Layer 2 Access Device MAC Address Translation for Network Scalability

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Solution Overview

Problem

Current broadband access networks face limitations in MAC address table capacity due to the increasing number of service terminals and devices, leading to inefficient IP address allocation and network maintenance challenges when implementing Layer 3 routing.

Innovation Solution

An access device replaces the source MAC address of Layer 2 packets with a public MAC address based on packet attribute information, reducing the need for MAC address forwarding table items in convergence layer devices and eliminating the necessity for assigning IP addresses to broadband access devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If Layer 3 routing is performed in broadband access devices to reduce MAC address table capacity requirements, then the MAC address forwarding table items in convergence layer devices are reduced, but IP address space becomes scattered and address utilization ratio decreases

Engineering Contradiction:
ImproveMAC address forwarding table itemsVSAvoidIP address allocation and network maintenance
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent introduces a public MAC address as an intermediary between user terminals and the convergence layer device. Instead of using Layer 3 routing that requires IP address allocation, the access device performs Layer 2 MAC address translation by replacing source MAC addresses with a public MAC address. This intermediary approach allows the convergence layer device to handle fewer MAC address entries while maintaining Layer 2 forwarding, avoiding the IP address scattering problem entirely.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If each broadband access device is assigned an IP address segment to perform Layer 3 routing, then user terminals can be accessed, but the IP address space becomes very scattered and address utilization ratio decreases

Engineering Contradiction:
ImproveUser terminal access capabilityVSAvoidIP address space utilization efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent extracts the routing function from the broadband access device and relocates it to the convergence layer device. The access device only performs Layer 2 MAC address translation, while the convergence layer device handles Layer 3 routing decisions. This extraction eliminates the need for IP address segments at access devices, centralizing IP address management and improving overall address utilization efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The public MAC address serves as a mediator that enables user terminal access without requiring IP address allocation at the access device. By using MAC address translation as an intermediary mechanism, the system achieves user access capability while avoiding the IP address scattering problem that would result from assigning IP segments to each access device.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If Ethernet switches with limited MAC based forwarding table capacity are used, then device complexity is reduced, but the number of users that can be accommodated is limited

Engineering Contradiction:
ImproveMAC address forwarding table capacityVSAvoidNumber of supported users
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent merges multiple user MAC addresses into a single public MAC address at the access device. By translating numerous individual user MAC addresses to a unified public MAC address before forwarding to the convergence layer device, the system effectively combines multiple address entries into one, allowing Ethernet switches with limited forwarding table capacity to support a much larger number of users.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP1748603B2A transmission method for message in layer 2 and an access device
Publication Date: 2012.03.07 HUAWEI TECH CO LTD
  • EP1748603B2 patent drawingFigure 1
  • EP1748603B2 patent drawingFigure 2
  • EP1748603B2 patent drawingFigure 3~4

AI summary

A method for Layer 2 packet transmission is disclosed, wherein a corresponding relationship between packet attribute information and public MAC addresses is configured in an access device such that the access device could find a corresponding public MAC address in the corresponding relationship when receiving a packet from a user terminal, then replaces the source MAC address with the public MAC address found, and then sends the packet to a convergence layer device. A method for transmission of a Layer 2 packet without character information is also disclosed. The access device needs to obtain the packet attribute information and carry the information in the packet to be sent to the convergence layer device. An access device is also disclosed. As a result, the capacity of the VLAN and the MAC address table items needed for the convergence layer device to convert MAC addresses is greatly decreased.