Who gave the suggestion of digging the trench around the city of Madinah at the time of Battle of Khandaq?

Salman al-Farsi suggested digging a trench around Madinah during the Battle of Khandaq, a tactic he learned from Persian warfare that was unknown to the Arabs at the time. Prophet Muhammad approved the idea, and he and his companions worked together to dig a large trench on the northern side of the city, which was the only side not protected by natural terrain like mountains and forests.