To adjust the shaping rates to account for different layer 2 encapsulations as well as
the ATM cell pad, header, and trailer on interfaces, apply a parameter with the cell
byte-adjustment application (
qos-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.
Calculation and Example of Byte Adjustment for Cell Shaping
The system counts the bytes transmitted to track the shaping rate. Instead of counting
the actual packet size, the system uses the CPE packet size. You can configure the
byte adjustment so that the shaping rate matches the CPE bandwidth.
By default, the byte adjustment is set to 0. If the overhead between the access node
and CPE is 0, you do not need to configure the byte adjustment value.
Figure 65 on page 294 displays an example of an Ethernet encapsulation and an ATM
encapsulation.
Figure 65: Byte Adjustment Calculation for Ethernet and ATM Encapsulations
Table 29 on page 294 lists the header lengths for the Ethernet encapsulation, which
represents the CPE protocol overhead. The hierarchy is PPPoE over S-VLAN over
Ethernet.
Table 29: Header Lengths for Ethernet Encapsulation
Number of Bytes
Header
14 bytes (6-SA, 6-DA, 2-ethertype)
EnetHeader
8 bytes (2-vmanTci, 2-ethertype,
2-vlanTci, 2-ethertype)
Vstack
6 bytes (1-version/type, 1-code,
2-session id, 2-length)
PppoeHeader
2 bytes (2-protocol id)
Ppp
4 bytes
FCS
294
■
Byte Adjustment for ADSL and VDSL Traffic Overview
JUNOSe 11.1.x Quality of Service Configuration Guide
Содержание JUNOSE 11.1.X - QUALITY OF SERVICE CONFIGURATION GUIDE 3-21-2010
Страница 6: ...vi...
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...