VLAN Tagging in WLANs Using AID Mapping
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Solution Overview
Problem
Current WLANs face computational inefficiencies in determining VLAN tags due to large MAC address fields and tables, which becomes problematic as the number of supported wireless clients increases, especially when supporting voice communications and mobility.
Innovation Solution
The solution involves creating a mapping between a client identifier, such as an Association ID (AID), and an authenticated communications path identifier, like a VLAN tag or Layer-3 tunnel tag, at the access point to efficiently manage VLAN tagging, reducing computational costs by using a smaller and easier-to-search identifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If VLAN tags are determined using MAC address fields and tables at switches or servers, then VLAN differentiation and QoS control are achieved, but computational cost increases significantly due to large MAC address fields and tables
Solution Approach 1:
The patent segments the VLAN tagging function from the switch/server to the access point, and further segments the identifier from MAC address to AID. This segmentation allows the computationally intensive VLAN determination to occur at the edge (access point) using small local tables, rather than at the core network devices with large tables, thus improving both reliability of VLAN differentiation and productivity in terms of computational efficiency
Solution Approach 2:
The patent introduces AID as an intermediary identifier between the client device and the VLAN tagging system. The AID acts as a mediator that maps clients to VLANs through small local tables at access points, avoiding the need for switches/servers to process large MAC address tables, thereby resolving the contradiction between reliable VLAN differentiation and computational efficiency
2Adaptability or versatility
If the number of supported wireless clients increases, then network capacity and versatility improve, but the size of MAC address tables and computational burden increase
Solution Approach 1:
By segmenting the identifier space from 48-bit MAC addresses to 12-bit AIDs at the access point level, the patent enables the system to support many more clients without proportionally increasing table sizes or computational complexity. Each access point maintains a small local mapping table for its associated clients, allowing the overall system to scale to support large numbers of clients while keeping individual device complexity manageable
Solution Approach 2:
The patent changes the dimension of identification from using long MAC address fields to using short AID fields combined with access point identification. This dimensional change allows the system to support more clients by distributing the identification burden across multiple access points, each with small local tables, rather than requiring a single large centralized table
Data Source
AI summary
A wireless access point is operable to tag packets received from mobile clients. For example, a VLAN tag or Layer-3 tunnel tag for a packet is determined based at least in-part on a mapping between a mobile client and tag maintained by the access point. In one embodiment the access point uses Association IDs (“AIDs”) to uniquely identify mobile clients in the BSS. Hence, the mapping is between A/Ds and VLAN tags/Layer-3 tunnel tags. The mapping may be generated by snooping authentication related communications or from information maintained by a switch, such as a MAC address to tag mapping.