Aspects of the subject disclosure may include, for example, a transmission device that includes a transmitter that generates a first electromagnetic wave to convey data, the first electromagnetic wave having at least one carrier frequency and corresponding wavelength. A coupler couples the first electromagnetic wave to a transmission medium having at least one inner portion surrounded by a dielectric material, the dielectric material having an outer surface and a corresponding circumference, wherein the coupling of the first electromagnetic wave to the transmission medium forms a second electromagnetic wave that is guided to propagate along the outer surface of the dielectric material via at least one guided-wave mode that can include an asymmetric mode, wherein the at least one carrier frequency is within a microwave or millimeter-wave frequency band and wherein the at least one corresponding wavelength is less than the circumference of the transmission medium. Other embodiments are disclosed.