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WIRELESS ROUTER ADSL
5.1.1 ATM VC & QoS
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 traffi c line’s priority. Virtual Circuit:
Select the VC number you want to setup. VPI: Virtual Path Identifi er. The valid range for the VPI is 0 to 255. VCI: Virtual
Channel Identifi er. The valid range for the VCI is 1 to 65635 (0 to 31 is reserved for local management of ATM traffi c).
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 (Unspecifi ed Bit Rate). These QoS types are all controlled by the parameters specifi ed
below, including PCR, SCR, and MBS. PCR: 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 depen-
dent on the line speed. SCR: Sustained Cell Rate (SCR) is the mean cell rate of a bursty, on-off traffi c source that can be
sent at the peak rate, and a parameter for burst-type traffi c. SCR may not be greater than the PCR; the system default is
0 cells/sec. MBS: 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 thistime, more cells (up to
the MBS) can be sent at the PCR again. CBR is for connections that support constant rates of data transfer. The only
parameter you need to worry about in CBR is PCR. UBR is for connections that have variable traffi c. The only param-
eter you need to worry about in UBR is PCR.rtVBR is for connections that, while having variable traffi c, require precise
timing between traffi csource and destination. PCR, SCR and MBS must all be set for rtVBR. nrtVBR is for connections
that have variable traffi c, do not require precise timing, but still require a set bandwidth availability. PCR, SCR and MBS
must all be set for nrtVBR.
5.1.2 Encapsulation
Select the encapsulation protocol your ISP uses. The following section will vary depending on which encapsulation
protocol you select.