In SDH and SONET standards, group of Virtual Tributaries (VT), each of which carries the same form of signal (e.g., DS-1, DS-2, or DS-3) within a byte-interleaved frame. SONET can map as many as four VTs into a VTG, and as many as seven VTGs into a single Virtual Path (VP). See also DS-1, DS-2, DS-3, SDH, signaling rate, SONET, and VT.