Cisco Systems 8600 Series manual VBR Connection, UPC Overview

Traffic Policing Examples

Figure 7-14 VBR Connection, UPC Overview

VBR Traffic

		Verify	To UPC for each
	Multiple PVCs		individual PVC
		VPIs,		Policing
CPE		VCIs

Cells		PCR
per	MBS=
sec.		SCR
	PCR x BT
	Time

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.

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

Example: VBR.2 Policing = 2

5 4 3 CLP=1 CLP=0 CLP=1

21

CLP=0 CLP=0

5

3

CLP(1) cells compliant with Leaky Bkt 1, admit to network

CLP=1

CLP=1

Time

4

2

1

4

2

1

interval

CLP=0

CLP=0

CLP=0

CLP=0

CLP=0

CLP=0

variations

CLP(0) cells

Admit to network

+

CDVT(0+1)

compliant with

+

Leaky Bkt 1

Leaky Bkt 1

BT+ CDVT

are applied to

Leaky Bkt 2

PCR(0+1)

Leaky Bkt 2

S6344

with Policing = 2.

SCR

ATM Connections 7-27