Juniper ACX2000 Configuration Guide

equals 36 is not a power of 2, the lower fill-level is internally adjusted to convert it to
be a number exponentially raised to 2.
•
When fragmentation-map is configured, the forwarding-class carrying the multi-class
0 traffic must be assigned the highest priority and the forwarding-class carrying the
multi-class 3 traffic must be assigned the lowest priority. Such a configuration is
necessary because of the NPU design.
Limitations for CoS on PPP Interfaces
The following restrictions apply for configuring CoS on PPP interfaces on ACX Series
routers:
•
The distribution of excess rate between 2 or more queues that contain the same priority
occurs on a first-come, first-served basis. For example, consider two Queues configured
as follows:
Q1 : Transmit-rate = 10%, Shaping-rate = 20%
Q2 : Transmit-rate = 10%, Shaping-rate = 30% on same priority
The excess rate for Q1 = (20 - 10) = 10%
The excess rate for Q2 = (30 - 10) = 20%
•
The excess rate distribution between Q1 and Q2 does not follow the same ratio but
packets in these queues are served in first-come, first-served manner. The shaping
rate continues to be honored in such a scenario.
Guidelines for Configuring CoS on PPP and MLPPP Interfaces
Keep the following points in mind when you configure CoS on PPP and MLPPP interfaces:
•
You can configure only the any option with the protocol statement at the [edit
class-of-service schedulersscheduler-name drop-profile-map] hierarchy level to specify
the protocol type for the specified scheduler. You cannot specify the TCP or non-TCP
protocol types.
•
CoS functionalities for fractional T1 and E1 interfaces are not supported. CoS is
supported only for full T1 and E1 interfaces.
•
Weighted fair queuing (WFQ) shaping and scheduling model is not supported. Instead
of WFQ, CIR-EIR model is supported to handle shaping and scheduling requirements.
•
Percentage-based rate configuration is not supported for MLPPP LSQ interfaces; only
absolute rate configration in bps is supported.
•
Auto-adjustment of shaping and scheduling rates with the addition or deletion of T1/E1
links is not supported. All the limitations applicable for CoS on ACX routers apply for
PPP interfaces.
•
All the policer limitations on ACX routers for Gigabit Ethernet interfaces are valid for
PPP interfaces. This restriction includes ingress and egress policers. Because these
limitations are chassis-wide, they are also effective for PPP interfaces.
879Copyright © 2017, Juniper Networks, Inc.
Chapter 27: Configuring Class of Service

Juniper ACX2000 Specifications

General

Brand	Juniper
Model	ACX2000
Category	Network Router
Language	English