I think it is the verb. Because the verb represents an action or a state of being.
Simile
when using like or as to compare it is a simile
The effect that the structure of the lines in the poem "Ulysses" has is it gives the poetic piece depth. This gives the reader something to ponder while reading the literary piece. It also has an effect on the reader's understanding of the poem, this creates a variation of analysis for each reader.