Cisco BPX 8650, Installation And Configuration Manual

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Cisco BPX 8600 Series Installation and Configuration
Release 9.3.30, Part Number 78-12907-01 Rev. E0, May 2005
Chapter 21 Configuring ATM Connections
Traffic Policing Examples
Figure 21-21 VBR Connection, UPC Overview
Leaky Bucket 1
Leaky bucket 1 polices for the PCR compliance of all cells seeking admission to the network, both those
with CLP = 0 and those with CLP =1.
For example, cells seeking admission to the network with CLP set equal to 1 may have either
encountered congestion along the user’s network or may have lower importance to the user and have
been designated as eligible for discard in the case congestion is encountered. If the bucket depth in the
first bucket exceeds CDVT (0+1), it discards all cells seeking admission. It does not tag cells.
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