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Configuring ATM IMA

 

The following sections explain how to create an ATM IMA group and to configure it according to your requirements:

Creating an IMA Group (ATM Interfaces)

To create an IMA group, perform the following steps:

  1. In configuration mode, go to the [edit chassis] hierarchy level:
  2. Configure the Flexible Port Concentrator (FPC) slot and the Physical Interface Card (PIC) slot as needed.
  3. Configure the device count. The device count can be set starting from 1 through 42 in the aggregated device options for inverse multiplexing for ATM at the [edit chassis fpc fpc-slot pic pic-slot] hierarchy level.

This results in the creation of interfaces from at-x/y/g through at-x/y/g+count–1, where the variable count is the number of interfaces and the variable g is chosen such that there is no conflict with non-IMA at-x/y/z interfaces on the same PIC.

The PIC is automatically rebooted when a configuration that changes the IMA group count is committed.

Configuring Group ID for an IMA Link on a T1 Interface or an E1 Interface

A group ID is assigned to all links in an IMA group.

To assign a group ID to a T1 or an E1 interface:

  1. In configuration mode, go to the [edit interfaces interface-name] hierarchy level, where the interface name is t1-fpc/pic/port:m:n, e1-fpc/pic/port:n, or t1|e1-fpc/pic/port.
  2. Configure the encapsulation as ima.
  3. Configure the IMA group ID from 16 through 57. Note that this group ID is the same for all T1/E1 interfaces for a particular ATM IMA interface.

Implement the aforementioned procedure to apply a group ID for all applicable T1 or E1 interfaces.

Configuring ATM Encapsulation Options

To configure the logical link-layer encapsulation for an ATM interface to support IMA:

  1. In configuration mode, go to the [edit interfaces interface-name] hierarchy level, where the interface name is at-fpc/pic/port.
  2. Configure the logical interface (unit) as 0 and set the encapsulation for this logical interface as either ATM cell relay for CCC or ATM VC for CCC.

Configuring IMA Group Options

To configure the various options for an IMA group on an ATM interface:

  1. In configuration mode, go to the [edit interfaces interface-name ima-group-options] hierarchy level, where the interface name is at-fpc/pic/port.
  2. Configure the maximum differential delay between the links in the IMA group. You can configure the maximum differential delay from 1 millisecond through 56 milliseconds. By default, 25 milliseconds is set.
  3. Configure the frame length of the ICP cell as 32, 64, 128, or 256. By default, 128 is set.
  4. Configure the IMA group frame synchronization state parameters alpha, beta, and gamma.

    For the default values and parameter range for alpha, beta, and gamma, see ATM IMA Configuration Overview.

  5. Configure IMA group minimum active links.
  6. Configure the symmetry of the IMA group as either symmetrical configuration and operation or symmetrical configuration and asymmetrical operation.

    For information about symmetry, see ATM IMA Configuration Overview.

  7. Configure a test procedure to start and end the test pattern procedure.

    For information about test procedure, see ATM IMA Configuration Overview.

  8. Configure a transmit clock to reflect the primary reference source (PRS) of the clock for each link in a group either in common timing mode or independent timing mode. By default, common timing mode is selected.
  9. Configure the IMA specification version as either version 1.0 or version 1.1. By default, IMA version 1.1 is selected.