AirLive ARM-204 User Manual
Page 34
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ATM VC
Parameter
Description
Virtual Circuit
VPI (Virtual Path Identifier) and VCI (Virtual Channel
Identifier define a virtual circuit.
VPI
VPI is a virtual path determines the way an ATM cell
should be routed. The VPI is an 8-bit (in UNI) or 12-bit (in
NNI) number that is included in the header of an ATM
cell. The valid range for the VPI is 0 to 255. Enter the VPI
assigned by the ISP.
Parameter
Description
VCI
VCI is the label given to an ATM VC to identify it and
determine its destination. The VCI is a 16-bit number that
is included in the header of an ATM cell. The valid range
for the VCI is 32 to 65535. Enter the VCI assigned by the
ISP.
ATM QoS
CBR (Constant Bit Rate) – This class is used for
emulating circuit switching. The cell rate is constant with
time. Select CBR to specify fixed (always on) bandwidth
for voice or data traffic.
UBR (Unspecified Bit Rate) – Select UBR for applications
that are non-time sensitive, such as e-mail.
rtVBR (real time Variable Bit Rate) – This class is similar
to nrtVBR but is designed for applications that are
sensitive to cell-delay variation. Examples for real-time
VBR are voice with speech activity detection (SAD) and
interactive compressed video.