Juniper ACX2000 Configuration Guide

IMA Version
Either IMA 1.0 (af-phy-0086.000-IMA) or IMA 1.1 (af-phy-0086.001-IMA) can be selected
through the CLI. To choose the IMA specification version, execute the set interfaces
interface-name ima-group-options (1.0|1.1) configuration command. Note that, if you do
not specify the version, IMA 1.1 is selected by default.
NOTE: IMA 1.0 and IMA 1.1 do not interoperate.
The IMA v1.1 specification increments the operations and maintenance (OAM) label value
used in the IMA OAM cells in order to differentiate v1.1 from v1.0 IMA units.
IMA Frame Length
An IMA frame consists of ATM cells, an ICP cell, and filler cells (if required). When you
configure an IMA group, you can choose a frame length of 32, 64, 128, or 256. The frame
length can be selected independently in each direction and in each group. To set the
frame length, execute the set interface interface-name frame-length (32 |64 |128 |256)
configuration command. Note that if the frame length is not specified, the frame length
value of 128 is selected by default.
Transmit Clock
When you create an IMA group, you can configure a common transmit clock timing mode
or an independent transmit clock timing mode to reflect the primary reference source
(PRS) of the clock for each link in a group. By default, the common mode is selected. To
select the transmit clock timing mode, execute the set interface interface-name
ima-group-options transmit-clock (common | independent) configuration command.
IMA Group Symmetry
You can configure an IMA group to allow symmetric or asymmetric cell rate transfer over
an IMA virtual link. You can configure the IMA group with one of the following modes:
•
Symmetrical configuration and operation—In this mode, on the ATM IMA device, an
IMA link must be configured in each direction for all physical links that the ATM IMA
device is configured to use. In this mode, the ATM IMA device can transmit and receive
ATM layer cells over the physical links on which the IMA links running in both directions
are Active.
•
Symmetrical configuration and asymmetrical operation—In this mode, on the ATM
IMA device, an IMA link must be configured in each direction for all physical links that
the ATM IMA device is configured to use. In this mode, the ATM IMA device can transmit
ATM layer cells over the physical links on which the IMA links in the transmit direction
are Active, while the IMA links in the receive direction are not Active or contrariwise.
Asymmetrical configuration and operation are not supported.
The mode can be configured through the CLI when an IMA group is created. To select
the symmetry option, execute the set interface interface-name ima-group-options symmetry
175Copyright © 2017, Juniper Networks, Inc.
Chapter 6: Configuring ATM Interfaces

Juniper ACX2000 Specifications

General

Brand	Juniper
Model	ACX2000
Category	Network Router
Language	English