T3 and DS3 are terms which in the field of telecommunication are often used interchangeably to describe a 45 mbps (megabits per second) circuit. A T3-DS3 is the equivalent of 28 T1s. People who are more technically inclined will often refer to DS3 when they are talking about the configuration of the circuit, and T3 if they are referring to the physical facilities which carry the circuit. Most people, however, use both terms interchangeably.T3 is a relatively large data bandwidth pipe which is commonly used for internet connectivity, voice lines, direct point-to-point connection between two business locations, Multiprotocol Label Switching (MPLS) networking between multiple locations of a business and integrated circuits which combine any combinations of these applications.
DS3 MPLS networks are better suited for networking more than two locations than point-to-point circuits. This is because MPLS facilitates any-to-any location networking rather than requiring a separate circuit for each two locations required by point-to-point networks. Also, with Class of Service (CoS) MPLS can prioritize applications. With CoS, applications such as routine data transfer, voice, and video can be efficiently implemented simultaneously over one bandwidth pipe, without interfering with each other. MPLS is a major advancement when compared networks based on point-to-point or frame relay.