Traffic - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - QUALITY OF SERVICE CONFIGURATION GUIDE 2010-09-22 Configuration Manual

Configuring a Parameter Definition to Adjust Frame Shaping Rates for VDSL Traffic
Copyright © 2010, Juniper Networks, Inc.
Chapter 29: Configuring Byte Adjustment for Shaping Rates with QoS Parameters
traffic-class
vlan id
Packet fragmentation can occur at a DSLAM because of the associated segment header
that is added for VDSL2 in frame shaping mode. Because the segment header is not
included in the ANCP rate report, the forwarding rate on an E Series router can be higher
than the DSLAM rate, which can result in packet loss.
You can use a QoS parameter expression with the frame byte-adjustment application
to reduce the forwarding rate so that it matches the VDSL downstream rate at the DSLAM.
You can also configure the cell mode application to account for ADSL downstream traffic
that is also being received.
To configure a QoS parameter definition to adjust frame shaping rates and manage
packet fragmentation:
Configure the QoS parameter definition to accept downstream shaping rate
1.
instantiation from ANCP.
host1(config)#qos-parameter-define ancp-downstream application
qos-downstream-rate
Configure the QoS parameter definition for the frame byte-adjustment application
2.
to adjust the packet header.
host1(config)#qos-parameter-define frame-byte application
qos-frame-byte-adjustment
You can also configure the qos-byte-adjustment application with a different value.
Create the QoS parameter definition for the cell mode application to track the
3.
subscriber DSL type.
host1(config)#qos-parameter-define sp-qos-cell-mode application qos-cell-mode
The ADSL type corresponds to cell mode and VDSL corresponds to frame mode.
Configure the parameter expression to reduce the shaping rate to account for packet
4.
fragmentation.
In the following expression, the adjustment is applied to traffic with frame shaping
mode only. The byte adjustment value is 8 and the shaping rate is reduced by 2 percent.
host1(config)#scheduler-profile service-provider-business
host1(config-scheduler-profile)# shaping-rate ancp-downstream - (ancp-downstream
% 2 * (1 - sp-qos-cell-mode))
TIP: To determine the expression value and the byte adjustment required,
you must account for the actual segmentation header overhead added
by the DSLAM. DSLAMs have different segmentation header overheads.
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