Mapping Server Dynamic Security Association Provisioning

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Solution Overview

Problem

Extending a software defined network to the cloud introduces scalability issues due to increased VTEPs and the need for fine-grained encryption mechanisms that enforce different policies for various virtual networks and security groups, while existing methods like the 'bolt-on' approach limit the number of connected VTEPs and lack scalability and dynamic control.

Innovation Solution

The dynamic provisioning system combines cryptographic SA negotiation with endpoint identity/location mappings, allowing for on-demand cryptographic state distribution and finer-grained encryption policies, such as per-VNI or per-security-group, to optimize the use of cryptographic resources and match the intent of high-level cryptographic policies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If per-VTEP-pair security associations are provisioned for encryption, then end-to-end security is provided, but the number of security associations increases quadratically with the number of VTEPs, limiting scalability

Engineering Contradiction:
Improveend-to-end securityVSAvoidnumber of security associations
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the cryptographic state distribution by introducing a control plane separation. The mapping server handles security association negotiation and distributes cryptographic state dynamically, while data plane VTEPs only maintain minimal state for active tunnels. This segmentation reduces per-VTEP complexity from O(N^2) to O(N) by separating control functions from forwarding functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mapping server acts as an intermediary between VTEPs for security association establishment. Instead of direct peer-to-peer SA negotiation between all VTEP pairs, the mapping server mediates the process, maintaining the global view of SAs and distributing cryptographic state on-demand. This intermediary approach reduces the complexity burden on individual VTEPs.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If fine-grained encryption policies are implemented per virtual network and security group, then security precision is improved, but the cryptographic resource requirements and system complexity increase

Engineering Contradiction:
Improveencryption policy granularityVSAvoidcryptographic resource management
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements local quality by allowing different cryptographic policies and security association parameters for different virtual networks and security groups. Each VNI and SGT can have customized encryption algorithms, key lengths, and security requirements. The mapping server enforces these local quality requirements by distributing appropriate cryptographic state to VTEPs based on the specific traffic flow's security requirements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically changes cryptographic parameters (algorithm type, key length, security association identifiers) based on the virtual network and security group requirements. The mapping server negotiates and distributes different parameter sets for different traffic flows, enabling fine-grained policy enforcement without requiring uniform cryptographic configuration across all VTEPs.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If cryptographic state is distributed to all VTEPs in advance, then security coverage is maximized, but memory usage and initialization time increase significantly

Engineering Contradiction:
Improvesecurity coverageVSAvoidcryptographic state memory
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The mapping server performs preliminary action by pre-negotiating and caching security associations in the control plane before they are needed in the data plane. When a tunnel is established, the cryptographic state is already prepared and can be quickly distributed to VTEPs on-demand, eliminating the need for VTEPs to maintain all possible SAs in advance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts the cryptographic state management function from the data plane VTEPs and places it in the control plane mapping server. The mapping server maintains the comprehensive cryptographic state repository, while VTEPs only hold the subset of state needed for active tunnels. This extraction reduces memory requirements at VTEPs while maintaining security coverage through centralized state management.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3756312B1On-demand security association management
Publication Date: 2022.10.26 CISCO TECHNOLOGY INC
  • EP3756312B1 patent drawingFigure 1
  • EP3756312B1 patent drawingFigure 2
  • EP3756312B1 patent drawingFigure 3

AI summary

A mapping server provisions network elements to optimize the cryptographic resources of a computer network. The mapping server obtains from a source network element, a request for a source endpoint to communicate with a destination endpoint across the computer network. The mapping server determines a cryptographic policy based on the source endpoint, the destination endpoint, and an availability of cryptographic resources on the network elements. The mapping server identifies a destination network element based on the cryptographic policy. The destination network element is associated with the destination endpoint. The mapping server selects a security association based on the cryptographic policy to secure a communication from the source endpoint to the destination endpoint. The security association secures the communication between the source network element and the destination network element. The mapping server provides the security association to the source network element along with a network address of the destination network element.