Aside from the discussion in the Mishna with regard to the height of a sukka, there is also a need to define the minimum size of a sukka. The Gemara on our daf presents a discussion between Beit Hillel and Beit Shammai, in which they agree that it must be large enough to fit a person’s head and the majority of his body (rosho ve-rubo), but they disagree on whether there is cause for concern that he will lean out of the sukka if the table is placed outside. According to Beit Hillel this is not something that we fear will happen; so as long as rosho ve-rubo fit, the sukka is fine. Beit Shammai rules that this is a concern, so we must make the sukka large enough to contain the table, as well.
Another opinion quoted is that of Rabbi Yehuda HaNasi, who believes that the sukka must be four cubits by four cubits.
This discussion leads the Gemara to quote a baraita that limits the significance of buildings smaller than four by four amot. Among other things, such a structure would not need a mezuza, nor could it be used to house the eiruv that permits carrying between houses or courtyards, or to connect two nearby cities to one another for the purposes of permitting travel between the two on Shabbat (eiruv hatzerot). In this way, the Gemara points out that such a small building does not even have the status of burganin.
Burganin are booths used by watchmen on the roads. Some of them were well constructed and were used as defensive positions for the military. The guards lived in these structures, guarded the fields and delivered reports and messages to the government. Other burganin were poorly made and were no more than shacks on the side of the road. The source for the word burganin may be Greek in origin, but it is likely from the German “Burg” meaning “fortress” or “small settlement.” The term was carried on the lips of Roman soldiers who were stationed on the border with Germany throughout the Roman Empire – even to the language of the Talmudic Sages.
The significance of these structures for Jewish law relates to the fact that, on Shabbat, a person is limited in his ability to travel more than 2,000 amot outside of his city. When deciding where the edge of the city lies, however, if they are close enough (about 70 amot) to the city, buildings like these can be considered part of the city, thus allowing one to walk significantly further away from the city limits on Shabbat.