Answering Christianity Research Center

Assalamualaikum brothers! Well i'm a bit confused right now.I was recently reading something on Answering Christianity and i found it was written somewhere on the article that i was reading that the Edomites were Arabs or in other words Ishmaelites.On the other hand i read on a Christian website that the Edomites were among the children of Esau the son of Isaac.So who were the Edomites? Arabs or something else?