Cisco Systems 8600 Series CBR Connections, CBR Policing Definitions ATM Forum TM Spec PCR Flow

ATM Connection Configuration

CBR Connections

The CBR (constant bit rate) category is a fixed bandwidth class. CBR traffic is more time dependent, less tolerant of delay, and generally more deterministic in bandwidth requirements. CBR is used by connections that require a specific amount of bandwidth to be available continuously throughout the duration of a connection. Voice, circuit emulation, and high-resolution video are typical examples of traffic utilizing this type of connection. A CBR connection is allowed to transmit cells at the peak rate, below the peak rate, or not at all. CBR is characterized by peak cell rate (PCR).

The parameters for a CBR connection are shown in Figure 7-3in the sequence in which they occur during the execution of the addcon command. The CBR policing definitions are summarized in Table 7-5.

Figure 7-3 CBR Connection Prompt Sequence

CBR

PCR(0+1)

%Util

CDVT(0+1)

1

Policing (4 or 5)

Trunk cell routing restrict (Y/N) [Y]

1For policing prompt:

4 = PCR policing only

5 = policing off

Note: BW allocation = (PCR)x(%Util)

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Table 7-5	CBR Policing Definitions
	ATM Forum TM
	spec. 4.0	PCR Flow	CLP	SCR Flow	CLP
	conformance	(1st leaky	tagging (for	(2nd leaky	tagging (for
Connection Type definition		bucket)	PCR flow)	bucket)	SCR flow)
CBR	CBR.1	CLP(0+1)	no	off	n/a
	when policing set to
	4 (PCR Policing
	only)
CBR	When policing set	off	n/a	off	n/a
	to 5 (off)

ATM Connections 7-13