SDN Control Plane Bandwidth Adaptation via TCP Options
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Solution Overview
Problem
Current bandwidth allocation for control plane communications in software-defined networks (SDNs) does not consider network conditions, leading to potential overload and inefficient use of bandwidth, as it simply pushes data without accounting for available link bandwidth or congestion.
Innovation Solution
The method involves using TCP options to dynamically adjust bandwidth allocation between SDN controllers and network devices by comparing the indicated bandwidth in TCP packets with the actual outgoing link bandwidth, updating the TCP options field if necessary, and using the maximum end-to-end bandwidth to determine the amount of control data that can be sent without monopolizing the link, while also indicating congestion to adjust the control plane rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the SDN controller pushes as much data across the control channel as possible, then the quantity of control plane information transmitted is increased, but network congestion and bandwidth overload occur
Solution Approach 1:
The patent implements dynamic bandwidth adjustment by having network elements compare the bandwidth value in TCP options with their outgoing link bandwidth and update the TCP options field accordingly. This dynamic adaptation allows the control plane to adjust its data transmission rate based on real-time network conditions, preventing congestion while maximizing information flow when bandwidth is available.
Solution Approach 2:
The patent establishes a feedback mechanism where network elements monitor their outgoing link bandwidth and feed this information back by updating the TCP options field in transmitted packets. The SDN controller receives this feedback and adjusts its data push rate accordingly, creating a closed-loop control system that prevents network overload while maintaining optimal control plane communication.
2Quantity of substance
If the SDN controller requests monitoring data from network devices, then the quantity of control plane information is increased, but the available bandwidth for data traffic may be insufficient
Solution Approach 1:
The patent changes the bandwidth parameter dynamically by comparing the requested bandwidth with actual outgoing link bandwidth at each network element. When the control plane requests more bandwidth than available, the network elements update the TCP options field to reflect the reduced bandwidth, thereby adjusting the control data transmission rate to prevent starvation of data traffic while still allowing essential control plane communication.
3Ease of operation
If bandwidth allocation does not consider network conditions, then the ease of operation is improved, but network overload and inefficient bandwidth use occur
Solution Approach 1:
The patent implements self-service by enabling network elements to automatically adjust bandwidth allocation without manual intervention. Each network element autonomously compares the bandwidth value in TCP options with its outgoing link bandwidth and updates the TCP options field as needed, allowing the system to self-regulate bandwidth usage based on actual network conditions while maintaining operational simplicity for the controller.
Data Source
AI summary
A method is described that includes receiving at a network element a transmission control protocol (“TCP”) packet with TCP options set on a link between a controller and a destination node. If the network element comprises a transit node, the method includes comparing a bandwidth value indicated in a TCP options field of the received TCP packet with an outgoing link bandwidth of the network element. If the bandwidth value indicated in the TCP options field is greater than the outgoing link bandwidth of the network element, the method includes updating the bandwidth value in the TCP options field to be equal to the outgoing link bandwidth of the network element, and forwarding the packet to a next network element. If the bandwidth value indicated in the TCP options field is not greater than the outgoing link bandwidth, the bandwidth value in the TCP options field is not changed.