The PON specification described by the ITU-T in G.984 (2004), GPON operates in both asymmetric and symmetric configurations, and currently supports signaling rates as high as 2.488 Gbps with a maximum logical reach of approximately 60 kilometers (37 miles). GPON supports as many as 32 or 64 splits, that is, splitters can divide the signal to serve as many as 32 or 64 premises from a single optical fiber, and expectations are that as many as 128 splits will be supported in the future.At full speed of 2.488 Gbps with the current maximum of 64 splits, each premises has access to sustained bandwidth of more than 35 Mbps, which is far beyond that offered by other access technologies. GPON supports voice, data, and video in ATM format. GPON also supports voice in native PCM/TDM format and data in Ethernet format, and employs wavelength division multiplexing (WDM) for downstream transmission. GPON specifies advanced encryption standard (AES) to secure downstream transmissions. PON variants also include ATM-based PON (APON), broadband PON (BPON), and Ethernet-based PON (EPON). See also AES, APON, asymmetric, ATM, bandwidth, BPON, EPON, Ethernet, ITU-T, logical reach, optical fiber, PCM, PON, splitter, symmetric, and TDM.