Unspecified bit rate (UBR)
	No QoS requirements (i.e. ”best effort” service). The only traffic parameter of interest is the PCR which the user is not allowed to exceed. UBR supports a high degree of statistical multiplexing. Typical applications: -  File transfer (non-critical applications) -  E-mail
				(Guaranteed Frame Rate = GFR)
		(This is a new service category defined in the ATM Forum Traffic Management Specification Version 4.1)