▁relationship . ▁In ▁a ▁mult il ater al ▁feder ation , ▁the ▁metadata ▁exchange ▁among ▁participants ▁is ▁a ▁more ▁complex ▁issue . ▁It ▁can ▁be ▁handled ▁in ▁a ▁hub - and - sp oke ▁exchange ▁or ▁by ▁the ▁distribution ▁of ▁a ▁metadata ▁aggregate ▁by ▁a ▁feder ated ▁operator . ▁ ▁One ▁thing ▁that ▁is ▁consistent , ▁however , ▁is ▁the ▁fact ▁that ▁" f eder ation " ▁describes ▁methods ▁of ▁identity ▁port ability ▁which ▁are ▁achieved ▁in ▁an ▁open , ▁often ▁standards - based ▁manner ▁– ▁meaning ▁anyone ▁ad her ing ▁to ▁the ▁open ▁specification ▁or ▁standard ▁can ▁achieve ▁the ▁full ▁spectrum ▁of ▁use - cases ▁and ▁inter oper ability . ▁ ▁Identity ▁feder ation ▁can ▁be ▁accomplished ▁any ▁number ▁of ▁ways , ▁some ▁of ▁which ▁involve ▁the ▁use ▁of ▁formal ▁Internet ▁standards , ▁such ▁as ▁the ▁O AS IS ▁Security ▁Assert ion ▁Mark up ▁Language ▁( SA ML ) ▁specification , ▁and ▁some ▁of ▁which ▁may ▁involve ▁open - source ▁techn ologies ▁and / or ▁other ▁open ly ▁published ▁specific ations ▁( e . g . ▁Information ▁C ards , ▁Open ID , ▁the ▁H igg ins ▁trust ▁framework ▁or ▁Nov ell ’ s ▁Band it ▁project ). ▁ ▁Techn ologies ▁Techn ologies ▁used ▁for ▁feder ated ▁identity ▁include ▁SA ML ▁( Security ▁Assert ion ▁Mark up ▁Language ), ▁O Auth , ▁Open ID , ▁Security ▁Tok ens ▁( Simple ▁Web ▁Tok ens , ▁JSON ▁Web ▁Tok ens , ▁and ▁SA ML ▁assert ions ), ▁Web ▁Service ▁Spec ifications , ▁and ▁Windows