
Configuring ATM Services
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• The rate you desire for each VC
When setting the PCR, keep the following in mind:
• Each VC can have its own PCR.
• The PCR cannot exceed the maximum rate for the physical media. For
example, you cannot exceed 149.76 Mb/s for a SONET/SDH line.
• The PCR specifies the desired rate for the attached physical media (that is,
SONET/SDH, DS-3, or E-3). It does not specify the rate for the ATM network
as a whole. For example, you can specify a full 149.76 Mb/s for each PVC or
control VC on a SONET/SDH connection. However, if the VC ultimately
connects to a lower-speed link (for example, T1 or E1), your PCR is limited to
the maximum rate of that media.
• ATM FRE2 ILI pairs require a minimum PCR value of 300 cells/s. VCs may
fail to operate with PCR values less than 300 cells/s.
• ATM ARE ILI pairs require a minimum PCR value of 128 cells/s. VCs may
fail to operate with PCR values less than 128 cells/s.
• The E-3 framing mode setting affects the maximum PCR setting.
By default, the PCR is set to 2358 cells/s. Table 7-1 lists the valid ranges for each
Bay Networks ATM router.
For additional information about traffic parameters, refer to “ATM Traffic
Parameters” in Chapter 2.
Table 7-1. Valid PCR Ranges
ATM Routers Range (Cells/s)
ATM FRE2 OC-3 SONET/SDH ILI pairs 300 through 365566
ATM ARE OC-3 SONET/SDH ILI pairs 128 through 353207
Model 5780 128 through 353207
ATM ARE DS-3 ILI pairs 128 through 96000
ATM ARE E-3 ILI pairs; G832 Framing Mode 128 through 80000
ATM ARE E-3 ILI pairs; G751 Framing Mode 128 through 72000
Site Manager: Xmit Peak Cell Rate (cells/s): page A-27
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