Segment Identifier Multicast Routing in Clos Networks

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Solution Overview

Problem

Traditional multicast traffic routing in networks faces scalability issues due to differentiated and fragmented encapsulation protocols, leading to inefficient packet replication and network bottlenecks.

Innovation Solution

Implementing protocol-independent core encapsulation techniques that use a segment identifier to define a distribution group for routers, enabling optimized multicast packet replication and load balancing, while allowing routers to operate agnostically to specific encapsulation protocols and enabling routing protocols in passive mode for core-facing interfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional multicast routing with differentiated encapsulation protocols is used, then routing functionality is provided, but scalability is limited and network bottlenecks occur

Engineering Contradiction:
ImprovescalabilityVSAvoidencapsulation protocol complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies homogeneity by standardizing encapsulation across the network core. All routers use a common segment identifier-based encapsulation format for multicast traffic, eliminating the fragmented protocol approach. This uniform structure enables scalable routing without requiring complex protocol differentiation at each router, directly resolving the contradiction between scalability and protocol complexity.

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The segment identifier acts as an intermediary element that decouples the control plane from the data plane. By introducing this intermediate abstraction layer, the patent enables routers to forward multicast traffic based on simple segment identifiers without needing to understand or process complex encapsulation protocols, thereby improving scalability while reducing device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If protocol-specific encapsulation is used at each router, then routing control is maintained, but packet replication efficiency decreases and network bottlenecks form

Engineering Contradiction:
Improvepacket replication efficiencyVSAvoidrouting control flexibility
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent segments the routing control function from the packet forwarding function. Control plane operations (route computation, membership management) are separated from data plane operations (packet replication and forwarding). This segmentation allows efficient automated packet replication based on segment identifiers while maintaining routing control through the control plane, resolving the contradiction between replication efficiency and control flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements self-service by enabling routers to automatically perform packet replication based on received segment identifiers without requiring complex protocol processing or manual intervention. The control plane distributes segment identifiers that enable routers to autonomously replicate and forward multicast packets efficiently, improving productivity while simplifying operation.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If centralized control plane is implemented, then scalability is improved, but control protocol complexity increases

Engineering Contradiction:
Improvecontrol plane scalabilityVSAvoidcontrol protocol complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the fundamental parameter used for control from complex protocol-specific identifiers to simple segment identifiers. This parameter change enables the centralized control plane to manage scalable multicast routing using straightforward identifier distribution rather than complex protocol negotiations, improving scalability while reducing control protocol complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3069471B1Optimized multicast routing in a clos-like network
Publication Date: 2018.10.10 CISCO TECHNOLOGY INC
  • EP3069471B1 patent drawingFigure 1
  • EP3069471B1 patent drawingFigure 2
  • EP3069471B1 patent drawingFigure 3

AI summary

Techniques are provided for optimizing multicast routing in a network. At a router device, a message is sent to one or more physical devices. The message is configured to solicit a response indicating a network assignment for each of the physical devices. A response message is received from each of the physical devices. The response message comprises network assignment information for each of the physical devices. For each of the physical devices, the network assignment information is translated into a segment identifier. The segment identifier is distributed to other router devices in the network.