H-VPLS Logic Port Sharing for Fast PW Failover
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Solution Overview
Problem
In Virtual Private LAN Service (VPLS) networks, the high signaling overhead and complexity in managing large numbers of Pseudo Wires (PWs) due to full mesh requirements lead to scalability issues and increased management burdens, particularly in Hierarchical VPLS (H-VPLS) where a single inactive access link can disrupt connectivity across multiple VPNs.
Innovation Solution
Implementing a method where primary and standby Pseudo Wires share a logic port number, allowing for fast switching between them by modifying the logic port table's public network information without updating the MAC address table, thereby ensuring continuous traffic forwarding without network disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If primary and standby Pseudo Wires are implemented with separate logic port numbers, then MAC address table updates ensure accurate forwarding, but switching speed decreases and traffic loss increases during failover
Solution Approach 1:
The patent merges the logic port numbers of primary and standby Pseudo Wires into a single shared identifier. This allows the MAC address table to associate MAC addresses with the shared logic port number, enabling fast failover without table updates. When the primary PW fails, traffic is immediately redirected to the standby PW using the same logic port number, achieving both forwarding accuracy and rapid switching.
Solution Approach 2:
The shared logic port number acts as an intermediary between the MAC address table and the actual Pseudo Wire identifiers. Instead of directly updating MAC address entries when switching between primary and standby PWs, the system uses the shared logic port number as a stable reference point, decoupling the forwarding table from the specific PW state and enabling rapid failover.
2Reliability
If full mesh Pseudo Wire configuration is implemented, then connectivity between all VPNs is ensured, but signaling overhead and management complexity increase significantly
Solution Approach 1:
The patent segments the full mesh PW configuration into hierarchical levels, organizing PWs in a structured manner that reduces the number of direct connections required while maintaining connectivity. This segmentation allows for more manageable configuration and lower signaling overhead while still ensuring that all VPNs remain connected through the segmented PW structure.
Data Source
AI summary
In a method for fast switching traffic in a hierarchical virtual private LAN service for use in a User-facing Provider Edge (UPE) device, a shared logic port number is assigned to each pair of primary pseudo wire and standby pseudo wire. A MAC address associated with a pair of primary pseudo wire and standby pseudo wire is associated with a logic port number shared by the primary pseudo wire and standby pseudo wire. Filling, in a logic port table, for each logic port entries containing: a logic port number, a primary pseudo wire inbound-label, a standby pseudo wire inbound-label, a primary pseudo wire outbound-label, a standby pseudo wire outbound-label and information of leaving a public network. Setting the corresponding information of leaving the public network in the logic port table depending upon whether the primary pseudeo wire is active or inactive.