Multi-Site Stretched Gateway State Retrieval for VM Migration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems fail to maintain existing network connections for virtual machines (VMs) when migrated between sites with stretched gateways, as the destination site lacks the necessary stateful services for these connections, leading to packet drops.
Innovation Solution
Implement a method where the destination edge server sends a threshold number of packets to the source site to retrieve state information, creates flow mappings, and uses L2-over-L3 protocols to encapsulate and forward packets, ensuring that existing connections are maintained by applying stateful services at the appropriate site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If L2 stretching is used to enable VM migration between sites, then VM mobility and IP address retention are improved, but existing network connections are broken due to state loss at the destination gateway
Solution Approach 1:
The system performs preliminary actions by having the source ESG store state information for existing connections before VM migration occurs. When the VM migrates to the destination site, the destination ESG can retrieve this pre-stored state information, ensuring that existing connections continue without interruption despite the VM moving to a different site.
Solution Approach 2:
The invention introduces an intermediary mechanism where the source ESG acts as a state repository for connections that need to be maintained after VM migration. The destination ESG queries the source ESG for state information, creating an intermediary state transfer path that allows connections to persist across site boundaries while maintaining the benefits of L2 stretching for VM mobility.
2Reliability
If stateful services are maintained at the source site after VM migration, then existing connections are preserved, but network complexity and state synchronization overhead increase
Solution Approach 1:
The system implements self-service by enabling the destination ESG to autonomously query and retrieve state information from the source ESG when needed. This eliminates the need for complex centralized state management or continuous state synchronization protocols, as each ESG independently manages its own state retrieval needs based on incoming traffic requirements.
Solution Approach 2:
The invention employs feedback mechanisms where the destination ESG monitors incoming traffic for existing connections and automatically triggers state retrieval from the source ESG when such connections are detected. This feedback-driven approach ensures that state information is retrieved only when necessary, minimizing unnecessary complexity while maintaining connection continuity.
3Reliability
If the destination ESG drops packets for connections without state, then connection security is maintained, but legitimate migrated connections are interrupted
Solution Approach 1:
The system performs preliminary state retrieval actions when the destination ESG detects traffic belonging to an existing connection. By proactively querying the source ESG for state information before processing the packet, the destination ESG ensures that legitimate migrated connections are recognized and handled correctly, preventing unnecessary packet drops while maintaining security through proper state verification.
Solution Approach 2:
The invention uses feedback loops where the destination ESG continuously monitors incoming packets for signs of existing connections and automatically retrieves state information when such connections are identified. This feedback mechanism ensures that security is maintained through proper state validation while preventing interruption of legitimate migrated connections that require state information for proper handling.
Data Source
AI summary
An example method of handling traffic for an existing connection of a virtual machine (VM) migrated from a source site to a destination site includes: receiving, at an edge server of the destination site, the traffic, the traffic being associated with a network flow; determining, by the edge server of the destination site, that a stateful service of the edge server does not have state for the network flow; sending, by the edge server of the destination site, a threshold number of packets of the traffic to a plurality of sites; receiving, at the edge server of the destination site, an acknowledgement from the source site that the source site has the state for the network flow; and creating, by the edge server of the destination site, a flow mapping to send the traffic associated with the network flow to the source site.