Cisco BPX 8650, Руководство по установке и настройке

Страница: 361 / 606

21-49
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 21-25 shows a VBR.2 connection policing example, with policing set to 2, and leaky bucket 2
noncompliant. Leaky bucket 2 is shown policing the CLP(0) cell stream for conformance with maximum
burst size MBS (as specified by BT), and for compliance with SCR (sustained cell rate).
In this example (policing set to 2), CLP tagging is not enabled, so that the cells that have exceeded the
BT + CDVT limit are discarded. In the example, either the sustained cell rate could have been exceeded
for an excessive interval, or a data burst could have exceeded the maximum allowed burst size.
Figure 21-25 VBR.2 Connection, Leaky Bucket 2 Discarding CLP (0) Cells
Figure 21-26 shows a VBR.1 connection policing example, with policing set to 1, and both buckets
compliant.
Leaky bucket 1 is policing the CLP (0+1) cell stream for conformance with the PCR limit.
Leaky bucket 2 is policing the CLP (0+1) cell stream for conformance with CDVT plus maximum burst
size MBS (as specified by BT), and for compliance with SCR sustained cell rate.
+
SCR
BT + CDVT
Leaky Bkt 2
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
CLP(1) cells compliant with Leaky bkt 1, admit to network
CLP(0) cells
compliant with
Leaky Bkt 1,
applied to
Leaky Bkt 2
Connection setup
and compliance status:
VBR.2
Policing = 2
Bkt 1 depth < CDVT(0+1)
Bkt 2 depth > BT + CDVT
S6348
CLP=0
2
CLP=
0
1
To network
CLP=0
4
Two CLP(0) cells, 1 and 2, are shown as
non-compliant with the BT + CDVT limit
of Leaky Bkt 2 and are discarded in this
example where policing = 2. With
policing = 3, they would be tagged as
CLP=1 and admitted to the network.
Discard
Leaky Bkt 1
discards if depth
> CDVT(0+1)