VLAN-Specific Tunnel Selection for Loop-Free Overlay Forwarding
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Solution Overview
Problem
Existing technologies face challenges in facilitating loop-free traffic forwarding in overlay networks due to the use of redundant tunnels, particularly when switches from different vendors or geographic dispersion, leading to slow reaction times in loop detection and configuration.
Innovation Solution
A switch distributes VLANs among redundant tunnels, selecting an active tunnel for each VLAN and configuring the corresponding TNI only on that tunnel, while disabling it on standby tunnels, ensuring loop-free forwarding and quick failover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant tunnels are used for traffic forwarding in overlay networks, then reliability is improved, but loop-free forwarding becomes difficult to ensure
Solution Approach 1:
The patent segments the redundant tunnel group into a primary tunnel and secondary tunnels. Each tunnel is assigned a specific role (active or standby) with clear criteria for selection and failover. This segmentation resolves the contradiction by maintaining reliability through redundancy while simplifying loop prevention through role-based management.
Solution Approach 2:
The patent implements preliminary actions by pre-configuring standby tunnels and establishing failover criteria before failures occur. The system proactively identifies and designates primary and secondary tunnels, and pre-sets the conditions for automatic failover. This eliminates the need for complex real-time loop detection, as the topology is designed to be loop-free from the start.
2Difficulty of detecting and measuring
If traditional loop detection protocols are used in geographically dispersed overlay networks, then loop detection capability is provided, but reaction time is slow
Solution Approach 1:
The patent implements preliminary topology design where the network architecture itself prevents loops through hierarchical tunnel selection. By pre-establishing primary and standby tunnel relationships with clear selection criteria, the system eliminates the need for slow real-time loop detection protocols, achieving instant reaction to topology changes.
Solution Approach 2:
The patent introduces dynamic tunnel selection based on real-time topology changes and failure conditions. The system can dynamically switch between primary and standby tunnels while maintaining loop-free forwarding through predefined selection criteria. This dynamic approach provides both loop detection capability and fast reaction time.
3Reliability
If VLANs are distributed among redundant tunnels without active tunnel selection, then tunnel redundancy is maintained, but traffic loops occur
Solution Approach 1:
The patent segments VLAN traffic forwarding by assigning specific VLANs to specific tunnels based on active tunnel selection. Each tunnel becomes responsible for particular VLANs, and the system maintains redundancy by having standby tunnels ready to take over. This segmentation prevents traffic loops while preserving reliability through clear traffic-tunnel mapping.
Solution Approach 2:
The patent applies local quality by making each tunnel have different functional properties - the primary tunnel actively forwards VLAN traffic while standby tunnels remain in standby mode with specific activation criteria. This differentiation in local tunnel qualities (active vs. standby status) prevents loops while maintaining overall system redundancy.
4Adaptability or versatility
If TNI is configured on all redundant tunnels, then tunnel flexibility is improved, but traffic looping increases
Solution Approach 1:
The patent segments TNI configuration by assigning TNIs to specific tunnels based on their active or standby status. The primary tunnel receives TNI configuration for active VLAN forwarding, while standby tunnels have TNI configured only conditionally. This segmented approach provides the flexibility of TNI configuration on multiple tunnels while preventing loops through controlled activation.
Solution Approach 2:
The patent implements preliminary TNI configuration strategy where TNIs are pre-configured on primary tunnels and conditionally configured on standby tunnels based on failure detection. This preliminary approach provides tunnel flexibility when needed while preventing traffic loops by controlling which tunnels have active TNI configurations at any given time.
Data Source
AI summary
A system for facilitating loop-free traffic forwarding is provided. During operation, the system can operate a switch as a tunnel endpoint for a plurality of tunnels with corresponding remote endpoints. The system can determine a tunnel network identifier (TNI) associated with a respective virtual local area network (VLAN) configured at the switch. The system can then enable the TNI for a first tunnel among the plurality of tunnels for carrying traffic of the VLAN. Here, traffic of the VLAN is only forwarded over the first tunnel. Therefore, the system can prevent the rest of the plurality of tunnels from looping the traffic of the VLAN back to the switch. The system can select a second tunnel as a standby tunnel for the TNI from the rest of the plurality of tunnels. If the first tunnel is unavailable, the system can enable the TNI for the second tunnel for traffic forwarding.