Network Element Overload Signaling for SDN Reliability
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Solution Overview
Problem
In data transfer networks, especially software-defined networks, network elements can become overloaded, leading to impaired reaction to control-plane messages, causing other elements to mistakenly deem them non-functional and resulting in inefficient network re-routing.
Innovation Solution
A network element and a controller system that send overload messages to indicate temporary impairment, allowing the network to reconfigure and reduce the number of neighbors for an overloaded element, maintaining data forwarding capabilities and restoring normal operations once the overload is resolved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control section processes all control-plane messages during overload, then complete control functionality is maintained, but reaction time to control-plane messages deteriorates
Solution Approach 1:
The patent extracts the overload indication function from the normal control-plane message processing. When overload is detected, the network element sends a specific overload indication message to inform neighbors of its impaired state, separating the overload management function from regular control-plane operations.
Solution Approach 2:
The patent implements preliminary action by proactively sending overload indication messages before the network element completely fails to respond. This allows neighbors to take preventive measures (such as adjusting routing or reducing control-plane traffic) before the overload becomes critical.
2Reliability
If other network elements bypass the overloaded element, then network reliability is maintained, but network capacity is wasted
Solution Approach 1:
The patent implements feedback by sending overload indication messages from the overloaded network element to its neighbors. This feedback mechanism allows neighbors to understand the element's actual state (overloaded but functional) and make informed decisions about whether to bypass it or maintain routing through it.
Solution Approach 2:
The overload indication message acts as an intermediary communication that bridges the gap between the overloaded element's actual capability and its impaired response behavior. It provides intermediate information that allows neighbors to adjust their behavior appropriately without completely bypassing the element.
3Productivity
If the network element sends overload messages, then unnecessary reconfiguration is prevented, but additional control-plane traffic is generated
Solution Approach 1:
The patent applies partial action by sending overload indication messages selectively - only when actual overload conditions are detected, not continuously. This partial communication approach provides sufficient information to prevent unnecessary reconfiguration without generating excessive control-plane traffic.
Data Source
AI summary
A network element includes a data transfer interface for connecting to a data transfer network, a data-plane section for managing data to be forwarded, and a control section for configuring the data-plane section in accordance with configuration data carried by control-plane messages received from the data transfer network. The control section controls the data transfer interface to send one or more overload messages to the data transfer network in response to an overload situation where the workload of the control section impairs the ability of the control section to react to the control-plane messages. Thus, other network elements know that the network element that does not respond to the control-plane messages and thus appears to be non-working may still forward data even though its ability to react to the control-plane messages is, at least temporarily, impaired.