VM Checkpointing Quiesce Interface for Network Latency
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Solution Overview
Problem
Current fault-tolerant systems in telecommunications networks face significant latency and resource constraints due to traditional checkpointing methods, making them unfeasible for high-bandwidth environments.
Innovation Solution
A method for checkpointing in a fault-tolerant network device using virtual machines, where a checkpoint engine determines the need for a checkpoint, quiesces the active virtual machine, copies its state, and transfers it to a standby virtual machine, allowing for minimal latency and efficient data replication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional checkpointing methods are used in telecommunications networks, then fault tolerance is achieved, but network latency increases significantly
Solution Approach 1:
The system divides the network device into multiple virtual machines (active VM and standby VM), allowing checkpointing operations to be isolated to specific VM instances rather than disrupting the entire network device. This segmentation enables fault tolerance at the VM level without causing system-wide latency.
Solution Approach 2:
The patent introduces an interface agent as an intermediary component that manages communication between the virtual machines and the external network. This agent handles packet queuing and forwarding during checkpointing operations, preventing direct disruption to network traffic while maintaining fault tolerance capabilities.
2Reliability
If checkpointing operations are performed frequently to maintain fault tolerance, then data consistency is improved, but network performance deteriorates
Solution Approach 1:
The system implements periodic checkpointing where the active virtual machine periodically transfers its state to the standby virtual machine at predetermined intervals. This periodic approach ensures data consistency is maintained while avoiding excessive checkpointing that would degrade network performance. The interface agent manages these periodic transfers efficiently.
3Quantity of substance
If virtual machines are used to perform checkpointing, then resource usage is reduced, but device complexity increases
Solution Approach 1:
The virtual machines serve multiple functions: they act as both the active network processing unit and the checkpoint storage mechanism. The same VM infrastructure that handles network traffic also maintains the checkpoint state, eliminating the need for separate dedicated checkpointing hardware or storage resources.
Solution Approach 2:
The system creates a copy of the active virtual machine's state and transfers it to the standby virtual machine. This copying approach allows the standby VM to assume the active role in case of failure, providing fault tolerance through state replication rather than requiring complex redundant hardware systems.
Data Source
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AI summary
A checkpointing method in a network device fault tolerant system using virtual machines. In one embodiment, the network device has an input port, an output port, an active virtual machine and a standby virtual machine, a network application on the active virtual machine which manipulates data present on the input port and transmits the manipulated data from the output port; a checkpoint engine on the active virtual machine; and an interface agent, on the active virtual machine, having callable functions to move data from the input port to the output port. The method includes the steps of determining, by the checkpoint engine, that a checkpoint is required; requesting by the checkpoint engine that the interface agent quiescent itself; returning, by the interface agent to the network application, an indicator that no packets are available regardless of whether or not packets are arriving at the input port.