How to Start Spanning Tree Protocol Projects Using MATLAB

To start Spanning Tree Protocol (STP) using MATLAB which is a network protocol that makes sure a loop-free topology to make a spanning tree that inactivates redundant links within Ethernet networks. This protocol is helpful for avoiding broadcast storms and making sure that effective interaction in a switched network. Here’s a basic guide to get started:

Steps to Start Spanning Tree Protocol (STP) Project in MATLAB

1. Understand STP

• Purpose:
  • In Layer 2 (Data Link Layer) networks, it helps to prevent the loops.
  • Choose the shortest path among the switches according to the cost metric.
• Key Components:
  • Bridge ID: Unique identifier for every switch.
  • Root Bridge: The central bridge within the spanning tree.
  • Path Cost: Metric utilised for computing the shortest path to the root bridge.
  • Root Port: The port on each non-root switch including lowest path cost to the root.
  • Designated Port: The port on each part, which transmits the traffic to root bridge.
  • Blocked Port: Ports not utilised to avoid loops within the spanning tree.

2. Set Project Objectives

• Replicate the STP process for determining a spanning tree.
• Envision the spanning tree including dynamic and obstructed links.
• Measure performance parameters such as path cost and link utilization.

3. Define Network Topology

Make use of an adjacency matrix or graph to denote the network.

Example: Adjacency Matrix

% Define adjacency matrix (weights represent link costs)

adjMatrix = [

0 1 3 0;

1 0 1 4;

3 1 0 2;

0 4 2 0

];

% Visualize the network

G = graph(adjMatrix, ‘upper’);

plot(G, ‘EdgeLabel’, G.Edges.Weight);

title(‘Network Topology for Spanning Tree Protocol’);

4. Implement STP Algorithm

Steps:

1. Elect the Root Bridge:
   • The switch including the smallest Bridge ID turns out to be the root.
2. Compute Path Costs:
   • Every single switch computes the shortest path to the root bridge.
3. Select Root and Designated Ports:
   • Root ports associate the switches to the root bridge.
   • Chosen ports transmit traffic on each segment.
4. Block Redundant Ports:
   • Balance ports are obstructed for avoiding loops.

MATLAB Implementation:

function spanningTree = computeSpanningTree(adjMatrix, bridgeIDs)

numNodes = size(adjMatrix, 1);

% Step 1: Elect the Root Bridge

[~, rootBridge] = min(bridgeIDs);

% Initialize variables

pathCost = inf(1, numNodes);

pathCost(rootBridge) = 0;

rootPorts = -ones(1, numNodes);

visited = false(1, numNodes);

% Step 2: Compute Path Costs

for i = 1:numNodes

[~, u] = min(pathCost + visited * inf);

visited(u) = true;

neighbors = find(adjMatrix(u, 🙂 > 0);

for v = neighbors

cost = pathCost(u) + adjMatrix(u, v);

if cost < pathCost(v)

pathCost(v) = cost;

rootPorts(v) = u;

end

end

end

% Step 3: Build the Spanning Tree

spanningTree = zeros(numNodes);

for v = 1:numNodes

if rootPorts(v) > 0

spanningTree(v, rootPorts(v)) = adjMatrix(v, rootPorts(v));

spanningTree(rootPorts(v), v) = adjMatrix(rootPorts(v), v);

end

end

end

5. Simulate STP

Determine the spanning tree to utilise the function for a given network.

Example Simulation:

% Define bridge IDs

bridgeIDs = [2, 1, 3, 4]; % Unique IDs for each switch

% Compute the spanning tree

spanningTree = computeSpanningTree(adjMatrix, bridgeIDs);

% Display the spanning tree

fprintf(‘Spanning Tree Adjacency Matrix:\n’);

disp(spanningTree);

6. Visualize the Spanning Tree

Envision the dynamic links on the network graph within the spanning tree.

Example:

% Create a graph for the spanning tree

G_spanning = graph(spanningTree, ‘upper’);

% Visualize the spanning tree

plot(G, ‘EdgeLabel’, G.Edges.Weight);

highlight(plot(G_spanning), ‘EdgeColor’, ‘r’, ‘LineWidth’, 2);

title(‘Spanning Tree Visualization’);

7. Evaluate Performance

• Path Cost: Confirm that the spanning tree reduces the entire path cost.
• Loop Prevention: Make sure that redundant links are obstructed.
• Scalability: Experiment the protocol on larger networks for scalability.

8. Extend the Project

• Dynamic Topology: We need to replicate the link failures or additions and recalculate the spanning tree.
• Load Balancing: Enhance the spanning tree, equalizing traffic over several paths.
• Performance Comparison: Equate the STP including other protocols such as RSTP (Rapid Spanning Tree Protocol).

Complete MATLAB Code Example

Below is an integrated STP simulation:

% Define adjacency matrix

adjMatrix = [

0 1 3 0;

1 0 1 4;

3 1 0 2;

0 4 2 0

];

% Define bridge IDs

bridgeIDs = [2, 1, 3, 4];

% Compute the spanning tree

spanningTree = computeSpanningTree(adjMatrix, bridgeIDs);

% Display the spanning tree

disp(‘Spanning Tree Adjacency Matrix:’);

disp(spanningTree);

% Visualize the network and spanning tree

G = graph(adjMatrix, ‘upper’);

G_spanning = graph(spanningTree, ‘upper’);

plot(G, ‘EdgeLabel’, G.Edges.Weight);

highlight(plot(G_spanning), ‘EdgeColor’, ‘r’, ‘LineWidth’, 2);

title(‘Spanning Tree Visualization’);

% Supporting Function

function spanningTree = computeSpanningTree(adjMatrix, bridgeIDs)

numNodes = size(adjMatrix, 1);

% Step 1: Elect the Root Bridge

[~, rootBridge] = min(bridgeIDs);

% Initialize variables

pathCost = inf(1, numNodes);

pathCost(rootBridge) = 0;

rootPorts = -ones(1, numNodes);

visited = false(1, numNodes);

% Step 2: Compute Path Costs

for i = 1:numNodes

[~, u] = min(pathCost + visited * inf);

visited(u) = true;

neighbors = find(adjMatrix(u, 🙂 > 0);

for v = neighbors

cost = pathCost(u) + adjMatrix(u, v);

if cost < pathCost(v)

pathCost(v) = cost;

rootPorts(v) = u;

end

end

end

% Step 3: Build the Spanning Tree

spanningTree = zeros(numNodes);

for v = 1:numNodes

if rootPorts(v) > 0

spanningTree(v, rootPorts(v)) = adjMatrix(v, rootPorts(v));

spanningTree(rootPorts(v), v) = adjMatrix(rootPorts(v), v);

end

end

enD

Conclusion

This project offers a basic approach to replicate and estimate the Spanning Tree Protocol (STP) using MATLAB. We are ready to explore further aspects such as dynamic link changes or Rapid STP enhancements.