When a channel is opened with a conformational switch, it is open to both environment simultaneously (extracellular and intracellular); channels are either in open state or closed state.
Pores are continuously open to these both environment, because they do not undergo conformational changes They are always open.
Pathway in a carrier protein is not open smiltaneously to the both environment. Either its inner gate is open, or outer gate is open, or both gates are closed.
Carrier has binding sites, but porins and channel proteins have not.