Answer:
Tennyson most likely repeats the word "cannon" in the first three lines of the excerpt to show that the assault on the soldiers was nonstop. By repeating the word "cannon," Tennyson emphasizes the constant barrage of artillery fire the soldiers faced from all sides. This repetition creates a sense of overwhelming and relentless attack, highlighting the danger and intensity of the battle. It also underscores the bravery and resilience of the soldiers who faced such a relentless onslaught.