Edge Router Multicast Forwarding via Logical Interfaces

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Solution Overview

Problem

Service providers face challenges in delivering multicast content from external sources to virtual private network (VPN) customers due to logically isolated forwarding tables, which complicate routing multicast action requests and content distribution.

Innovation Solution

An edge router within the service provider network uses service-specific logical interfaces to handle multicast traffic flow, associating multicast packets with logical service interfaces and forwarding them according to public network forwarding data, bypassing VPN-specific tables to connect VPN customers seamlessly with external multicast content providers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If service providers use logically isolated forwarding tables for VPN services, then security and data isolation between different VPNs are improved, but the ability to route multicast traffic from VPN customers to external content providers deteriorates

Engineering Contradiction:

Improvedata isolation between VPNsVSAvoidaccess to external multicast content

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The forwarding table is segmented into VPN-specific tables for internal VPN traffic and a global table for external multicast content. This allows VPN customers to access external multicast content while maintaining data isolation between different VPNs, as each VPN has its own forwarding table for internal traffic but can all access the global table for external content.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The service provider's edge router acts as an intermediary between VPN customers and external content providers. It receives multicast action requests from VPN customers, translates them into appropriate routing decisions using both VPN-specific and global forwarding tables, and forwards the traffic to external content providers while maintaining VPN isolation where needed.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If service providers maintain separate forwarding tables for each VPN, then VPN security and isolation are improved, but device complexity and configuration difficulty increase when routing external multicast traffic

Engineering Contradiction:

ImproveVPN isolationVSAvoidforwarding table management

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The global forwarding table serves multiple VPNs simultaneously for accessing external multicast content. This universal table structure reduces the need for separate configurations for each VPN when accessing external content, thereby reducing overall device complexity while maintaining VPN isolation for internal traffic.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If service providers use traditional multicast routing methods, then internal multicast content distribution is simple, but external multicast content access from VPN customers becomes complex and requires dedicated physical connections

Engineering Contradiction:

Improveinternal multicast distributionVSAvoidexternal content access configuration

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The service provider's edge router uses a unified approach where the same multicast routing infrastructure handles both internal and external multicast traffic. The global forwarding table enables VPN customers to access external multicast content using the same simplified multicast routing mechanisms already in place for internal content, eliminating the need for dedicated physical connections or complex external configurations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The edge router acts as an intermediary that transparently handles external multicast content requests from VPN customers. It automatically translates internal VPN customer requests into external routing decisions using the global forwarding table, providing ease of operation for external content access without requiring complex configuration changes at the customer site.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7539205B1Service-specific logical interfaces for providing VPN customers access to external multicast content

Publication Date: 2009.05.26 JUNIPER NETWORKS INC

AI summary

A network device seamlessly handles multicast traffic flow between virtual private networks (VPNs) and content providers located external to the VPNs. For example, the network device, such as a router, comprises an interface card and a forwarding component. The forwarding component maintains forwarding data for a public network and forwarding data for the virtual private network. The interface card receives a multicast packet from a virtual private network destined for a multicast content provider external to the virtual private network. When forwarding the multicast packet, the forwarding component bypasses the forwarding data for the public network and forwards the multicast packet to the multicast content provider in accordance with the forwarding data for the public network.