Table 29: Header Lengths for Ethernet Encapsulation
(continued)
Number of Bytes
Header
34 bytes
Total
Table 30 on page 295 lists the header lengths for the ATM encapsulation, which
represents the B-RAS protocol overhead. The interface stack is PPPoA over ATM 1483
with LLC Mux. The ATM AAL5 trailer is considered cell tax and is not part of the byte
adjustment calculation.
Table 30: Header Lengths for ATM Encapsulation
Number of Bytes
Header
4 bytes
ATM AAL5 LLC
2 bytes (2-protocol id)
PPP
6 bytes
Total
The byte adjustment calculation for these encapsulations is:
Byte Adjustment for Frame Shaping of VDSL Traffic Overview
Packet fragmentation can occur at a DSLAM because of the associated segment
header that is added for VDSL2 in frame 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 rate at the DSLAM. To adjust
rates for interfaces with frame shaping mode, apply the frame byte-adjustment
application (
qos-frame-byte-adjustment
).
When you apply a parameter with the
qos-byte-adjustment
application to an interface
with frame shaping mode, you adjust shaping rates to account for different layer 2
encapsulations only.
System Calculation for Byte Adjustment of ADSL and VDSL Traffic
You can create parameter instances for the cell byte-adjustment application and the
frame byte-adjustment application on the same system. The system performs the
byte adjustment calculation based on the shaping mode specified. The byte adjustment
can have both a positive and negative value.
Table 31 on page 296 lists the final byte adjustment value that the system uses
depending on the configured shaping mode and the value that you configured for
the byte adjustment applications.
Byte Adjustment for ADSL and VDSL Traffic Overview
■
295
Chapter 29: Configuring Byte Adjustment for Shaping Rates with QoS Parameters
Содержание JUNOSE 11.1.X - QUALITY OF SERVICE CONFIGURATION GUIDE 3-21-2010
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Страница 24: ...xxiv List of Figures JUNOSe 11 1 x Quality of Service Configuration Guide...
Страница 28: ...xxviii List of Tables JUNOSe 11 1 x Quality of Service Configuration Guide...
Страница 33: ...Part 1 QoS on the E Series Router Quality of Service Overview on page 3 QoS on the E Series Router 1...
Страница 34: ...2 QoS on the E Series Router JUNOSe 11 1 x Quality of Service Configuration Guide...
Страница 44: ...12 Classifying Queuing and Dropping Traffic JUNOSe 11 1 x Quality of Service Configuration Guide...
Страница 76: ...44 Scheduling and Shaping Traffic JUNOSe 11 1 x Quality of Service Configuration Guide...
Страница 156: ...124 Monitoring QoS Scheduling and Shaping JUNOSe 11 1 x Quality of Service Configuration Guide...
Страница 162: ...130 Scaling Subscribers on the TFA ASIC with QoS JUNOSe 11 1 x Quality of Service Configuration Guide...
Страница 190: ...158 Interface Solutions for QoS JUNOSe 11 1 x Quality of Service Configuration Guide...
Страница 238: ...206 Monitoring QoS Configurations for L2TP JUNOSe 11 1 x Quality of Service Configuration Guide...
Страница 256: ...224 Managing Queuing and Scheduling with QoS Parameters JUNOSe 11 1 x Quality of Service Configuration Guide...
Страница 344: ...312 Monitoring and Troubleshooting QoS JUNOSe 11 1 x Quality of Service Configuration Guide...
Страница 388: ...356 Monitoring QoS Parameter Definitions JUNOSe 11 1 x Quality of Service Configuration Guide...
Страница 391: ...Part 8 Index Index on page 361 Index 359...
Страница 392: ...360 Index JUNOSe 11 1 x Quality of Service Configuration Guide...