get9 / LANSpan

A simple implementation of the LAN spanning tree algorithm for IEEE 802.1 networks

LANSpan

A bridge network minimum spanning tree implementation

What works

From walking through the algorithm as presented in class, on the slides, and working the example provided in the textbook, I believe this produces the correct output for the given sample input file.

Output notation

The output displayed is comprised of the following:

1. Sequence of actions (messages sends/receives) and appropriate actions taken by each bridge upon processing a message
2. Output of the network state at the end of the sending sequence. The output is as follows:

  id = <Bridge ID>
      Link1 (best config) [STATUS]
      Link2 (best config) [STATUS]
      ...
      LinkN (best config) [STATUS]
  id = <Bridge ID>
      ...

The [STATUS] after each link's best config indicates the status of that link after executing all sends/receives. If the link is closed after execution, it will be denoted with a [CLOSED] status. If the link remains open after execution, the status will be blank.

Limitations

In the implementation, what I feel is a limitation is that in order to get around the problem of the bridges immediately connected to LANs around the root node from disabling their links back to the root node when the root sends a second configuration message, I had to add an explicit check in src/bridge.cpp for if the message was sent from the root node, don't close any links. I'm not sure if this generalizes well to other sample inputs.

Building and running the code

The general steps to build and run the code are as follows:

1. cd /path/to/unzipped/directory
2. cd src/
3. make
4. ./myprogram <inputfile> <send order separated by spaces>