What is internal trade ? State its important features

What is internal trade ? State its important features.
Or
What is meant by internal trade

When buying and selling of goods and services take place within a country, it is referred to as internal trade.
Some of the important features of internal trade are
(i) All payment are made in the national currency.
(ii) Generally there are no restrictions on the movements of goods.
(iii) Several alternative modes of transport are available for carrying goods.