Cabletron Systems SmartCell ZX-250, User Manual

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SmartCell ZX-250 User Guide 4-15
Switch Administration PVC Connections
Use the
show vccmask
command to view the four preconfigured VPI/VCI combinations.
SmartCell ZX # show vccmask
MaskIndex VpiShift VciShift
(In bits) (In bits)
============================================================================
0 0 12
1 2 10
2 4 8
3 6 6
SmartCell ZX #
VCCMask combinations dictate what numerical values can be used for VPI/VCI pairs. Any VPI and VCI pairs that fit
the bit distribution of one of the indexed combinations can be used for defining a PVC. If the VPI and VCI values do
not fit one of the indexed combinations, the SmartCell ZX-250 uses the closest matching indexed combination.
If you need to use values for VPI and VCI that do not fall within the range of one of the preconfigured indexed
combinations, use the
set vccmask
command to replace one of the preconfigured combinations.
For example, change VCCMask indexed combination zero (0) from VPI = 0 bits and VCI = 12 bits to
VPI = 3 bits and VCI = 9 bits.
s•
Use
set vccmask
to change the VPI/VCI values to 3/9.
SmartCell ZX # set vccmask
MaskIndex(0) :
<we replace the first VPI/VCI pair
VPIShift(0) : 3
VCIShift(12) : 9
SmartCell ZX #
¢•
Use the
show vccmask
command to see the new VPI/VCI combination.
SmartCell ZX # show vccmask
MaskIndex VpiShift VciShift
(In bits) (In bits)
============================================================================
0 3 9 <for index 0, VPI/VCI now equals 3/9
1 2 10
2 4 8
3 6 6
SmartCell ZX #
Table 4-1 Values for VPI and VCI
VCC Mask Index VPI Bits VPI Values VCI Bits VCI Values
0 0 0 12 0 to 4096
1 2 0 to 3 10 0 to 1023
2 4 0 to 15 8 0 to 255
3 6 0 to 63 6 0 to 63