Which type of passive optical network (PON) access architecture replaced asynchronous PON (APON)?

The correct response indicates that Gigabit-capable PON (GPON) is the architecture that replaced asynchronous PON (APON). GPON represents a significant advancement over APON, primarily in terms of performance and capacity. While APON supported lower bit rates and was limited in the amount of bandwidth it could efficiently provide to subscribers, GPON upgrades this to gigabit speeds, allowing for faster data transmission and improved service offerings.

One of the key features of GPON is its ability to support multiple types of services (such as voice, data, and video) over a single network, enhancing flexibility and efficiency for service providers. GPON also incorporates advanced technologies for data encapsulation and transport, which contribute to its enhanced efficiency compared to APON.

Other architectures listed, such as Ethernet PON (EPON) and Next-generation PON (NG-PON), represent different approaches or further developments in passive optical networks but do not specifically succeed APON in the same direct manner as GPON. Time Division PON (TD-PON) is more of a conceptual framework rather than a direct successor to APON. Thus, GPON is the critical evolution that addresses the limitations of APON while driving higher speed and service convergence.