WAN and System Configuration 2-7
VBR: This class is characterized by:
• a Peak Cell Rate (PCR), which is a temporary burst, not a sustained rate, and
• a Sustained Cell Rate (SCR),
• a Burst Tolerance (BT), specified in terms of Maximum Burst Size (MBS). The MBS is the maximum
number of cells that can be transmitted at the peak cell rate and should be less than, or equal to the
Peak Cell Rate, which should be less than, or equal to the line rate.
VBR has two sub-classes:
a. VBR non-real-time (VBR-nrt): Typical applications are non-real-time traffic, such as IP data traf fic.
This class yields a fair amount of Cell Delay Variation (CDV).
b. VBR real time (VBR-rt): Typical applications are real-time traffic, such as compressed voice over IP
and video conferencing. This class transmits cells with a more tightly bounded Cell Delay Variation.
The applications follow CBR.
•Then, select a Connection Profile for the Circuit. To use the Default Profile, select Use Default Profile
for Circuit and press Return. For other options, select a profile from the Use Connection Profile
pop-up menu.
Add Circuit
Circuit Name: Circuit 2
Circuit Enabled: Yes
Circuit VPI (0-255): 0
Circuit VCI (32-65535): 32
QoS... VBR
Peak Cell Rate (0 = line rate): 0
Sustained Cell Rate: 0
Maximum Burst Size: 0
Use Connection Profile... Default Profile
Use Default Profile for Circuit
ADD Circuit NOW CANCEL
Return accepts * ESC cancels * Left/Right moves insertion point * Del deletes.