Scalable Virtual Private Network Multicast Tree Management

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Solution Overview

Problem

Existing multicast virtual private networks face scalability issues due to inefficient data forwarding, leading to wasteful bandwidth usage and increased state knowledge maintenance, especially when using default multicast distribution trees.

Innovation Solution

A method where a new data multicast distribution tree is built only for high-bandwidth flows exceeding a predefined threshold, and low-bandwidth flows are routed over existing trees, minimizing state information and optimizing bandwidth usage by reusing existing trees based on optimal matches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If individual data MDTs are implemented for each multicast group, then bandwidth consumption is reduced, but the amount of state knowledge that must be maintained by P routers increases

Engineering Contradiction:

Improvebandwidth consumptionVSAvoidstate knowledge

Core Design Contradiction:

Loss of energyVSLoss of information

Solution Approach 1:

The patent changes the parameter of MDT creation from per-group to per-source based on bandwidth threshold. High-bandwidth flows trigger new MDT creation, while low-bandwidth flows reuse existing MDTs, dynamically adjusting system behavior based on traffic characteristics to balance bandwidth efficiency and state management

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system dynamically determines whether to create a new data MDT or reuse an existing one based on the bandwidth threshold comparison. This dynamic decision-making allows the network to adapt to varying traffic conditions and optimize the balance between bandwidth consumption and state knowledge maintenance

Inventive Principle:

Principle #15Dynamics

2Device complexity

If default MDT is used for all multicast traffic, then device complexity is reduced, but bandwidth is wasted forwarding data to dead ends

Engineering Contradiction:

ImproveMDT management complexityVSAvoidbandwidth waste

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent segments multicast traffic into high-bandwidth and low-bandwidth flows based on a predefined threshold. High-bandwidth flows receive dedicated data MDTs for efficient routing, while low-bandwidth flows share existing MDTs, creating a segmented approach that optimizes both bandwidth utilization and system complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different quality levels of service are applied to different traffic types. High-bandwidth flows get optimized dedicated MDTs with full routing precision, while low-bandwidth flows use shared MDTs with acceptable but less optimized routing, providing local optimization where most needed

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS7626995B2Method and apparatus for scalable virtual private network multicasting

Publication Date: 2009.12.01 AT&T CORP

AI summary

In one embodiment, the present invention is a method and apparatus for scalable virtual private network multicasting. In one embodiment a service network builds a new data multicast distribution tree for each high-bandwidth multicast data flow (e.g., multicast data flows that require an amount bandwidth meeting or exceeding a predefined threshold). However, if the multicast data flow is a low-bandwidth flow (e.g., if the required amount of bandwidth falls below the predefined threshold), the multicast data flow is routed over an existing multicast distribution tree in order to minimize an amount of state information that must be maintained by service provider core routers in the backbone network.