Bandwidth-Constrained Multipath Segment Routing

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Solution Overview

Problem

Current segment routing technologies face challenges in efficiently computing and provisioning multipaths that satisfy bandwidth constraints, leading to overloaded paths and packet drops due to insufficient bandwidth in network links.

Innovation Solution

A controller computes initial shortest paths based on network topology and modifies the model by adding bandwidth overflow metrics to links with insufficient bandwidth, iteratively recalculating paths until a solution is found that does not exceed link bandwidths, thereby ensuring bandwidth-constrained multipath SR path computation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If initial shortest paths are computed without bandwidth constraints, then path computation speed is improved, but bandwidth constraints are violated leading to overloaded paths and packet drops

Engineering Contradiction:
Improvepath computation speedVSAvoidbandwidth constraint satisfaction
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-computing bandwidth metrics and incorporating them into the path computation process before actual traffic routing. The controller calculates available bandwidth for each link and integrates this information into the shortest path algorithm, ensuring bandwidth constraints are considered from the outset rather than addressing overloading after the fact.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by making the path computation adaptive to current network conditions. The bandwidth metrics are dynamically updated based on real-time network state, and the shortest path calculation adjusts accordingly. This allows the system to respond to changing bandwidth availability while maintaining computational efficiency.

Inventive Principle:
Principle #15Dynamics

2Reliability

If bandwidth constraints are enforced in path computation, then path reliability is improved, but path computation complexity increases

Engineering Contradiction:
Improvebandwidth constraint satisfactionVSAvoidpath computation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by transforming the bandwidth constraint problem into a metric adjustment problem. Instead of adding complex constraint checking logic, the system modifies the link metrics to reflect bandwidth availability, allowing standard shortest path algorithms to naturally avoid overloaded links. This reduces computational complexity while ensuring constraint satisfaction.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses an intermediary approach by introducing bandwidth metrics as an intermediate layer between network topology and path selection. These metrics act as a mediator that translates bandwidth constraints into form suitable for shortest path computation, simplifying the overall computation process while enforcing constraints.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If multiple paths are provisioned for load balancing, then network throughput is improved, but bandwidth management complexity increases

Engineering Contradiction:
Improvenetwork throughputVSAvoidbandwidth management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies merging by combining multiple paths into a unified multipath structure that is collectively optimized for bandwidth constraints. Rather than managing each path independently, the system computes and provisions multiple paths as an integrated solution, sharing bandwidth information and coordination logic across all paths in the multipath set.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements universality by creating a multipath provisioning mechanism that simultaneously achieves load balancing and bandwidth constraint satisfaction. The same computational framework that selects individual paths also ensures collective bandwidth management, making the system multi-functional without requiring separate mechanisms for each objective.

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

Data Source

PatentEP3979598B1Bandwidth constraint for multipath segment routing
Publication Date: 2024.07.03 JUNIPER NETWORKS INC
  • EP3979598B1 patent drawingFigure 1
  • EP3979598B1 patent drawingFigure 2A
  • EP3979598B1 patent drawingFigure 2B

AI summary

In an example, a method includes computing, by a computing device, for a segment routing policy that specifies a bandwidth constraint for the segment routing policy, first shortest paths through a network of network nodes, wherein each shortest path of the first shortest paths represents a different sequence of links connecting pairs of the network nodes from a source to a destination; in response to determining, by the computing device based on the bandwidth constraint for the segment routing policy, a link of one of the first shortest paths has insufficient bandwidth to meet a required bandwidth for the link, increasing a metric of the link; computing, by the computing device, for the segment routing policy that specifies the bandwidth constraint, based on the increased metric of the link, second shortest paths through the network of network nodes; and provisioning the second shortest paths in the network of nodes.