VPLS Scalability via Extended VLAN Tag Mapping
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Solution Overview
Problem
Current VPLS models face scalability issues due to the limited 12-bit VLAN ID space, leading to an inadequate number of supported VLANs and VPNs, and struggle with Operations and Management (OAM) maintainability and scalability, particularly with large numbers of pseudowire meshes.
Innovation Solution
The implementation of an extended VLAN (E-VLAN) mechanism that reduces the number of pseudowires by using a 20-bit VLAN ID and Service ID field, allowing up to one million service instances, and employs Extended GVRP for efficient broadcast domain management, along with redundancy mechanisms like BPDU loopback for link and node level redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a 12-bit VLAN ID is used according to IEEE 802.1Q standard, then VLAN compatibility and standardization are improved, but the number of supported VLANs and VPNs is limited to 4,094
Solution Approach 1:
The patent transitions from a 12-bit VLAN ID (providing 4,094 VLANs) to a 24-bit Service ID (providing 16 million VLANs), effectively adding a dimensional expansion to the identification space. This allows the system to support a vastly larger number of VLANs and VPNs while maintaining compatibility with existing IEEE 802.1Q standards through the use of an extended VLAN tag format.
2Ease of operation
If traditional VPLS models are used, then Layer 2 service emulation is achieved, but the number of pseudowires becomes unmanageably large
Solution Approach 1:
The patent merges the VLAN identification function with the Service ID field in the extended VLAN tag, allowing a single identifier to represent both the VLAN and the service instance. This consolidation eliminates the need for separate pseudowire management for each service instance, reducing the overall number of pseudowires required in the VPLS network while maintaining full Layer 2 emulation capabilities.
3Quantity of substance
If the number of pseudowires is increased to support more VLANs, then VLAN coverage is improved, but OAM maintainability and scalability deteriorate
Solution Approach 1:
The patent changes the identifier parameter from a 12-bit VLAN ID to a 24-bit Service ID, enabling a much larger addressing space. This parameter change allows the system to support millions of VLANs without increasing the number of pseudowires, thereby maintaining OAM maintainability and scalability while achieving comprehensive VLAN coverage.
Data Source
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AI summary
A VPLS model is implemented in a network-facing provider edge (n-PE) device configured to receive a packet from an access network the packet having a first Virtual Local Area Network (VLAN) tag of a first predetermined bit length The n-PE device mapping the service instance identifier of the first VLAN tag into a second VLAN tag of a second predetermined bit length greater than the first predetermined bit length, the second VLAN tag identifying a Virtual Private LAN Service (VPLS) instance The n-PE device then sends the packet with the second VLAN tag across a service provider (SP) core network via a pseudowire (PW) that functions as a logical link to another PE device