Switched Multimegabit Data Service (SMDS)

• Switching service that provides data transmission in the range between 1.544 Mbps (T1 or DS1) to 45 Mbps (T3 or DS3).
• Connectionless service that, like ATM, uses fixed-length 53 bytes cells.
• Like ATM and frame relay, it provides no error checking, leaving that up to devices at the connection points.
• IEEE 802.6 (MAN) specification.
• is a dual bus topology that forms a ring that is not closed