Juniper ACX2000 Configuration Guide

Understanding ATM IMA Configuration on ACX Series Router
IMA involves inverse multiplexing and demultiplexing of ATM cells in a round-robin
sequence among links grouped to form a higher-bandwidth logical link whose rate is the
sum of all the link rates. This group of links is called an IMA group. An IMA group can also
be defined as a group of links at the transmitting end that is used to establish an IMA
virtual link to the receiving end. The IMA virtual link is a virtual link that is established
between two IMA units or routers over a number of physical links (in an IMA group). IMA
groups terminate at each end of the IMA virtual link.
You can configure 42 IMA groups. Each group can contain from 1 through 32 links.
You can configure a maximum of 16 IMA groups on the 16-port Channelized E1/T1 Circuit
Emulation MIC (ACX-MIC-16CHE1-T1-CE) and each group can have from 1 through 8 IMA
links. Port numbers starting from 0 through 15 are used for T1/E1 ports; therefore, IMA
port numbers start from 16 onward.
You can configure a maximum of 16 IMA groups on the Channelized OC3/STM1
(Multi-Rate) Circuit Emulation MIC with SFP (ACX-MIC-4COC3-1COC12CE).
To configure an IMA group, execute the set chassis fpc fpc-slot pic pic-slot aggregated
devices ima device-count count configuration command, where count results in the
creation of interfaces from at-x/y/g through at-x/y/g+count-1. The variable g is picked
from 16 onward. For example, if the count variable is set to 4, then the new ATM interfaces
are created from at-x/y/16 through at-x/y/19.
You can implement inverse multiplexing for ATM (IMA) on Juniper Networks ACX Series
routers by configuring an IMA group and its options. The following sections explain the
various options that can be set for an IMA group:
•
IMA Version on page 175
•
IMA Frame Length on page 175
•
Transmit Clock on page 175
•
IMA Group Symmetry on page 175
•
Minimum Active Links on page 176
•
State Transition Variables: Alpha, Beta, and Gamma on page 176
•
IMA Link Addition and Deletion on page 176
•
IMA Test Pattern Procedure on page 177
•
IMA Group Alarms and Group Defects on page 177
•
IMA Link Alarms and Link Defects on page 178
•
IMA Group Statistics on page 179
•
IMA Link Statistics on page 180
•
IMA Clocking on page 181
•
Differential Delay on page 181
Copyright © 2017, Juniper Networks, Inc.174
ACX Series Universal Access Router Configuration Guide

Juniper ACX2000 Specifications

General

Brand	Juniper
Model	ACX2000
Category	Network Router
Language	English