In this question, you say that agents of globalization include mass culture, trade, migration, and communications. All of these things existed in past centuries. Let us look at a few examples. The United Kingdom was trading with India 300 years ago. There was migration from Germany and Ireland to the United States in the 1840s. The first cable to link North America to Europe by telegraph was completed in 1858. All of these things helped to create globalization.
However, these agents of globalization work faster and on a larger scale today. Instead of communicating by telegraph between stations, we communicate by internet or telephone directly with one another. Instead of having trade or migration that goes by sailing ship, we now use airplanes or much larger and faster ships than in times past. Our mass culture is disseminated across many countries very quickly through movies, TV, and the internet.