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ATM Connections 7-27
Traffic Policing Examples
Figure 7-14 VBR Connection, UPC Overview
S6344
Admit to network
+
SCR
BT + CDVT
Leaky Bkt 2
For VBR connections, the first bucket
polices PCR compliance within the
CDVT(0+1) limits. The second bucket
polices compliance in terms of
sustained cell rate and data bursts
within the BT + CDVT limits.
VBR Traffic
CPE
Multiple PVCs
To UPC for each
individual PVC
PCR
Clumping
(Cells arriving early, i.e, at a
higher than contracted rate)
Cells arriving late
(at a less than
contracted
cell rate)
TAT TAT TAT TAT TAT TAT TAT TAT
Verify
VPIs,
VCIs
Policing
CLP=1
5
CLP=0
4
CLP=1
3
CLP=0
2
CLP=0
1
+
PCR(0+1)
CDVT(0+1)
Time
interval
variations
Leaky Bkt 1
CLP=1
5
CLP=1
3
CLP=0
4
CLP=0
2
CLP=0
1
Example: VBR.2
Policing = 2
CLP=0
4
CLP=0
2
CLP=0
1
CLP(1) cells compliant with Leaky Bkt 1, admit to network
CLP(0) cells
compliant with
Leaky Bkt 1
are applied to
Leaky Bkt 2
with Policing = 2.
Time
Cells
per
sec.
SCR
MBS=
PCR x BT