Cabletron Systems SmartCell 6A000 - Manual (Page 50)

4-16 SmartCell 6A000 User Guide
Setting Up PVC Connections Switch Administration
3. Use add pvc to successively create point-to-multipoint PVCs for ports B2, B3, and C1.
SmartCell ZX # add pvc
ConnType(PTP) : pmp
LowPort(A1) :
LowVPI(0) :
LowVCI(33) : 100
HighPort(A1) : b2
HighVPI(0) :
HighVCI(34) : 100
FwdTrafficDescriptorIndex(1) :
BkwTrafficDescriptorIndex(1) : 4
SmartCell ZX #
Perform step 3 for ports B3 and C1.
4. Connect the workstations to their respective ports.
5. Configure the workstations with the same subnet and VPI/VCI pair.
The broadcasting workstation on port A1 can send traffic to the receiving workstations on ports B2, B3, and C1.
4.5.3 Non-zero VPIs
The SmartCell 6A000 uses 12 bits to define VPI/VCI pairs. vccmask determines how many of the 12 bits are used for
the VPI and how many are used for the VCI. vccmask uses a 2-bit register to hold four different VPI/VCI 12-bit
combinations. Table 4-1 shows the registers and the values that come preconfigured on the SmartCell 6A000.
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 6A000 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.
Table 4-1 Values for VPI and VCI
VCC Index VPI Bits VPI Values VCI Bits VCI Values
0 0 0 12 0 to 4095
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