Optical Network Edge Control Plane via Host Node Summary Advertising

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Solution Overview

Problem

Extending control plane functions to network edges in optical transport networks leads to a proliferation of Link State Advertisement (LSA) traffic and large topology databases, degrading topology discovery, route computation, and failure recovery functions.

Innovation Solution

Designating core nodes and tail nodes within the network, where core nodes route traffic between each other and host tail nodes, which are limited to sourcing and sinking traffic, with host nodes advertising summary information to reduce LSA propagation and maintain topology databases, allowing tail nodes to participate in control plane functions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If control plane functions are extended to all network nodes including tail nodes, then network coverage and participation are improved, but control plane messaging volume and database size increase excessively

Engineering Contradiction:

Improvenetwork participationVSAvoidLSA traffic volume

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The network nodes are segmented into two categories: core nodes that fully participate in control plane functions and tail nodes that have limited participation. This segmentation allows tail nodes to be included in the network without requiring them to exchange full topology information, thereby reducing LSA traffic volume while maintaining network participation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different nodes are assigned different levels of control plane functionality based on their role in the network. Core nodes maintain full control plane capabilities for comprehensive routing decisions, while tail nodes have simplified control plane functions limited to local traffic sourcing and sinking, reducing unnecessary messaging.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If control plane functions are extended to all network nodes including tail nodes, then network coverage and participation are improved, but topology database size increases excessively

Engineering Contradiction:

Improvenetwork participationVSAvoidtopology database size

Core Design Contradiction:

Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The topology database is segmented into core node topology information that is fully maintained and tail node topology information that is summarized. This allows tail nodes to participate in the network without requiring complete topology databases, thereby reducing database size while maintaining participation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The unnecessary topology information for tail nodes is extracted from the control plane database. Since tail nodes only source or sink traffic and do not route between themselves, their detailed topology information is removed from the global database, reducing database size while preserving essential network participation capabilities.

Inventive Principle:

Principle #2Taking out (Extraction)

3Measurement precision

If full LSA propagation is maintained for tail nodes, then topology discovery accuracy is improved, but control plane performance degrades

Engineering Contradiction:

Improvetopology discovery accuracyVSAvoidcontrol plane performance

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

Instead of implementing full LSA propagation for all nodes, partial action is applied where only core nodes exchange complete topology information. Tail nodes receive sufficient information to perform their specific functions (sourcing and sinking traffic) without the overhead of full topology discovery, thereby maintaining adequate accuracy while preserving control plane performance.

Inventive Principle:

Principle #16Partial or excessive action

4Productivity

If tail nodes are excluded from control plane functions, then control plane messaging is reduced, but network edge participation is limited

Engineering Contradiction:

Improvecontrol plane efficiencyVSAvoidnetwork edge participation

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

Tail nodes are assigned localized control plane functions appropriate to their role as traffic source and sink points. They participate in control plane activities limited to announcing their presence and receiving routing information, without engaging in full topology exchange, thus achieving edge participation with minimal messaging overhead.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9118421B2Extending control plane functions to the network edge in an optical transport network

Publication Date: 2015.08.25 CIENA CORP

AI summary

A method of extending the control plane to a network edge for a network having first set of nodes of the network are designated as core nodes, each core node being operable to route subscriber traffic between a pair of neighbor core nodes and a second set of control-plane enabled nodes of the network designated as tail nodes, each tail node connected to a core node and operating only as a source or sink of subscriber traffic. Each core node that is connected to at least one tad node is designated as a host node. The host node is controlled to advertise summary information of its connected tail nodes to other core and tail nodes in the network, thus making it possible to extend control plane function to the tail nodes which can calculate connection routes, set-up/tear-down connections and perform connection failure recovery functions.