Multicast Distribution Tree Formation for mVPN Scalability
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Solution Overview
Problem
Existing solutions for multicast virtual private networks (mVPNs) are complex and lack scalability in providing quality-of-service (QoS) assurance and traffic-engineering (TE) path support, particularly in service provider networks.
Innovation Solution
A data multicast distribution tree (MDT) is formed by monitoring multicast data traffic rates and sending join messages to receiver PE routers when thresholds are exceeded, using multicast resource reservation protocol-traffic engineering (mRSVP-TE) to establish efficient data MDTs that offload traffic from default MDTs, enabling interworking with protocol-independent multicast (PIM) on customer sites and mRSVP-TE on service provider networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If BGP is extended with seven types of Network Layer Reachability Information (NLRI) and four new BGP attributes to support mVPN, then mVPN functionality is achieved, but the solution becomes complex to implement and lacks scalability
Solution Approach 1:
The patent introduces a border router as an intermediary that establishes a multicast distribution tree (MDT) between the source PE router and receiver PE routers. This border router mediates the complex BGP-mVPN interactions by translating and simplifying the signaling process, thereby reducing implementation complexity while maintaining mVPN functionality
Solution Approach 2:
The patent segments the mVPN signaling process into distinct components: default MDT for control plane traffic, data MDT for user data traffic, and separate join message protocols. This segmentation allows each component to be optimized independently, reducing overall system complexity
2Ease of manufacture
If a default MDT is used for all multicast traffic, then setup is simple, but bandwidth is wasted by delivering traffic to all PE routers including those not interested in the traffic
Solution Approach 1:
The patent implements dynamic MDT creation where data MDTs are established on-demand based on receiver interest. When a receiver PE router sends a join message for a specific multicast group, the system dynamically creates a data MDT path from the source to the receiver, ensuring traffic is delivered only where needed and eliminating bandwidth waste
Solution Approach 2:
The patent segments multicast traffic into two types: control plane traffic using the default MDT and user data traffic using dedicated data MDTs. This segmentation allows the system to maintain simple default MDT setup while creating optimized data MDTs only for active user traffic, balancing simplicity with bandwidth efficiency
3Loss of energy
If data MDT is dynamically created based on traffic rate thresholds, then bandwidth efficiency is improved, but additional monitoring and control mechanisms are required
Solution Approach 1:
The patent implements a feedback mechanism where the border router continuously monitors traffic rates on the default MDT and compares them against configured thresholds. When thresholds are exceeded, the system automatically triggers data MDT creation, providing intelligent bandwidth optimization through automated feedback-based control without requiring complex manual configuration
Data Source
AI summary
In a source provider edge (PE) router, a method of forming a data multicast distribution tree (MDT) comprising the steps of monitoring a rate of multicast data traffic within a default MDT, determining that the rate exceeds a threshold, sending a join message to at least one receiver PE router in response to the determining, wherein the join message comprises a MDT number that identifies the data MDT, receiving a path message from the at least one receiver PE router and thereby forming the data MDT, and sending multicast data traffic via the data MDT.