Virtual Network Function Migration State Synchronization
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Solution Overview
Problem
Current methods for migrating virtual network functions (VNFs) across nodes in networks often result in packet loss and performance degradation due to redundant traffic and high controller utilization, particularly in scenarios like OpenNF and P2P-based OpenNF, which fail to efficiently manage state transitions during scaling or relocation.
Innovation Solution
A method involving a source node that transmits a snapshot of its virtual network function state and subsequent state update elements to a destination node, allowing the destination node to initialize and update the state without controller intervention, using compact state update byte vectors transmitted via TCP, and signaling to redirect traffic once the state is synchronized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If P2P-based OpenNF duplicates and sends packets to the newly instantiated network function to keep its state up-to-date, then the state synchronization is achieved, but redundant traffic increases significantly and network performance degrades
Solution Approach 1:
The patent extracts only the essential state information from the full packet data and transmits only this extracted state to the destination VNF. This is achieved by identifying and transmitting only the relevant state components (e.g., packet counters, connection tracking information) rather than duplicating entire packet streams, thereby reducing redundant traffic while maintaining state synchronization accuracy.
Solution Approach 2:
The patent applies different transmission strategies to different types of state information. Critical state data that changes frequently is transmitted with higher priority and more frequently, while less critical state information is transmitted less frequently or with lower priority. This localized quality approach optimizes bandwidth usage by matching transmission intensity to the actual importance and volatility of each state component.
2Reliability
If the controller is heavily utilized by data plane tasks such as packet buffering in OpenNF, then packet loss and out-of-order delivery are prevented, but controller overhead increases and system scalability is reduced
Solution Approach 1:
The patent segments the control plane and data plane functions by introducing a state synchronization module that operates independently from the main controller. This segmentation allows the controller to focus on high-level management tasks while the state synchronization module handles packet buffering and state transfer operations, reducing controller overhead and improving system scalability.
Solution Approach 2:
The patent introduces a state synchronization module as an intermediary component between the source and destination VNFs. This intermediary handles the complex tasks of state capture, buffering, and synchronization, preventing these operations from overwhelming the main controller. The module acts as a buffer and mediator, ensuring reliable state transfer without burdening the controller with excessive data plane tasks.
3Productivity
If a snapshot of the VNF state is taken and transmitted to the destination node, then the base state for migration is established, but the state may become outdated due to packets processed since the snapshot
Solution Approach 1:
The patent takes a snapshot of the VNF state in advance as a base for migration, establishing the preliminary state information needed for the destination VNF. This preliminary action enables quick initialization of the destination VNF with the bulk of the state information, while subsequent mechanisms are in place to catch up any missed updates.
Solution Approach 2:
The patent maintains continuous state synchronization by establishing a mechanism that continues to transfer state updates from the source VNF to the destination VNF even after the initial snapshot is taken. This continuous action ensures that the destination VNF receives all state changes that occur after the snapshot, preventing information loss and maintaining state accuracy throughout the migration process.
Data Source
AI summary
A method for migration of a virtual network function, VNF, from a source node to a destination node includes receiving by the destination node a snapshot of a state of the virtual network function implemented by the source node and receiving by the destination node state update elements encoding a change of the state of the virtual network function implemented by the source node caused by processing of one or more data packets received by the source node since the snapshot.