VLAN Bridge Forwarding via Virtual Switching Instances
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Ethernet bridge forwarding methods are limited to forwarding frames within a single Virtual Local Area Network (VLAN) and do not support cross-VLAN forwarding, requiring Layer 3 IP routing for inter-VLAN communication and restricting broadcast to a single VLAN.
Innovation Solution
A bridge forwarding method and apparatus that determines an output VLAN ID different from the input VLAN ID based on the input port, input VLAN ID, and destination MAC address, allowing frames to be forwarded across VLANs by establishing a relationship between input ports, VLANs, and Virtual Switching Instances (VSIs), enabling multiple-to-one VLAN relationships and broadcast to multiple VLANs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Layer 2 Ethernet bridge forwarding is used, then forwarding within a single VLAN is achieved, but cross-VLAN forwarding is not supported
Solution Approach 1:
The bridge forwarding apparatus is designed to perform both traditional Layer 2 forwarding within a VLAN and new cross-VLAN forwarding functions through the VSI mechanism. By making the bridge capable of handling multiple VLAN contexts and performing VLAN ID translation, a single device can serve multiple forwarding purposes without requiring separate Layer 3 routing infrastructure, thus improving adaptability while controlling complexity.
Solution Approach 2:
The Virtual Switching Instance (VSI) acts as an intermediary mechanism that enables cross-VLAN forwarding. The VSI serves as a logical abstraction layer between the input VLAN and output VLAN, allowing the bridge to forward frames across VLAN boundaries without requiring full Layer 3 IP routing. This intermediary approach resolves the contradiction by providing cross-VLAN capability through a simplified bridging mechanism rather than complex routing.
2Adaptability or versatility
If Layer 3 IP routing is used for cross-VLAN forwarding, then inter-VLAN communication is achieved, but broadcast to multiple VLANs is not supported
Solution Approach 1:
The bridge forwarding apparatus performs multiple functions including unicast forwarding, multicast forwarding, and broadcast forwarding across multiple VLANs through the VSI mechanism. By consolidating these functions into a single bridge device rather than requiring separate Layer 3 routing for each function, the system achieves multi-VLAN broadcast capability while maintaining Layer 2 forwarding speed, thus avoiding the time loss associated with Layer 3 processing.
Solution Approach 2:
The invention adds a new dimension to VLAN handling by introducing the VSI concept that operates alongside traditional VLAN IDs. This creates a multi-dimensional forwarding capability where frames can be forwarded across VLAN boundaries through the VSI layer without requiring Layer 3 processing, enabling efficient multi-VLAN broadcast while maintaining Layer 2 performance characteristics.
3Adaptability or versatility
If one VSI corresponds to one VLAN, then simple mapping is achieved, but multiple-to-one VLAN relationships are not supported
Solution Approach 1:
The VSI is designed to support multiple-to-one VLAN relationships, allowing a single VSI to correspond to multiple VLAN IDs. This multi-functional capability enables the bridge to handle complex VLAN mappings where multiple input VLANs can be forwarded to a single output VLAN or multiple output VLANs, all through the same VSI mechanism, thus improving adaptability while managing complexity through a unified approach.
Solution Approach 2:
The invention introduces a second dimension to VLAN mapping by adding the VSI layer between the traditional one-to-one VLAN mapping. This creates a multi-dimensional mapping structure where VLAN IDs can map to VSIs, and VSIs can map to multiple VLAN IDs, enabling flexible multiple-to-one and one-to-many relationships without significantly increasing operational complexity.
4Adaptability or versatility
If Layer 2 Ethernet bridge is used, then forwarding speed is maintained, but cross-VLAN forwarding requires Layer 3 routing
Solution Approach 1:
The VSI acts as an intermediary mechanism that enables cross-VLAN forwarding while maintaining Layer 2 bridge forwarding characteristics. By introducing this logical layer between the input and output VLANs, the system can perform cross-VLAN forwarding through bridge mechanisms rather than requiring Layer 3 routing, thus achieving the desired adaptability while preserving the simplicity and speed of Layer 2 forwarding.
Solution Approach 2:
The bridge forwarding apparatus is designed to handle both traditional Layer 2 forwarding and cross-VLAN forwarding through the VSI mechanism in a unified manner. This multi-functional design allows the same bridge infrastructure to perform both types of forwarding without requiring separate processing paths, thereby achieving cross-VLAN capability while controlling the increase in device complexity.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A bridge forwarding method comprises: receiving a frame from an input port, obtaining the input VLAN ID and a destination MAC address of the frame; determining an output port and an output VLAN ID of the frame, and forwarding the frame according to the output port and the output VLAN ID. A bridge forwarding apparatus includes at least one output port used for receiving a frame from more than one VALN, at least one output port used for transmitting the frame to more than one VALN and a forwarding unit, the forwarding unit obtains the input VLAN ID and the destination MAC address in the frame, determines the output port and the output VLAN ID of the frame, and outputs the frame to the corresponding output port. The method and the apparatus of this invention can realize the bridge forwarding of the Ethernet frames between multiple VLANs.