Juniper ACX2000 Configuration Guide

On ACX Series routers, policing is cell based and configured in the ingress path of the
ATM IMA pseudowire interface at the [edit firewall] hierarchy level. The following ATM
policing features are supported:
•
ATM Adaption Layer 5 (AAL5) pseudowires on which cell-based policing is performed
before packet assembly.
•
Per-ATM IMA channel policing.
•
Traffic classes—Constant bit rate (cbr), real-time variable bit rate (rtvbr), non-real-time
variable bit rate (nrtvbr), and unspecified bit rate (ubr). All traffic classes must include
the peak-rate and cdvt statements for the configuration to work. With the peak-rate
statement, you can limit the maximum traffic allowed by specifying the largest number
of cells per second that the policer processes before it drops packets. The cdvt
statement ensures that the configuration functions correctly.
•
For nonconforming cells, the discard, discard-tag, and count actions at the [edit firewall
atm-policer policer-name] hierarchy level. The discard-tag action is applicable to variable
bit-rate—nrtvbr and rtvbr—traffic classes.
Cell-Based ATM Shaping
Cell-based ATM shaping uses cell-based queuing and scheduling to determine the
maximum amount of traffic that can be transmitted on an ATM IMA pseudowire.
Packet-based shaping is not supported. On ACX Series routers, ATM shaping is configured
in the egress path of the ATM IMA pseudowire interface at the [edit class-of-service]
hierarchy level. The following ATM shaping features are supported:
•
Prioritized bit rate—Constant bit rate (cbr) is the highest priority, followed by variable
bit rate—nrtvbr and rtvbr. Unspecified bit rate (ubr) is similar to the best-effort service
for Ethernet traffic.
•
Constant bit rate shaping—Constant bit rate (cbr) shaping uses the peak cell rate to
limit the number of cells per second that the shaper processes before it drops packets.
•
Variable bit rate shaping—Variable bit rate shaping (nrtvbr and rtvbr) uses peak-rate
and sustained-rate.
•
Unspecified bit rate—Unspecified bit rate (ubr) uses peak-rate with the lowest transmit
priority.
The default shaping parameter is unspecified bit rate, which is similar to the best-effort
service for Ethernet traffic.
Fixed Classification
Fixed classifiers map all traffic on an interface to the forwarding class and loss priority.
The forwarding class determines the output queue. A scheduler uses the loss priority to
control packet discard during periods of congestion by associating different drop profiles
with different loss priorities. On ACX Series routers, the fixed classifier is associated with
the ingress interface. Packets are assigned on the basis of the type of fixed classification
associated with the logical interface. To configure a fixed classifier, include the
Copyright © 2017, Juniper Networks, Inc.896
ACX Series Universal Access Router Configuration Guide

Juniper ACX2000 Specifications

General

Brand	Juniper
Model	ACX2000
Category	Network Router
Language	English