Multicast Tree State Replication for Network Reliability
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Solution Overview
Problem
Existing network devices lack efficient mechanisms to preserve multicast tree state tables across multiple control planes, leading to disruptions in multicast data forwarding when one control plane becomes unavailable.
Innovation Solution
Implementing a network device with a primary and secondary multicast tree state table, where the primary table stores next-hop information for multicast streams and the secondary table is updated based on changes in the primary table, allowing for seamless switching and continuous data forwarding even if one control plane fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single control plane maintains multicast tree state table, then device complexity is low, but reliability deteriorates when control plane becomes unavailable
Solution Approach 1:
The patent creates a secondary control plane that replicates the multicast tree state table from the primary control plane. This copy ensures that if the primary control plane fails, the secondary control plane can take over and maintain multicast data forwarding without interruption, thus improving reliability while adding controlled complexity through the replication mechanism.
Solution Approach 2:
The secondary control plane proactively replicates and maintains the multicast tree state table in advance, before any failure occurs. This preliminary action ensures that when the primary control plane becomes unavailable, the secondary control plane is already prepared with the necessary state information to immediately take over, eliminating downtime and maintaining service continuity.
2Reliability
If multicast tree state table is replicated between control planes, then reliability improves, but information synchronization complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the primary control plane sends updates to the secondary control plane whenever the multicast tree state table changes. The secondary control plane acknowledges receipt and application of these updates, ensuring synchronized state information. This feedback loop prevents information loss and maintains consistency between the two control planes.
Solution Approach 2:
The patent uses an intermediary communication mechanism between the primary and secondary control planes to transfer multicast tree state information. This intermediary channel ensures reliable transmission of state updates, handling synchronization systematically and preventing information loss during the replication process.
3Loss of time
If secondary control plane is maintained, then downtime during failures is reduced, but resource utilization increases
Solution Approach 1:
The patent applies partial action by having the secondary control plane replicate only the essential multicast tree state table information needed for failover, rather than maintaining a complete duplicate of all control plane functions. This selective replication reduces resource consumption while still achieving the goal of rapid failover and minimizing downtime.
Data Source
AI summary
A network device may include a first memory to store a primary multicast tree state table for storing next-hop information for a multicast tree corresponding to a multicast stream; a second memory to store a secondary multicast tree, different than the primary multicast tree, state table for storing the next-hop information for the multicast tree corresponding to the multicast stream; a receiver to receive a data unit from a neighbor network device, the data unit including information regarding a next-hop in the multicast tree; and one or more processors. The one or more processors may update the primary multicast tree state table based on the information regarding the next-hop in the multicast tree, and update the secondary multicast tree state table, in response to the one or more processors updates the primary multicast tree state table, based on the information regarding the next-hop in the multicast tree.