Proxy Multicast State Management via Interface Tracking Tables

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Solution Overview

Problem

Current methods for managing multicast subscriber nodes in proxy devices are inefficient and lack scalability due to the processor-intensive process of recalculating the aggregate state of interfaces, which is exacerbated by frequent membership changes from subscriber nodes, especially in large networks like IPTV systems.

Innovation Solution

Implementing an interface tracking table to manage the aggregate state between a downstream proxy device and an upstream multicast router, independent of the forwarding information base and membership database, allowing for quicker updates and reduced resource usage by tracking only the subset of multicast sources required by the aggregate state of subscriber nodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the proxy device uses the traditional method to calculate aggregate state by processing all multicast sources in the membership database, then the aggregate state can be accurately determined, but the processor load increases significantly and the update time increases

Engineering Contradiction:

Improveaggregate state accuracyVSAvoidupdate speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent divides the membership database into interface-level tracking tables that maintain only the aggregate state information needed for each interface. Instead of processing all multicast sources globally, each interface has its own tracking table that segments the data to only include sources relevant to that interface, dramatically reducing the processing scope during updates.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extracts only the essential aggregate state information from the comprehensive membership database and stores it in separate interface tracking tables. This extraction removes unnecessary detailed subscriber information while retaining the critical aggregate state data needed for routing decisions, enabling fast updates without reprocessing entire membership databases.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If the proxy device reprocesses the group membership state of all circuits whenever a change occurs on a single circuit, then the aggregate state remains accurate, but the processing time and processor resources increase significantly

Engineering Contradiction:

Improveaggregate state accuracyVSAvoidupdate delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the global membership state into independent interface-level tracking tables. Each interface maintains its own aggregate state information, allowing changes to be processed locally without triggering reprocessing of other interfaces. This segmentation enables parallel processing and eliminates the need to reprocess all circuits when one circuit changes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent pre-establishes interface tracking tables with the necessary aggregate state information before changes occur. By maintaining this pre-organized structure, the system can quickly update only the affected interface table without needing to reprocess the entire membership database, reducing update time while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If the proxy device maintains detailed membership information for each subscriber node in the forwarding information base, then individual subscriber requirements can be accurately tracked, but the device complexity and memory requirements increase

Engineering Contradiction:

Improvesubscriber requirement tracking accuracyVSAvoiddata structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the aggregate state information from the detailed membership database and stores it in simplified interface tracking tables. This extraction removes individual subscriber node details while retaining the essential aggregate state data needed for routing decisions, reducing data structure complexity and memory requirements.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different levels of detail to different data structures: the membership database maintains detailed individual subscriber information locally, while the interface tracking tables maintain simplified aggregate state information. This local quality differentiation allows the system to track individual requirements when needed while using simpler structures for aggregate management.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8559427B2Efficient way to manage host subscription state on a proxy device

Publication Date: 2013.10.15 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

In a proxy for an upstream multicast router using IGMP or MLD, a process efficiently and scalably manages an interface between the upstream multicast router and the proxy by tracking a subset of multicast sources from the plurality of multicast sources required by an aggregate state of the plurality of multicast subscriber nodes. The tracking uses an interface tracking table for determining the aggregate state for the interface instead of a forwarding information base (FIB) and membership database that tracks more specific data detailing each multicast source required by each multicast subscriber node. The process receives an IGMP or MLD membership report with at least one change in the set of multicast sources to be received on the interface, updates the interface tracking table to reflect the at least one change in the subset of multicast sources and notifies the upstream multicast router of the at least one change.