TRILL MAC Entry Clearing via RBridge OAM Packets
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Solution Overview
Problem
In TRILL networks, when the topology accessed by a local terminal changes, existing technologies fail to clear MAC forwarding entries in a timely manner, leading to forwarding failures due to the use of outdated entries.
Innovation Solution
A method and device that detect changes in network topology and send specific packets through an RBridge channel to instruct connected routing bridges to clear corresponding MAC forwarding entries, using OAM channel headers with TCN or MAC flush packets to ensure rapid convergence of data traffic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-homing access manner is used to improve reliability of network access, then network reliability is improved, but MAC forwarding entry clearing timeliness deteriorates leading to forwarding failures
Solution Approach 1:
The patent applies preliminary action by proactively clearing MAC forwarding entries on remote RBs when topology changes are detected at the edge RB, before forwarding failures can occur. The edge RB sends TCN or MAC flush packets to remote RBs to preemptively clear their MAC forwarding entries, preventing the use of outdated entry information that would cause forwarding failures in multi-homing scenarios.
Solution Approach 2:
The patent implements feedback mechanisms where edge RBs monitor topology changes in accessed networks and provide feedback to remote RBs through OAM channel packets. When the edge RB detects a topology change, it sends feedback packets (TCN or MAC flush) to remote RBs, which then clear their MAC forwarding entries and can send confirmation feedback, ensuring synchronized state updates across the TRILL network.
2Stability of the object's composition
If conventional layer 2 network topology changes are not communicated timely to remote RBs, then network stability is maintained, but forwarding functionality deteriorates due to outdated MAC forwarding entries
Solution Approach 1:
The patent uses OAM channel packets as intermediaries to transmit topology change information from edge RBs to remote RBs. These intermediary packets (TCN or MAC flush packets sent through the RBridge channel) carry the necessary information to update MAC forwarding entries, bridging the information gap between topology changes and forwarding plane updates without disrupting network stability.
Solution Approach 2:
The patent introduces dynamic response to topology changes by enabling remote RBs to adapt their MAC forwarding entries based on real-time topology information. Instead of static forwarding tables, the system dynamically updates MAC forwarding entries when topology changes are detected, allowing the network to maintain both stability and forwarding reliability through controlled adaptability.
Data Source
AI summary
The present application provides a method and a device for clearing a MAC forwarding entry. The method includes: detecting, by a first RB, that a topology of a network accessed by a local terminal changes; and sending, by the first RB, a first packet to a second RB, so that the second RB clears a corresponding forwarding entry after receiving the first packet, where the second RB refers to an RB configured with at least one VLAN the same as that of the first RB.