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Defining the ATM Traffic-Shaping Profile
When you use an ATM encapsulation on ATM1 and ATM2
IQ interfaces, you can define bandwidth utilization, which consists
of either a constant rate or a peak cell rate, with sustained cell
rate and burst tolerance.
These values are used in the ATM generic cell-rate
algorithm, which is a leaky bucket algorithm that defines the short-term
burst rate for ATM cells, the maximum number of cells that can be
included in a burst, and the long-term sustained ATM cell traffic
rate.
If your routing platform is equipped with an ATM2
IQ PIC, each VC can have independent shaping parameters. For more
information, see Defining Virtual Path Tunnels.
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Note:
When the DS3 or E3 port parameters are not identical on all
ports of a multiport ATM DS3 or E3 PIC, the ATM PIC driver might not
always use the minimum port shaping rate (of all the ports on a multiport
ATM DS3 or E3 PIC) selected for cell transmission shaping. The PIC's
shaping rate is always updated to conform to the last port setting
updated by the PIC software driver, rather than use the minimum port
(shaping) rate. There is no syslog message to inform the user of the
shaping rate decision applied by the software driver.
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By default, the bandwidth utilization is unlimited;
that is, unspecified bit rate (UBR) is used. Also, by default, buffer
usage by VCs is unregulated.
To define limits to bandwidth utilization, include
the shaping statement:
-
shaping {
- (cbr rate | rtvbr peak rate sustained rate burst length | vbr peak rate sustained rate burst length);
-
queue-length number;
- }
For a list of hierarchy levels at which you can
include this statement, see shaping.
The rtvbr statement is supported on ATM2
IQ PICs only. The queue-length statement is supported on
ATM1 PICs only.
To configure VP tunnels on ATM2 IQ interfaces,
include the shaping statement at the [edit interfaces interface-name atm-options vpi vpi-identifier] hierarchy level:
- [edit interfaces interface-name atm-options
vpi vpi-identifier]
-
shaping {
- (cbr rate | rtvbr peak rate sustained rate burst length | vbr peak rate sustained rate burst length);
- }
When configuring ATM traffic shaping, you can do
the following:
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