Probably, this question could be at https://math.stackexchange.com/, but, for some reason, I can't access that site right now. So, I apologize in advance.

At this article http://arxiv.org/ftp/math/papers/0303/0303175.pdf , page 4, last diagram, professor Ross Street says that the Descent Category (as defined by him) of the truncated cosimplicial category is, in someway, analogue to the equalizers.

I assumed that he is talking about 2-limits (since, if he were talking about 1-limits, the limit analogue to pullback would be the pulback itself). Am I right?

(1) If I am right, I wonder if the Descent Category, defined by him, is the 2-limit of that truncated cosimplicial category. If it is not true, why is the descent category defined by him related to the 2-limits/limits?

(2) I would like to know where I can find texts on n-limits. Which would be the best way to understand it?