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

ATM Connection Configuration

UBR Connections

The unspecified bit rate (UBR) connection service is similar to the ABR connection service for bursty data. However, UBR traffic is delivered only when there is spare bandwidth in the network. This is enforced by setting the CLP bit on UBR traffic when it enters a port.

Therefore, traffic is served out to the network only when no other traffic is waiting to be served first. The UBR traffic does not affect the trunk loading calculations performed by the switch software.

The parameters for a UBR connection are shown in Figure 7-10in the sequence in which they occur during the execution of the addcon command.

The UBR policing definitions are summarized in Table 7-7.

Figure 7-10 UBR Connection Prompt Sequence

UBR

PCR(0+1)

%Util (default to 1%) CDVT(0+1)

FBTC (AAL5 Frame based traffic control, enable/disable) CLP Setting (yes, no) (same as CLP tagging)

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

10228

Table 7-7	UBR 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)
UBR	UBR.1	CLP(0+1)	no	off	n/a
	when CLP setting =
	no
UBR	UBR.2	CLP(0+1)	no	CLP(0)	yes
	when CLP setting =
	yes

7-22Cisco BPX 8600 Series Reference