DHCPv6 Relay Agent Interface Identifier Forwarding

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Solution Overview

Problem

The existing DHCPv6 layer-3 relay agents face inefficiencies in forwarding messages due to the need for configuring global unicast or site-local addresses, which wastes resources and increases workload, and the solution of one-to-one mapping of user ports to layer-3 interfaces is not feasible in many-to-many scenarios.

Innovation Solution

The proposed method involves adding an identifier of the layer-3 interface to the Relay-forward message, allowing the DHCPv6 layer-3 relay agent to correctly forward messages without requiring global unicast or site-local addresses and reducing the number of layer-3 interfaces, by using the identifier to locate the correct interface for message forwarding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If global unicast or site-local addresses are configured for layer-3 interfaces to enable message forwarding, then message forwarding capability is improved, but IPv6 address resources are wasted and configuration workload increases

Engineering Contradiction:
Improvemessage forwarding capabilityVSAvoidIPv6 address resources
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent extracts the layer-3 interface identifier from the IPv6 address configuration requirement. Instead of using global unicast or site-local addresses to identify layer-3 interfaces, the invention uses a separate interface identifier field that is populated from the Interface-ID Option in the DHCPv6 message, thereby separating the identification function from the address configuration and eliminating the waste of IPv6 address resources.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent makes the Interface-ID Option field serve multiple functions: it not only identifies the user port as originally designed but also provides the layer-3 interface identifier for message forwarding. This multi-functionality eliminates the need for separate address configurations and reduces configuration workload while maintaining message forwarding capability.

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

2Measurement precision

If user ports are mapped one-to-one to layer-3 interfaces to enable unique identification, then message forwarding accuracy is improved, but device complexity increases and the solution becomes infeasible in many-to-many scenarios

Engineering Contradiction:
Improvemessage forwarding accuracyVSAvoidlayer-3 interface configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the identification process into two independent parts: user port identification (via Interface-ID Option) and layer-3 interface identification (via the extracted interface identifier). This segmentation allows the system to handle many-to-many mappings without requiring a one-to-one correspondence, thereby reducing device complexity while maintaining forwarding accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism - the interface identifier extracted from the Interface-ID Option - that mediates between the user port and the layer-3 interface. This intermediary allows flexible many-to-many mappings while ensuring accurate message forwarding, avoiding the complexity of strict one-to-one mapping requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If multiple layer-3 interfaces are configured to support multiple service streams, then service capability is improved, but the number of layer-3 interfaces increases and forwarding performance decreases

Engineering Contradiction:
Improveservice stream supportVSAvoidlayer-3 forwarding performance
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent merges the identification of multiple service streams into a single layer-3 interface context. Instead of creating separate layer-3 interfaces for each service stream, the invention uses the interface identifier to identify the appropriate layer-3 interface, then handles multiple service streams within that context, thereby maintaining service capability while reducing the number of layer-3 interfaces and improving forwarding performance.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3133797B1Message forwarding method, system, and relay agent device
Publication Date: 2020.10.28 HUAWEI TECH CO LTD
  • EP3133797B1 patent drawingFigure 1~2
  • EP3133797B1 patent drawingFigure 3
  • EP3133797B1 patent drawingFigure 4A~4B

AI summary

The present invention provides a message forwarding method and system, and a relay agent device. The forwarding method includes: receiving a first DHCPv6 message from a DHCPv6 client through a layer-3 interface; generating a Relay-forward message, where the first DHCPv6 message is encapsulated into the Relay-forward message and an identifier of the layer-3 interface is added therein; and sending the Relay-forward message to a DHCPv6 server. With the technical solution of the present invention, the relay agent device can correctly forward messages, resources of global unicast addresses or site-local addresses can be saved, and layer-3 forwarding performance of the relay agent device can be improved.