneously, then all apparatuses can be updated at the same time, but it increases controller load and causes service disruptions if any update fails
Solution Approach 1:
The patent segments the simultaneous update process into individual staged updates for each network apparatus. Instead of transmitting all flow table modification messages at once, the controller updates apparatuses sequentially, allowing each update to be isolated and managed independently. This reduces controller load while maintaining reliability through staged progression.
Solution Approach 2:
The patent implements preliminary action by having the controller transmit flow table modification messages with scheduled update times configured in advance. Network apparatuses receive and store these messages, then execute updates at predetermined times rather than immediately, allowing the controller to prepare and distribute updates without bearing the full real-time update load.
2Speed
If flow table updates are performed immediately upon receiving modification messages, then updates are applied quickly, but service disruptions occur when updates are not applied simultaneously across all apparatuses
Solution Approach 1:
The patent uses preliminary action by configuring scheduled update times in advance within flow table modification messages. Network apparatuses receive and store these messages, then execute updates at predetermined times rather than immediately, ensuring simultaneous application across all apparatuses while maintaining quick update execution when the scheduled time arrives.
Solution Approach 2:
The patent implements periodic action through scheduled update mechanisms where flow table modifications are applied at predetermined time intervals across multiple network apparatuses. This ensures that updates propagate systematically through the network in a controlled periodic manner, maintaining service continuity while achieving timely updates.
3Reliability
If flow table modification messages are retransmitted upon update failure, then update reliability is improved, but message transmission time and controller load increase
Solution Approach 1:
The patent implements feedback by having network apparatuses transmit result messages back to the controller indicating whether flow table updates were successful. When a failure is detected, the controller receives this feedback and retransmits the flow table modification message to the affected apparatus, ensuring reliable update delivery while managing retransmission time efficiently.
4Reliability
If scheduled update times are configured differently for different network apparatuses, then service disruptions are minimized, but coordination complexity and controller management increase
Solution Approach 1:
The patent applies local quality by configuring different scheduled update times for different network apparatuses based on their specific roles, locations, or service requirements. Each apparatus receives customized update timing information in its flow table modification messages, allowing localized optimization of update schedules to maintain service availability while reducing the need for complex global coordination.
Data Source
AI summary
Disclosed is a method for updating a flow table for a switch in software defined networking (SDN). The method for updating a flow table of at least one network device by a controller in a software defined network comprises the steps of: transmitting, to at least one network device, a flow table modification message including information on a scheduled time specifying a time at which updating of the flow table is performed; and receiving, from at least one network device, a result message showing an update result on the flow table performed by at least one network device according to the flow table modification message. Accordingly, it is possible to effectively control a load generated on the controller by controlling intervals of updating times between network devices, which is generated during transmission of the flow table modification message to multiple network devices.