Better explanation of the JP Morgan trade

http://online.wsj.com/article/BT-CO-20120515-721495.html

JP Morgan's USD2 Billion-Plus Loss Came On Three-Legged Trade

   By Katy Burne

   Of DOW JONES NEWSWIRES

NEW YORK (Dow Jones) -- The complex web of trades that saddled J.P. Morgan Chase & Co. (JPM) with at least $2 billion in losses had three key components, according to people familiar with the bank's strategy. 

So the three legs of the trade were
(1) buy protection on junk bonds expiring ?
(2) sell huge amounts of CDX IG9 expiring 2017
(3) buy protection on investment grade bonds expiring at the end of 2012

I am still not sure I understand what they were doing exactly.  Apparently neither did they.