SDN Policy Node Label Allocation for Traffic Flow Steering

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Solution Overview

Problem

Existing Software Defined Network (SDN) solutions face scalability issues in handling multiple traffic paths and users, particularly in downlink directions, and struggle with maintaining rules for service chaining, especially for Layer 2-based services which often disrupt network topology awareness and require frequent classification and re-tagging.

Innovation Solution

A method involving a policy node that allocates labels for traffic flows and their destinations, allowing the Software Defined Network Controller (SDNC) to create paths based on these labels, and a classifying node to associate traffic flows with labels, enabling efficient steering through the SDN without the need for extensive rule creation at each hop.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If individual user sessions are selected with five-tuple filtering for every hop in the service chain, then traffic flows can be steered through service paths, but the complexity to configure and set up increases and scaling becomes poor for the number of different traffic paths

Engineering Contradiction:
Improvetraffic flow steering capabilityVSAvoidconfiguration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the complex five-tuple filtering logic from each individual hop and replaces it with a centralized service chain identifier (SCID) mechanism. The SCID is inserted at the ingress of the service chain and carried through all hops, eliminating the need for complex per-hop filtering rules while maintaining traffic steering capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a service chain identifier (SCID) as an intermediary element that mediates between the traffic flow and the service chain processing. This SCID acts as a simplified key that routing entities can use to determine service chain processing without requiring complex filtering rules, thus reducing configuration complexity while maintaining adaptability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If all selected traffic passes a service independent of whether it is needed to simplify traffic steering rules, then traffic steering becomes simpler, but unnecessary services are processed increasing loss of time and energy

Engineering Contradiction:
Improvetraffic steering simplicityVSAvoidservice processing time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent performs preliminary classification of traffic flows at the ingress of the service chain using the SCID. This preliminary action determines exactly which traffic flows need to pass through which services, preventing unnecessary services from processing unrelated traffic and thus reducing time loss while maintaining operational simplicity.

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If the number of users that may be steered into different traffic paths increases, then network capacity is improved, but the number of rules that need to be maintained increases causing scaling problems

Engineering Contradiction:
Improvenumber of usersVSAvoidnumber of rules
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent makes the SCID a universal identifier that can represent multiple traffic flows and service chain combinations. Instead of maintaining separate rules for each user and traffic path combination, the SCID serves as a multi-functional key that can map to different service chains based on the traffic flow characteristics, allowing the system to scale to many users without proportionally increasing the number of rules.

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

4Adaptability or versatility

If Layer 2-based service chaining is implemented, then service flexibility is improved, but services become unaware of network topology and tagging/chain data is destroyed requiring new classification

Engineering Contradiction:
Improveservice chaining flexibilityVSAvoidtagging/chain data
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent embeds the SCID within the packet header at Layer 3, nesting it in a position that survives Layer 2 processing. This nested placement ensures that the tagging/chain data is preserved through Layer 2 services without being destroyed, maintaining service flexibility while preventing information loss.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP3127286B1Handling of traffic flows in a communications system
Publication Date: 2020.08.19 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3127286B1 patent drawingFigure 1
  • EP3127286B1 patent drawingFigure 2a
  • EP3127286B1 patent drawingFigure 2b

AI summary

The embodiments herein relate to a method in a policy node (103) configured to handle traffic flows in a communications system (100). The policy node (103) allocates a label-setting identifying a label, a particular traffic flow that will pass through a SDN (105), and one or more destinations (115, 120) for the particular traffic flow. The policy node (103) transmits information indicating the label-setting to a SDNC (108) configured to create a path for the traffic flow through the SDN (105) based on the label and said one or more destinations (115, 120) identified by the label-setting. The policy node (103) allocates a filter-setting defining that the particular traffic flow should be associated with the label. The policy node (103) transmits information indicating the filter-setting to a classifying node (101) configured to receive the particular traffic flow and to associate the particular traffic flow with the label.