Cerberus P 6331-4A
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ATM
VC
ATM settings are used to connect to your ISP. Your ISP provides VPI, VCI, settings to
you. In this Device, you can totally setup 8 PVCs on different encapsulations if you apply
8 different virtual circuits from your ISP. You need to activate the VC to take effect. For
PVCs management, you can use ATM QOS to setup each PVC traffic line’s priority.
Virtual Circuit
– Select the VC number you want to setup.
Status
– Select whether selected connection is
Activated
or
Deactivated
.
VPI
– Virtual Path Identifier. The valid range for the VPI is 0 to 255.
VCI
– Virtual Channel Identifier. The valid range for the VCI is 1 to 65635 (0 to 31 is
reserved for local management of ATM traffic).
ATM QoS
– Select the Quality of Service types for this Virtual Circuit. The ATM QoS
types include
CBR
(Constant Bit Rate),
VBR
(Variable Bit Rate) and
UBR
(Unspecified
Bit Rate). These QoS types are all controlled by the parameters specified below,
including PCR, SCR, and MBS.
PCR (Peak Cell Rate)
– Peak Cell Rate (PCR) is the maximum rate at which the sender
can send cells. This parameter may be lower (but not higher) than the maximum line
speed. 1 ATM cell is 53 bytes (424 bits), so a maximum speed of 832 Kbps gives a
maximum PCR of 1962 cells/sec. This rate is not guaranteed because it is dependent on
the line speed.
SCR (Sustained Cell Rate)
– Sustained Cell Rate (SCR) is the mean cell rate of a burst,
on-off traffic source that can be sent at the peak rate, and a parameter for burst-type
traffic. SCR may not be greater than the PCR; the system default is 0 cells/sec.
MBS (Maximum Burst Size)
– Maximum Burst Size (MBS) is the maximum number of
cells that can be sent at the PCR. After MBS is reached, cell rates fall below SCR until
cell rate averages to the SCR again. At this time, more cells (up to the MBS) can be sent
at the PCR again.
CBR (Constant Bit Rate)
– is for connections that support constant rates of data
transfer. The only parameter you need to worry about in CBR is PCR.
UBR (Unspecified Data Rate)
– is for connections that have variable traffic. The only
parameter you need to worry about in UBR is PCR.
rtVBR (real time Variable Bit Rate)
– is for connections that, while having variable
traffic, require precise timing between traffic source and destination. PCR, SCR and MBS
must all be set for rtVBR.
nrtVBR (non real time Variable Bit Rate)
– is for connections that have variable traffic,
do not require precise timing, but still require a set bandwidth availability. PCR, SCR and
MBS must all be set for nrtVBR.
Summary of Contents for Cerberus P 6331-4A
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