Referring to a field in the Internet Protocol version 4 (IPv4) header that indicates the quality of service (QoS) requested for the datagram. Although TCP/IP networks currently do not provide guaranteed QoS, the networks will attempt to honor QoS requests in terms of parameters that include packet precedence (i.e., priority), low delay, high throughput, and high reliability. See also datagram, DiffServ, header, IPv4, QoS, and TCP/IP.
(1) See terms of service.
(2) (Type Of Service) A field in an IP packet (IP datagram) that is used for quality of service (QoS). The TOS field is 8 bits, broken into five subfields.
(3) (Tape Operating System) An OS for IBM's System/360 Model 30 in the mid-1960s. It was superseded by DOS/360.