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B-4
1/19/05
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000
ATM Traffic Descriptors
PCR CLP=0+1
Beta Draft Confidential
PCR CLP=0+1
You can select this option for CBR and unspecified bit rate (UBR) traffic. Traffic
conformance is based only on the PCR of the CLP=0+1 aggregate cell stream with no
best effort. If you select this option, when the cell rate of the aggregate cell stream
exceeds the specified PCR of CLP=0+1, the switch drops all non-conforming cells,
whether they are CLP=0 or CLP=1 cells.
PCR CLP=0+1 With Best Effort
You can select this option only for UBR traffic. A “best effort” attempt is made to
deliver all traffic, but there is no guarantee the switch will not drop cells due to
congestion.
PCR CLP=0+1, SCR CLP=0, and MBS CLP=0
You can select this option only for variable bit rate (VBR) traffic. Traffic conformance
is based on the PCR of the CLP=0+1 aggregate cell stream, as well as the sustainable
cell rate (SCR) and maximum burst size (MBS) of the CLP=0 cell stream with no
Tagging. The cell streams are checked for traffic conformance as follows:
•
The switch checks the cell rate of the CLP=0+1 stream; the switch drops cells
arriving above the PCR. The number of CLP=0 and CLP=1 cells dropped is based
approximately on the ratio of CLP=0 to CLP=1 cells.
For example, if the ratio of CLP=0 to CLP=1 cells is 8 to 5, approximately 8
CLP=0 cells are dropped for every 5 CLP=1 cells that are dropped.
•
The switch checks the SCR and the MBS of the CLP=0 stream. If the cell rate
exceeds the SCR, cells arriving above the SCR are admitted until the stream
exceeds tolerance for such cells. Tolerance is based on the MBS, PCR, and cell
delay variation tolerance (CDVT). The switch drops cells that arrive above the
SCR once the stream exceeds this tolerance level.
Note – For more information about these traffic conformance parameters, see the
ATM UNI Specification, Version 3.1 or Bellcore’s GR-1110-CORE Specification.
Содержание CBX 3500
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