Queuing Modes - Cisco 10000 Series Configuration Manual

Bandwidth Distribution Between Queues

Queuing Modes

The Cisco 10000 series router supports the following queuing modes:
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atm pxf queuing Mode
The atm pxf queuing mode supports low VC counts. Before you configure VCs on an interface, configure
the queuing mode for the port (atm pxf queuing or no atm pxf queuing). After you configure the mode,
then configure the VCs. Do not change the mode while VCs are configured on the interface. If you need
to change the mode, delete the VCs first and then change the mode. Changing the mode while VCs are
configured can produce undesired results.
To support a low VC count, configure the atm pxf queuing command on each port of the Cisco 10000
series router. For Cisco IOS Release 12.3(7)XI2 and later releases, all line cards support a maximum of
28,672 VCs when configured for hierarchical shaping.
For releases prior to Cisco IOS Release 12.3(7)XI2, the OC-3 and OC-12 line cards support a maximum
Note
of 14,336 VCs when configured for hierarchical shaping. The DS3/E3 line card supports a maximum of
8,192 VCs when configured for shaping. You can configure the maximum number of VCs across the
ports in any fashion, provided that you do not exceed the per-port maximum. The OC-3 line card is
limited to 8,192 VCs per port and the DS3 is limited to 4,096 VCs per port.
The Cisco 10000 series router supports the following ATM traffic classes when you configure the atm
pxf queuing command:
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If you use the ubr+ command to configure shaped UBR, the router accepts the PCR value you specify,
Note
but it does not use it. The router does not notify you of this behavior.
Cisco 10000 Series Router Quality of Service Configuration Guide
5-8
atm pxf queuing Mode, page 5-8
no atm pxf queuing Mode, page 5-9
Shaped and unshaped unspecified bit rate (UBR)
To configure shaped UBR, enter the ubr command and specify the PCR value. For unshaped UBR,
do not specify the PCR value.
Variable bit rate-nonreal time (VBR-nrt)
To configure VBR-nrt QoS, use the vbr-nrt command and specify the output PCR, output
sustainable cell rate (SCR), and output maximum burst cell size (MBS).
Constant bit rate (CBR)
To configure CBR QoS, use the cbr command and specify the average cell rate for the ATM circuit
emulation service (CES) for an ATM permanent virtual circuit (PVC).
Chapter 5 Distributing Bandwidth Between Queues
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