3Com WL-603 User Manual page 85

VBR (variable bit rate): QoS class defined by the ATM Forum for
■
ATM networks. VBR is subdivided into a real time (RT) class and
non-real time (NRT) class. VBR (RT) is used for connections in which
there is a fixed timing relationship between samples. VBR (NRT) is
used for connections in which there is no fixed timing relationship
between samples, but that still need a guaranteed QoS. Compare
with ABR, CBR, and UBR.
UBR (unspecified bit rate): the UBR service class is intended for
■
delay-tolerant or non-real-time applications, for example, those
which do not require tightly constrained delay and delay variation,
such as traditional computer communications applications. The
UBR service may be considered as "best effort service".
6 PCR/SCR/MBS: PCR (Peak Cell Rate), SCR (Sustainable Cell Rate) and MBS
(Maximum Burst Size) are configurable.
7 Click Apply.
Internet Settings 83