Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?


Configuring Shaping on an ATM IMA Pseudowire


On ACX Series routers, ATM shaping is applied in the egress direction only. Only cell-based shaping is supported. A traffic control profile, which defines the ATM scheduling parameters, is configured at the [edit class-of-service] hierarchy level. The traffic control profile is then applied to the ATM logical interface configured at the [edit class-of-service] hierarchy level.


The configuration of ATM shaping requires the inclusion of the per-unit scheduler statement at the [edit interfaces interface-name] hierarchy level.


Configuring shaping on an ATM IMA pseudowire is not applicable on ACX5048 and ACX5096 routers.

The following steps require you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the CLI User Guide.

To configure a traffic-shaping profile on an ATM IMA pseudowire:

  1. Define the ATM IMA pseudowire. For information about defining the ATM IMA pseudowire, see Configuring Inverse Multiplexing for ATM (IMA) on ACX Series.
  2. In configuration mode, go to the [edit class-of-service] hierarchy level:
  3. Specify the traffic-shaping profile:

    The following steps describe the traffic control profile options that you can configure. The options include atm-service, delay-buffer-rate, max-burst-size, peak-rate, and sustained-rate.

  4. (Optional) Specify the service category that determines the traffic-shaping parameter for the ATM queue at the ATM IMA pseudowire:

    Select one of the following service traffic categories, depending on the needs of your network: constant bit rate (cbr), non-real-time variable bit rate (nrtvbr), or real-time variable bit rate (rtvbr). All service traffic categories must include the peak-rate and cdvt statements for the configuration to work. The peak-rate statement limits the maximum traffic allowed and the cdvt statement ensures that the configuration functions correctly.

  5. (Optional) Specify the delay-buffer calculation:

    The delay-buffer calculation can be specified as cells per second—1000 cells per second (cps) through 160,000,000,000 cps.

  6. (Optional) Define the maximum number of cells that a burst of traffic can contain, from 1 through 4000 cells:
  7. Define the largest number of cells per second that the shaper processes before it drops packets, from 61 cps through 38,641 cps:

    The maximum peak rate value depends on the number of links in the IMA bundle—the more the number of links, the higher the possible peak rate.

  8. (Optional) Define the normal traffic rate averaged over time, from 61 cps through 38,641 cps:
  9. To complete the configuration, configure the per-unit scheduler:

After you have configured shaping on the ATM IMA interface, enter the commit command from configuration mode.