A simplified, distributed version of the Spanning Tree Protocol (STP) for arbitrary layer 2 topologies. STP can be used to prevent forwarding loops on a layer 2 network.
switch.py represents a layer 2 switch that implements STP.
run_spanning_tree.py loads a topology file (e.g. SimpleLoopTopo.py) and uses that data to create a Topology object containing Switch objects before starting the simulation. The final spanning tree is written to a file placed in the Logs folder.
Syntax: python run_spanning_tree.py <topology_file> <log_file>
When making topology files, remember the following:
- All switch IDs should be unique, positive integers.
- There is a single, distinct solution for each topology.
NB: If there are two paths of equal distance to the same root, then:
the switch will choose the path through the neighbour with the lowest switch ID. - All switches in the network must be connected to at least one other switch, and all switches must be able to reach every other switch.
- This STP does not consider redundant links, so there should only be 1 link between each pair of directly connected switches.