One of the radical changes that have occurred in current IP networks has been the migration from IPv4 to IPv6. One of the most important aspects of the IPv6 protocol is the fact that allows the labeling of packets belonging to a particular flow in order to give proper treatment by routers, for such purpose, the "Flow Label" field was originally created. However, this field has not been exploited yet and it has even been shelved due to the rise of other technologies such as MPLS. With the rise of IPv6 world implementation, it is essential to know the requirements of the use of this field to exploit the functions for which it was created. This article describes the IPv6 flow label field evolution, specifications and recommendations published by the IETF to use it; also here, some approaches are described, which have been proposed so far using the Label Flow for different purposes.