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ForeRunner ATM Switch Network Configuration Manual
Configuring PVCs
The specific combinations of these parameters that make up the ATM Forum contracts are
defined as follows:
1. cbr <pcr01>
2. cbr0 <pcr0> <pcr01> [tag]
3. vbr <pcr01> <scr01> <mbs01>
4. vbr0 <pcr01> <scr0> <mbs0> [tag]
5. abr <pcr01> <mcr>
The
cbr <pcr01>
contract is for CBR traffic. It only uses the first leaky bucket to assess the
conformance to PCR of the aggregate of the CLP=0 cells and the CLP=1 cells. Cells which fail
the PCR CLP=0+1 test are discarded.
The
cbr0 <pcr0> <pcr01> [tag]
contract is for CBR traffic. It uses the first leaky bucket to
assess the conformance to PCR of the CLP=0 cells. It uses the second leaky bucket to assess the
conformance to PCR of the aggregate of the CLP=0 and the CLP=1 cells. If the
tag
option is
set, the cells which fail the PCR CLP=0 test are tagged as CLP=1 and passed on to the second
leaky bucket to be tested for PCR CLP=0+1 conformance. Cells which fail the PCR test on
CLP=0+1 are discarded. If the
tag
option is not set, cells which fail the PCR CLP=0 test are
discarded and cells which fail the PCR test on CLP=0+1 are discarded.
The
vbr <pcr01> <scr01> <mbs01>
contract is for VBR traffic. The first leaky bucket
assesses the conformance to PCR of the aggregate of CLP=0 cells and the CLP=1 cells and the
second leaky bucket assesses the conformance to SCR and BT of this same combination. Cells
which fail the PCR test are dropped. Cells which pass the PCR test, but which fail SCR and BT
test are dropped.
The
vbr0 <pcr01> <scr0> <mbs0> [tag]
contract is for VBR traffic. It uses the first leaky
bucket to assess the conformance to PCR of the aggregate of the CLP=0 and the CLP=1 cells.
Cells that fail this test are discarded. It uses the second leaky bucket to assess the conformance
to SCR and BT of the CLP=0 cells. If the
tag
option is set, the cells which fail the SCR and BT
CLP=0 test are tagged as non-conforming cells. If the
tag
option is not set, cells which fail the
SCR and BT CLP=0 test are discarded.
The
abr <pcr01> <mcr>
contract is for ABR traffic. It only uses the first leaky bucket to
assess the conformance to PCR of the aggregate of the CLP=0 cells and the CLP=1 cells. Cells
which fail the PCR CLP=0+1 test are discarded. The MCR is the guaranteed minimum rate
and the PCR is the maximum required rate. The MCR may be set to 0, which indicates “best
effort” service. If MCR is set greater than 0, then the rate is guaranteed, up to MCR. However,
between MCR and PCR, cells may be dropped when congestion is experienced.