The narrator is a person who tells the story. Narrators can be divided into three categories; First person narrator, Second person narrator and Third person narrator. FIRST PERSON narrator is an "I", who speaks from her/his subject position This narrator is usually a character in the story, who interacts with other characters; we see those interactions through the narrator's eyes, and we can't know anything the narrator doesn't know. SECOND PERSON narrator speaks in "you." a THIRD PERSON narrator is not a figure in the story, but an "observer" who is outside the action being described. A third-person narrator might be omniscient (ie, able to tell what all the characters are thinking), but that is not always the case. Third-person narration may also be focalized through a particular character, meaning that the narrator tells us how that character sees the world, but can't, or at least doesn't, read the mind of all the characters this way.
We find Trollope as a narrator in Barchester Towers adopting various techniques from different type of narrators such as he is the `intrusive' narrator, who is made a part of the world of Barchester. His presence is very much felt as an intrusive when he commented on Dr. Grantly in "Who will be the new Bishop" and raises a personal view point; "our archdeacon was worldly- who among us is not?" He is also an `omniscient' narrator which falls in the sub category of third person narrator like in the chapter "War" he pronounced Grantly's viewpoint about the bishop Proudie "he was a puppet to be played by others; a mere wax doll..." . He is present every where in the novel; commenting, telling and giving description of each and every turning point of the novel.
Trollope disrupts conventional uses of suspense by building it up and then taking it away by revealing the truth through interrupting the narrative, which is however unexpected. An example of this is when the narrator suddenly informs in chapter "The widow's suitor" that "It is not destined that Eleoner shall marry Mr. Slope or Bertie Stanhope", destroying some suspense, however still maintaining the curiosity with whom she will marry.
Trollope as narrator forefronts while giving detail descriptions of character's background and sketching full life of new individual in Barchester Towers for the reader. For example in chapter "Dr and Mrs. Proudie" he starts with the introduction of new situation as Dr. Proudie had become the new bishop, he gave brief description of his Episcopal ceremony and then continues with the character details, presenting full picture with minor details of Dr. Proudie as an individual.
On contrary there is also the dominating impression that the author talks too much in the novel. He digresses at length on women, tradesman, farmers' etc. Some of this chattiness is richly informative as Victorian Morses and manners. It reflects Trollope's great observation but on other hand it also tends to get bore at times and the reader...