Multiple SCTP Associations for S1AP Signaling Load Distribution

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Solution Overview

Problem

Current SCTP association techniques in LTE networks are limited by the inability to handle multiple hardware failures gracefully, leading to connectivity issues and scalability problems, as they establish only a single SCTP association between an eNB and MME, causing all UEs to disconnect upon failure, and result in overloaded nodes due to concentrated S1AP traffic.

Innovation Solution

Introducing the capability to establish multiple SCTP associations per S1AP connection, allowing dynamic addition and removal of associations during the S1AP connection lifetime, enabling load distribution and graceful traffic movement between associations for maintenance, expansion, and network slicing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single SCTP association is established between eNB and MME, then the S1AP connection is simple to manage, but all UEs disconnect upon SCTP failure and the node becomes overloaded

Engineering Contradiction:

ImproveS1AP connection management simplicityVSAvoidUE connectivity reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent divides the single SCTP association into multiple SCTP associations (primary and secondary), allowing independent operation of each association. This segmentation ensures that failure in one association does not affect others, thereby improving reliability while maintaining manageable complexity through structured association management.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different qualities to different SCTP associations - the primary association handles normal traffic while the secondary association provides backup. Each association can be independently configured and managed, allowing localized optimization and failure isolation without affecting the entire S1AP connection.

Inventive Principle:

Principle #3Local quality

2Device complexity

If a single SCTP association is used, then the node structure is simple, but the node becomes overloaded due to concentrated S1AP traffic

Engineering Contradiction:

Improvenode structure simplicityVSAvoidS1AP signaling load capacity

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent segments the S1AP signaling traffic across multiple SCTP associations, distributing the load from a single concentrated stream to multiple parallel streams. This segmentation increases the node's signaling load capacity without significantly increasing structural complexity, as the associations are managed through existing S1AP mechanisms.

Inventive Principle:

Principle #1Segmentation

3Reliability

If multiple SCTP associations are established, then UE connectivity reliability improves and load distribution is enabled, but the association management becomes more complex

Engineering Contradiction:

ImproveUE connectivity reliabilityVSAvoidassociation management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the S1AP connection management mechanism universal by using existing S1AP procedures and message types to manage multiple SCTP associations. The same management mechanisms used for single association are extended to handle multiple associations, reducing the need for new complex management protocols and minimizing the increase in management complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If SCTP re-establishment occurs, then network robustness is improved, but all UEs are reset which causes service disruption

Engineering Contradiction:

Improvenetwork robustnessVSAvoidUE connection restoration time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments UE connections across multiple SCTP associations, so that re-establishment of one association does not affect others. This allows the network to maintain robustness through re-establishment procedures while minimizing service disruption, as only affected UEs are impacted rather than all UEs connected to the node.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent establishes a secondary SCTP association in advance as a backup to the primary association. When re-establishment is needed, the secondary association can take over immediately, reducing the downtime and service disruption caused by SCTP re-establishment procedures.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11800577B2Multiple SCTP associations per S1AP connection and moving S1AP signaling connection between SCTP associations

Publication Date: 2023.10.24 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Certain embodiments disclose systems, methods, and apparatus for establishing and using multiple Stream Control Transmission Protocol (SCTP) associations. An example method includes a network node establishing a first SCTP association and a second SCTP association for an application protocol connection with a core network node. The network node moves a user equipment (UE) associated signaling stream from the first SCTP association to the second SCTP association.