Radia Perlman's pivotal 1985 paper "An algorithm for distributed computation of a spanningtree in an extended LAN"<p><a href="http://www1.cs.columbia.edu/~ji/F02/ir02/p44-perlman.pdf" rel="nofollow">http://www1.cs.columbia.edu/~ji/F02/ir02/p44-perlman.pdf</a><p>More papers should have their algorithms in rhyme!<p><pre><code>  Algorhyme

  I think that I shall never see 
  A graph more lovely than a tree

  A tree whose crucial property 
  Is loop-free connectivity.

  A tree which must be sure to span 
  So packets can reach every LAN.

  First the Root must be selected 
  By ID it is elected.

  Least cost paths from Root are traced. 
  In the tree these paths are placed

  A mesh is made by folks like me 
  Then bridges find a spanning tree.</code></pre>