A quality of service defined by the ATM Networks/ATM Forum, allowing any amount of data up to a set maximum to be sent across a network; non-time sensitive data that could be retransmitted without significant inconvenience. Does not guarantee freedom from delay or cell loss.
UBR) UBR is an ATM quality of service category. It is used for applications that do not require loss and delay guarantees, such as Internet access and email where delays can be tolerated. In a UBR connection bandwidth is allocated after all other service requirements have been met.