Segment Routing Forwarding Adjacency Setup via PCE

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Solution Overview

Problem

Current packet forwarding mechanisms, such as MPLS and IP routing, face performance limitations due to complex decision processes in network nodes, which can hinder overall network efficiency.

Innovation Solution

The implementation of Segment Routing (SR), which uses segment IDs instead of LDP labels for packet forwarding, allowing for faster and simpler forwarding engines that are not dependent on specific OSI model data link layer technologies, and enables the creation of tunnels and explicit paths through path computation elements (PCEs).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If MPLS or traditional IP routing is used for packet forwarding, then packet forwarding decisions can be made using existing protocols, but the decision process becomes complex and limits network performance

Engineering Contradiction:
Improvenetwork performanceVSAvoidforwarding decision complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the network path into discrete segments identified by segment IDs. Each segment represents a specific hop or path section, and packets are forwarded by processing segment IDs rather than performing complex routing decisions. This segmentation simplifies the forwarding process while maintaining network performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the routing decision logic from individual network nodes and centralizes it in a Path Computation Element (PCE). The PCE calculates optimal paths and distributes segment ID information to nodes, removing the complex decision-making burden from forwarding nodes and enabling simpler, faster packet forwarding.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If LDP labels are used for packet forwarding decisions, then MPLS forwarding can be implemented, but the system becomes dependent on specific OSI model data link layer technologies

Engineering Contradiction:
Improvetechnology independenceVSAvoidforwarding engine complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements universality by designing a forwarding mechanism that operates independently of specific data link layer technologies. Segment IDs provide a universal identification method that works across different OSI model layers and technologies, making the forwarding engine adaptable and versatile without being tied to LDP or specific link layer protocols.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2974176B1Segment routing: PCE driven dynamic setup of forwarding adjacencies and explicit path
Publication Date: 2020.07.01 CISCO TECHNOLOGY INC
  • EP2974176B1 patent drawingFigure 1
  • EP2974176B1 patent drawingFigure 2
  • EP2974176B1 patent drawingFigure 3

AI summary

An apparatus and method for path creation element driven dynamic setup of forwarding adjacencies and explicit path. In one embodiment of the method, a node receives an instruction to create a tunnel between the node and another node. The node creates or initiates the creation of the tunnel in response to receiving the instruction, wherein the tunnel comprises a plurality of nodes in data communication between the node and the other node. The node maps a first identifier (ID) to information relating to the tunnel. The node advertises the first ID to other nodes in a network of nodes.