Configuring Traffic Shaping
Command
Step 6
Router(config-if-atm-vc)# vbr-nrt
output-pcr output-scr output-mbs
Step 7
Router(config-if-atm-vc)# encapsulation
{aal5mux ppp virtual-template number |
aal5ciscoppp virtual-template number |
aal5snap}
Step 8
Router(config-atm-vc)# queue-depth hwm
lwm
Cisco 10000 Series Router Quality of Service Configuration Guide
9-16
Purpose
Enables shaping on the ATM PVC and configures variable bit
rate-nonreal time (VBR-NRT) quality of service (QoS).
output-pcr is the peak cell rate (PCR) for outbound traffic.
output-scr is the sustained cell rate (SCR) for outbound traffic.
(Optional) output-mbs is the output maximum burst cell size, in
number of cells.
Configures the ATM adaptation layer (AAL) and encapsulation
type for an ATM virtual circuit (VC).
aal5mux ppp specifies the AAL and encapsulation type for
multiplex (MUX)-type VCs. The keyword ppp is Internet
Engineering Task Force (IETF)-compliant PPP over ATM. It
specifies the protocol type being used by the MUX encapsulated
VC.
aal5ciscoppp specifies the AAL and encapsulation type for Cisco
PPP over ATM.
aal5snap specifies the AAL and encapsulation type that supports
Inverse ARP. Logical Link Control/Subnetwork Access Protocol
(LLC/SNAP) precedes the protocol datagram.
virtual-template number is the number used to identify the
virtual template.
(Optional) Defines the queue-depth size by setting the high and
low watermarks. This ensures the correct shaping of traffic.
hwm is the high watermark. The value you specify is not required
to be higher than 288.
lwm is the low watermark. The value you specify is not required
to be higher than 256.
For information about the default high and low watermark values,
see the
"High Watermark and Low Watermark Default Values"
section on page
15-25.
The values for high and low watermarks of a VC queue
Note
depend greatly on the queue's configuration, its purpose,
and usage. We recommend that you configure watermark
values small enough so as to avoid exhausting the line
card buffer. When the queues exhaust the buffer, packets
are randomly dropped, which can cause the loss of critical
system traffic.
Chapter 9
Shaping Traffic
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