Role based training refers to training the is customized to the specific role that employee holds in the organization.
For example, a salesperson may be required to attend a program that is specfically geared to designing and delivering presentation on the specificiations of the product line, as a opposed to a "generic" presentation skills course.
Typically companies that provide RBT, consult with the organization to have a full appreciation for the skills and comps required in a role within the organization.
Another example would be to train call center personnel in a customized manner depending on whether their role is input or outbound calls, sales or customer service, etc.
Hope that helps