EAPS Ring Network Fast-Switchover Database Entries
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Solution Overview
Problem
In Ethernet automatic protection switching (EAPS) systems, flushing forwarding databases on nodes during network failures leads to temporary network connectivity loss and data packet loss due to the time required to relearn forwarding routes after a fault occurs.
Innovation Solution
The introduction of a fast-switchover (FSWO) field in forwarding database entries and a port array to flood traffic during failover periods, ensuring continuous connectivity by indicating susceptible entries and allowing immediate rerouting of data frames and packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If forwarding databases are flushed during network failure to ensure correct routing, then routing accuracy is improved, but network connectivity is temporarily lost and data packets are dropped
Solution Approach 1:
The system performs preliminary actions by pre-calculating and storing alternative forwarding paths in the forwarding database before the actual network failure occurs. When a link failure is detected, these pre-computed alternative paths are immediately activated without flushing the forwarding database, thus maintaining both routing accuracy and network connectivity.
Solution Approach 2:
The invention cushions against connectivity loss by maintaining multiple valid forwarding entries in the database that can serve as backups. When a failure occurs, the cushion of pre-prepared alternative paths prevents the need to flush the database, absorbing the shock of the failure event and maintaining continuous connectivity.
2Manufacturing precision
If forwarding database entries are relearned after flushing, then routing correctness is improved, but time is lost during the relearning period
Solution Approach 1:
The system performs preliminary computation of alternative paths and stores them in the forwarding database before failures occur. This eliminates the need for time-consuming relearning after failures, as the correct alternative routing information is already prepared and immediately available.
Solution Approach 2:
The invention skips the traditional flush-and-relearn process entirely by using pre-computed alternative paths. The system rushes through the failure event by immediately switching to alternative paths without the time-consuming intermediate steps of flushing and relearning, thus minimizing time loss.
3Stability of the object's composition
If the secondary port is blocked during normal operation to prevent loops, then network stability is improved, but routing flexibility is reduced
Solution Approach 1:
The system performs preliminary preparation by computing and storing alternative forwarding paths while the secondary port is blocked during normal operation. This allows the network to maintain stability with the primary path while having pre-prepared alternative routes ready for immediate activation when failures occur, thus maintaining both stability and flexibility.
Solution Approach 2:
The invention makes the routing configuration dynamic by allowing the secondary port to transition between blocked and unblocked states based on network conditions. The forwarding database dynamically switches between primary and alternative paths, enabling the system to adapt its routing flexibility while maintaining stability during normal operation.
Data Source
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AI summary
A ring network (200) with an automatic protection switching domain includes a control VLAN and at least one data VLAN. A master node (210) in the ring is connected to at least one transit node (220, 230, 240). Each node in the ring network is linked to an adjacent node by a primary port (Pl) or a secondary port (P2). The master node (210) receives notification of a fault via the control VLAN, the fault indicating a failed link between adjacent nodes. In response, the master node (210) unblocks its secondary port to traffic on the data VLAN (s). The forwarding database entries on the master node and on the transit node(s), (220, 230, 240) are flushed. Data traffic is flooded to the ring network until forwarding database entries on the master node (210) and on the transit node(s) (220, 230, 240) have been reestablished.