VLAN Spanning Tree Design for Even Load Dispersion
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Solution Overview
Problem
Existing VLAN topology design methods do not effectively disperse load across the network, relying solely on total link cost which leads to inefficient utilization.
Innovation Solution
The method involves calculating link costs to determine the shortest unicast paths using the Dijkstra algorithm, detecting and blocking loops to reestablish paths through concatenated links, and establishing a spanning tree with the least cost unicast paths, ensuring even load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the total sum of link costs is used as the only factor for determining VLAN topology, then the selection process is simple, but the load dispersion across the network is poor
Solution Approach 1:
The invention changes the evaluation parameters from solely total link cost to multiple parameters including total link cost, load dispersion variance, and shortest path cost. This multi-parameter approach transforms the topology selection process to achieve both simplicity and effectiveness by systematically evaluating different spanning tree topologies against these criteria.
Solution Approach 2:
The invention introduces feedback mechanisms by calculating load dispersion variance and comparing it against threshold values. The system evaluates the impact of blocking different links on overall network performance and uses this feedback to select the optimal topology that balances total link cost with load dispersion requirements.
2Productivity
If link costs are optimized for shortest unicast paths, then path efficiency is improved, but loop detection and link blocking complexity increases
Solution Approach 1:
The invention segments the loop detection and blocking process into systematic steps: first identifying all loops in the topology, then evaluating the impact of blocking each link on shortest unicast paths, and finally selecting the link whose blocking minimizes overall path cost increase. This segmentation makes the complex process manageable and systematic.
Solution Approach 2:
The invention performs preliminary actions by pre-calculating all shortest unicast paths using the Dijkstra algorithm before selecting which link to block. This preliminary path calculation provides a foundation for evaluating the impact of potential link blockings, enabling informed decisions that maintain path efficiency while eliminating loops.
Data Source
AI summary
Apparatus for designing a virtual VLAN network includes a database representing a plurality of VLAN networks in a spanning tree topology, each of the networks being formed of a plurality of VLAN member nodes interconnected by links. In response to a network configuration request from a communications network, control circuitry determines the costs of the links, and then determines the least cost unicast paths by using a shortest path algorithm. A search is made through the least cost unicast paths for detecting a loop. If at least one loop is detected, a link of highest cost of the loop is blocked. All unicast paths of the blocked link are reestablished through links that circumvent the blocked link. A spanning tree built up with all the links accommodating the least cost unicast paths is established. Configuration command is sent to the network for configuring it according to the established spanning tree.