Pseudowire Circuits Over Layer 2 Bridged Networks

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Solution Overview

Problem

Conventional pseudowire techniques require a layer 3/IP network for setting up pseudowire circuits, limiting their use over pure layer 2 bridged networks and being specific to Ethernet devices and frame formats.

Innovation Solution

A method and system that enable pseudowire technology over layer 2 bridged networks by encapsulating data packets into pseudowire frames and transmitting them within MAC frames, allowing operation without a layer 3/IP network and supporting multiple client types and frame formats.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional pseudowire techniques (MPLS or L2TPV3) are used, then pseudowire circuits can be established, but a layer 3/IP network is required which limits use over pure layer 2 bridged networks

Engineering Contradiction:

Improvenetwork type compatibilityVSAvoidnetwork infrastructure requirement

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces MAC frame encapsulation as an intermediary mechanism between pseudowire technology and layer 2 bridged networks. By wrapping pseudowire frames within MAC frames, the system enables pseudowire circuits to operate over pure layer 2 networks without requiring layer 3/IP infrastructure, thus acting as a mediator that bridges the compatibility gap.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements nested encapsulation where pseudowire frames are embedded within MAC frames. This nested structure allows the pseudowire protocol to be transported over layer 2 bridged networks by nesting it inside a format (MAC frame) that is native to layer 2 networks, eliminating the requirement for layer 3/IP networks.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Adaptability or versatility

If MAC in MAC technique is used, then pseudowire circuits can be established over layer 2 networks, but it can only be used for Ethernet devices and requires Ethernet frame formats

Engineering Contradiction:

Improveclient type supportVSAvoidframe format requirement

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal pseudowire encapsulation method that works across multiple client types (Ethernet, Frame Relay, ATM, IP) and network types (layer 2 bridged networks, layer 3/IP networks, optical networks, ATM networks). The MAC frame-based approach serves as a universal container that can carry different client protocols without requiring client-specific adaptations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the encapsulation parameter from Ethernet-specific MAC in MAC to a more general MAC frame format that can accommodate multiple client types. By modifying the frame structure parameters to be less restrictive and more generic, the system achieves broader compatibility across different client devices and protocols.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS7782841B2Method and system for transporting data using pseudowire circuits over a bridged network

Publication Date: 2010.08.24 CISCO TECHNOLOGY INC

AI summary

A method for data communication across a layer 2 bridged network having two or more edge nodes configured for receiving and transmitting multiprotocol data packets. The method includes creating a pseudowire circuit across the bridged network, receiving data packets at one of the edge nodes, encapsulating data packets into pseudowire frames, encapsulating the pseudowire frames inside MAC frames, and transmitting the encapsulated frames over the carrier bridged network.