At the beginning of stanza 3, Tennyson repeats the word cannon three times as follows:
Cannon to right of them,
Cannon to left of them,
Cannon in front of them.
The repetition of the same word at the beginning of consecutive lines of a poem is a literary device called anaphora
. The repetition creates a soothing sense of rhythm, but more importantly, it draws emphasis to a particular word. Hearing "cannon" three times in a row this way amplifies the extent to which cannons surround the soldiers of the Light Brigade on all sides. Making extremely clear that the cannons are to the left, right, and front of the men creates a threatening spatial image that highlights that the soldiers and their horses are hemmed in on all sides as they charge. Readers can thus see in their mind's eye how the cavalry truly is walking into the "jaws of Death."
The verses about the cannon become a refrain as they are repeated at the beginning of stanza five, emphasizing that it was impossible for the Light Brigade to emerge from battle without huge losses. We note in stanza five that very few of the 600 men come back from the battle. The focus on the cannons accentuates the heroism of the soldiers, who rode bravely into almost certain death.