▁systems ▁integration ▁where ▁each ▁system ▁is ▁inter connected ▁to ▁each ▁of ▁the ▁remaining ▁sub system s . ▁When ▁observed ▁from ▁the ▁perspective ▁of ▁the ▁sub system ▁which ▁is ▁being ▁integrated , ▁the ▁connections ▁are ▁rem in is cent ▁of ▁a ▁star , ▁but ▁when ▁the ▁overall ▁diagram ▁of ▁the ▁system ▁is ▁presented , ▁the ▁connections ▁look ▁like ▁sp agh etti , ▁hence ▁the ▁name ▁of ▁this ▁method . ▁The ▁cost ▁var ies ▁because ▁of ▁the ▁interfaces ▁that ▁sub system s ▁are ▁export ing . ▁In ▁a ▁case ▁where ▁the ▁sub system s ▁are ▁export ing ▁heter ogeneous ▁or ▁propriet ary ▁interfaces , ▁the ▁integration ▁cost ▁can ▁substantial ly ▁rise . ▁Time ▁and ▁costs ▁needed ▁to ▁integrate ▁the ▁systems ▁increase ▁expon entially ▁when ▁adding ▁additional ▁sub system s . ▁From ▁the ▁feature ▁perspective , ▁this ▁method ▁often ▁seems ▁prefer able , ▁due ▁to ▁the ▁extreme ▁flex ibility ▁of ▁the ▁reuse ▁of ▁functionality . ▁ ▁Hor izontal ▁integration ▁or ▁Enter prise ▁Service ▁Bus ▁( E SB ) ▁is ▁an ▁integration ▁method ▁in ▁which ▁a ▁special ized ▁sub system ▁is ▁dedicated ▁to ▁communication ▁between ▁other ▁sub system s . ▁This ▁allows ▁cutting ▁the ▁number ▁of ▁connections ▁( inter faces ) ▁to ▁only ▁one ▁per ▁sub system ▁which ▁will ▁connect ▁directly ▁to ▁the ▁E SB . ▁The ▁E SB ▁is ▁capable ▁of ▁transl ating ▁the ▁interface ▁into ▁another ▁interface . ▁This ▁allows ▁cutting ▁the ▁costs ▁of ▁integration ▁and ▁provides ▁extreme ▁flex ibility . ▁With ▁systems ▁integrated ▁using ▁this ▁method , ▁it ▁is ▁possible ▁to ▁completely ▁replace ▁one