Jamieson, Fausset and Brown on 2 Kings 18:17

17. king of Assyria sent Tartan--general (Is 20:1).

Rab-saris--chief of the eunuchs.

Rab-shakeh--chief cupbearer. These were the great officers employed in delivering Sennacherib's insulting message to Hezekiah. On the walls of the palace of Sennacherib, at Khorsabad, certain figures have been identified with the officers of that sovereign mentioned in Scripture. In particular, the figures, Rab-shakeh, Rab-saris, and Tartan, appear as full-length portraits of the persons holding those offices in the reign of Sennacherib. Probably they represent the very individuals sent on this embassy.

with a great host to Jerusalem--Engaged in a campaign of three years in Egypt, Sennacherib was forced by the king of Ethiopia to retreat, and discharging his rage against Jerusalem, he sent an immense army to summon it to surrender. (See on 2Ch 32:30).

the conduit of the upper pool--the conduit which went from the reservoir of the Upper Gihon (Birket et Mamilla) to the lower pool, the Birket es Sultan.

the highway of the fuller's field--the public road which passed by that district, which had been assigned them for carrying on their business without the city, on account of the unpleasant smell [Keil].