In 1936, in "Les Hittites" during the evocation of the conflicts between the Hittites and the Mitanni Hourri, Louis Delaporte writes that Suda is the town of Sada, now Ünsalli in Turkey, located 31 kilometers north Nisibis (Nusaybin).
The text KB0 III 60 of Hattusa archive evokes a Hittite expedition from Nuhayana against Halab and Ilan-Sura. It speaks of cannibals, of a prince of Suda and of the cities of Surra and Ukapuwa. The text KUB XXIII 102 is even more interresting about the location of Suda / Sudu "I conquered and destroyed the city of Irridu. The great gods have given me to govern all the countries of Taidu to Irridu and Eluhut, with all Kashiari Mountains, the fortresses of Sudu and Harranu to the bank of the Euphrates. "
Suda is extensively mentioned in the archives of Mari, here are the most significant letters on geography :
IV 40: "The company is departed from Suda. Urkish and Sinah, I will take them by force ... "
I 19 "I had written you about a possible move from Nihriya to Suda. In fact, I've changed my mind. The enemy would learner the following assumption: "They head inside the Yapturum". That's what he would say. [...] "
I 97: "Mount Hasam is at 2 double miles from Subat-Samas. We need two lightly equipped servants, for taking your tablets and, at night, for running inside the Hasam without be seen, they must earning Suda or Mammagira".
Mount Hasam is also mentioned, under the title of "Mountain of Hasamu" in the archives of Shalmaneser III, a neo-Assyrian king, on the road to Til-Barsip: "I crossed the Tigris, through the mountains Hasamu and Dihnunu, for going to Til-Barsip.". So this moutain is a southwest branch of Turabdin, as proposed by Jean-Marie Durand in "epistolary documents of the palace of Mari."
We can conclude that by "Suda" the Mari texts refer to the same city as the archives of Hattusa. It was a city of Mitanni. Sada, now called Ünsalli, is a serious candidate for ancient town, although no archaeological excavation comes to supporting this hypothesis.
My notes of veracity :
Suda, Sada was the present city of Ünsalli in Turkey: 3/5