Multicast Path Switching with Blocked-Node Control Packet Penetration

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Solution Overview

Problem

In ring network topologies, existing service restoration methods take a long time due to the blocking of multicast control packets, leading to poor user experience during path switching processes.

Innovation Solution

A method where multicast control packets are equipped with a penetration identifier to bypass blocked nodes, allowing for pre-established negotiation with the multicast server and forwarding table entries, thereby enabling immediate forwarding of service packets upon unblocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If multicast control packets are blocked during path switching, then network stability is maintained, but service restoration time increases

Engineering Contradiction:
Improvenetwork stabilityVSAvoidservice restoration time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by allowing multicast control packets to penetrate blocked nodes during path switching, enabling the establishment of service protocols and forwarding table entries in advance. This pre-negotiation mechanism ensures that when the blocked node is unblocked, service restoration occurs immediately without requiring additional negotiation time, thus resolving the contradiction between maintaining network stability through blocking and reducing service restoration time.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If multicast control packets are discarded during blocking, then broadcast storms are prevented, but service restoration requires renegotiation

Engineering Contradiction:
Improvebroadcast storm preventionVSAvoidservice restoration speed
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies local quality by differentiating the treatment of multicast control packets based on their destination and the blocking state. Specifically, multicast control packets are allowed to penetrate blocked nodes when they are destined for the multicast server, while regular multicast service packets continue to be discarded at blocked nodes. This selective penetration mechanism enables pre-negotiation without causing broadcast storms, thus resolving the contradiction between broadcast storm prevention and service restoration speed.

Inventive Principle:
Principle #3Local quality

3Reliability

If the ring network structure is maintained, then network redundancy is preserved, but packet processing capability decreases due to repeated packet reception

Engineering Contradiction:
Improvenetwork redundancyVSAvoidpacket processing capability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by enabling multicast control packets to traverse the ring network structure and establish service protocols with the multicast server before actual service packets are forwarded. This pre-negotiation through the ring structure allows the network to maintain its redundant ring topology while preparing the necessary forwarding information in advance, so that when path switching occurs, packets can be processed efficiently without repeated negotiation, thus resolving the contradiction between network redundancy and packet processing capability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3687131B1Method, apparatus and system for rapidly restoring service during path switching
Publication Date: 2026.01.21 HUAWEI TECH CO LTD
  • EP3687131B1 patent drawingFigure 1
  • EP3687131B1 patent drawingFigure 2
  • EP3687131B1 patent drawingFigure 3

AI summary

Embodiments of this application provide a fast service restoration method in a path switching process, a device, and a system. The method includes: sending, by a first device, multicast control packets to a second device and a third device through a first interface and a second interface respectively, where the multicast control packet carries a transparent transmission identifier, a port of at least one of the second device and the third device is in a blocked state controlled by a ring network protocol, the multicast control packets are sent to a multicast server through ports of the second device and the third device, negotiation of a service protocol is established with the multicast server, and a forwarding entry is established. In the embodiments of this application, the multicast control packet can penetrate a blocked node and be sent to the multicast server, so that the first device can establish the negotiation of the service protocol with the multicast server and establish a forwarding entry in advance. When the blocked node is unblocked, the first device can receive, over a normal path, a multicast service packet delivered by the multicast server. This greatly quickens restoration of a multicast service.