PIM Assert State Re-Convergence After Router Switchover
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multicast routing systems face inefficiencies and duplicative packet forwarding due to the loss of multicast distribution tree and PIM assert state information during router downtime or switchover events, leading to prolonged convergence loss and unnecessary PIM assert elections.
Innovation Solution
Implementing a method for routers to forward PIM join messages, participate in assert elections, and store state information, while also sending modified hello and join messages with assert state request options to expedite re-convergence of PIM assert states, ensuring only the PIM assert winner triggers further elections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If routers re-establish multicast distribution tree information after convergence loss, then multicast routing convergence is improved, but PIM assert state information is lost requiring additional elections
Solution Approach 1:
The patent applies preliminary action by triggering a PIM assert election immediately upon detecting convergence loss, before the router finishes re-establishing its multicast distribution tree information. This ensures that when the router regains convergence, the PIM assert state is already re-established, preventing information loss and avoiding the need for additional elections later in the convergence process.
2Reliability
If PIM assert elections are triggered frequently to maintain state information, then PIM assert state convergence is improved, but network traffic and processing overhead increase
Solution Approach 1:
The patent implements feedback by monitoring the convergence state of the routing information base and only triggering PIM assert elections when actual convergence loss is detected. This conditional triggering mechanism ensures PIM assert state convergence is maintained reliably while avoiding unnecessary elections during normal operation, thus preventing increased network traffic and processing overhead.
3Loss of information
If routers store and maintain PIM assert state information continuously, then state information availability is improved, but memory usage and processing load increase during normal operation
Solution Approach 1:
The patent extracts and maintains PIM assert state information separately from the main routing information base, storing it in a dedicated data structure that can be independently managed. This allows the router to maintain state information availability without adding significant processing complexity to the main routing operations, as the PIM assert state can be handled through dedicated, simplified procedures triggered only when needed.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
This disclosure describes techniques for improving convergence of Protocol Independent Multicast assert state information in multicast groups. A method includes forwarding, by a router, a PIM join message originating from a destination host and stores distribution tree information based on the join message. The method further includes participating, by the router, in a Protocol Independent Multicast ("PIM") assert election among a plurality of routers and storing, by the router, PIM assert state information based on an outcome of the PIM assert election. The method further includes acquiring, by the router, routing information base ("RIB") convergence. The method further includes triggering by the router, or causing, by the router, another router to trigger, a PIM assert among the plurality of routers. The method further includes re-converging, by the router, with PIM assert states among the plurality of routers and storing, by the router, converged PIM assert state information.