Megillah, Chapter 1, Mishnah 10. This mishnah deals with the concept of the bamah. During the time the Mishkan stood in Shiloh, and likewise during the time the Beis HaMikdash stood in Jerusalem, it was forbidden to offer sacrifices anywhere else. However, in the period before Shiloh, and also in the period between the Mishkan of Shiloh and Jerusalem, it was permitted to offer sacrifices in a place called a bamah - a raised, elevated place upon which the offering was brought.
Two types of bamos:
A large bamah - any place where the Mishkan was set up, even temporarily, such as in Gilgal, in Nov and in Givon. This was the public site for bringing offerings on behalf of all Israel.
A small bamah - a private bamah, which any person was permitted to build out of stone and to bring an offering upon.
The words of the mishnah:
"Ein bein bamah gedolah l'vamah ketanah ela Pesachim" - there is no difference between the large public bamah, such as the one in Gilgal, in Nov and in Givon, and the small private bamah, except with regard to the Pesach offering alone: the Pesach offering was brought on a large bamah and not on a small bamah.
The Gemara explains that this is not limited to Pesach offerings specifically, but applies to every obligatory offering that has a fixed time, like the Pesach - such as the daily temidim and the musaf offerings. These offerings are brought on a large bamah and not on a small bamah.
By contrast, there are obligatory offerings that do not have a fixed time, such as the bull brought for an erroneous ruling of the community, which comes when the court issued a mistaken ruling. These offerings were not brought even on a large bamah, but only in the Mishkan or in the Beis HaMikdash.
"Zeh haklal":
The mishnah sums up and establishes a rule: "Kol shehu nidar v'nidav - karev bevamah". Any offering that can be brought as a vow, meaning that a person verbally obligates himself to bring an offering, or as a free-will gift, in which he designates a particular animal as an offering - these are voluntary offerings, and they are brought on a bamah, and the reference here is to a small bamah, a private bamah.
And on the other hand: "V'chol she'eino lo nidar v'lo nidav" - an offering that cannot come as a voluntary offering, but is rather an obligatory offering, is not brought on a bamah, but only in the Mishkan and in the Beis HaMikdash.
In summary: in this mishnah we learned the difference between a large bamah, the public bamah at the site of the Mishkan, and a small bamah, the bamah of an individual. The only difference between them concerns obligatory offerings that have a fixed time, such as the Pesach, the temidim and the musaf offerings, which are brought only on a large bamah; whereas obligatory offerings that have no fixed time are not brought on a bamah at all. The rule that emerges from the mishnah: whatever can be brought as a vow or a free-will gift is brought on a bamah, and whatever cannot be brought as a vow or a free-will gift is brought only in the Mishkan and in the Beis HaMikdash.