We　present　a　simplistic　yet　accurate　unit　cell　model　of　sound　absorption　for　highly　porous　foams　having　either　fully-open　or　semi-open　cells.　Employing　an　idealized　periodic　cubic　unit　cell　to　mimic　the　foam　topology,　we　establish　an　analytical　model　for　predicting　the　sound　absorption　coefficient　of　the　foam.　Analytical　links　between　key　non-acoustic　parameters　(viscous　permeability　and　flow　tortuosity)　and　cellular　topological　characteristics　are　also　established.　For　fully-open　foams,　the　model　requires　only　two　morphological　parameters,　porosity　and　pore　window　size,　significantly　reducing　the　complexity　of　sound　transport　modeling.　For　semi-open　foams,　an　additional　parameter,　open-pore　rate　representing　the　influence　of　thin　membrane　covering　on　pore　window,　is　introduced.　The　analytical　model　predictions　are　compared　with　existing　experimental　data　and　numerical　simulation　results　for　polyurethane　foams,　with　good　agreement　achieved.　(C)　2015　Elsevier　Ltd.　All　rights　reserved.