Multicast Packet Forwarding with RPF Sub-Entries for Fast Failover
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Solution Overview
Problem
Conventional multicast communication systems experience long service recovery times when a communication link between a multicast source and a router fails, necessitating the network device to send a multicast joining message to another router, which prolongs the recovery process.
Innovation Solution
A packet forwarding method utilizing a reverse path forwarding (RPF) entry with sub-entries to route multicast packets through alternative network devices within a device group, ensuring seamless forwarding even when one device or link fails, by using identifiers and metrics to determine optimal paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the network device sends a multicast joining message to another router when a communication link fails, then the multicast service can be restored, but the service recovery time becomes long
Solution Approach 1:
The patent pre-establishes multiple RPF entries (first RPF entry and second RPF entry) in the network device before any link failure occurs. Each RPF entry corresponds to a different upstream router (first router and second router). When a link fails, the network device can immediately switch to using the alternative pre-configured RPF entry without needing to send new joining messages, thus achieving fast service recovery while maintaining reliability
Solution Approach 2:
The patent enables dynamic switching between different RPF entries based on link status. The network device monitors the communication links and can dynamically select which RPF entry to use for forwarding multicast packets. This dynamic adaptation allows the system to maintain reliable multicast service while minimizing recovery time by quickly transitioning to alternative paths when failures occur
Data Source
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AI summary
A packet forwarding method is disclosed. The method includes: A first network device receives a first multicast packet sent by a multicast source device and forwarded by a first device group, where the first device group includes a second network device and a third network device, and the first multicast packet is forwarded to the first network device by one network device in the first device group. The first network device determines, according to a reverse path forwarding RPF entry, that the first multicast packet is a multicast packet forwarded by the first device group, where the RPF entry includes a first sub-entry and a second sub-entry, the first sub-entry indicates the first network device to forward the first multicast packet sent by the second network device, and the second sub-entry indicates the first network device to forward the first multicast packet sent by the third network device. The first network device sends the first multicast packet to a multicast destination device according to the RPF entry. This application shortens a service recovery time when any network device in the first device group fails or a link corresponding to the network device fails.