Introduction to Pro Tools : Pro Tools Concepts : Embedded Media and Linked Media : Linked Media

Linked Media
Exporting AAF or OMF with linked media results in a single metadata file (.AAF or .OMF) and allassociated media stored as separate files.
The main benefit to this approach is that fewer copies of media files may need to be made, so the export and import process can be much faster. Using this approach, it is less likely that you will encounter any file size limitations since the data is broken up into many smaller files.
The main disadvantage to this approach is that there are potentially many files (for example, one AAF or OMF file and hundreds of media files) that must be transported between systems.