UBR

unspecified bit rate

UBR is an ATM service category that is used for applications, which do not require guarantees of low cell loss or low delay. Specifically, UBR does not include the notion of a per-connection negotiated bandwidth. No numerical commitments are made with respect to the cell loss ratio experienced by a UBR connection, or as to the cell transfer delay experienced by cells on the connection. UBR emulates the connectionless services provided by conventional bridged and routed data networks. It provides best effort delivery.