Chapter 10 Quality of Service (QoS)
VMG1312-B10A User’s Guide
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DSCP is backward compatible with the three precedence bits in the ToS octet so that non-DiffServ
compliant, ToS-enabled network device will not conflict with the DSCP mapping.
The DSCP value determines the forwarding behavior, the PHB (Per-Hop Behavior), that each packet
gets across the DiffServ network. Based on the marking rule, different kinds of traffic can be
marked for different kinds of forwarding. Resources can then be allocated according to the DSCP
values and the configured policies.
IP Precedence
Similar to IEEE 802.1p prioritization at layer-2, you can use IP precedence to prioritize packets in a
layer-3 network. IP precedence uses three bits of the eight-bit ToS (Type of Service) field in the IP
header. There are eight classes of services (ranging from zero to seven) in IP precedence. Zero is
the lowest priority level and seven is the highest.
Automatic Priority Queue Assignment
If you enable QoS on the Device, the Device can automatically base on the IEEE 802.1p priority
level, IP precedence and/or packet length to assign priority to traffic which does not match a class.
The following table shows you the internal layer-2 and layer-3 QoS mapping on the Device. On the
Device, traffic assigned to higher priority queues gets through faster while traffic in lower index
queues is dropped if the network is congested.
DSCP (6 bits)
Unused (2 bits)
Table 50
Internal Layer2 and Layer3 QoS Mapping
PRIORITY
QUEUE
LAYER 2
LAYER 3
IEEE 802.1P USER
PRIORITY
(ETHERNET
PRIORITY)
TOS (IP
PRECEDENCE)
DSCP
IP PACKET
LENGTH (BYTE)
0
1
0
000000
1
2
2
0
0
000000
>1100
3
3
1
001110
001100
001010
001000
250~1100
4
4
2
010110
010100
010010
010000
5
5
3
011110
011100
011010
011000
<250
Summary of Contents for VWG1312-B10A
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Page 8: ...Contents Overview VMG1312 B10A User s Guide 8 Troubleshooting 291 ...
Page 18: ...Table of Contents VMG1312 B10A User s Guide 18 ...
Page 19: ...19 PART I User s Guide ...
Page 20: ...20 ...
Page 34: ...Chapter 2 The Web Configurator VMG1312 B10A User s Guide 34 ...
Page 39: ...Chapter 4 Tutorials VMG1312 B10A User s Guide 39 7 Click Apply to save your settings ...
Page 79: ...79 PART II Technical Reference ...
Page 80: ...80 ...
Page 168: ...Chapter 9 Routing VMG1312 B10A User s Guide 168 ...
Page 186: ...Chapter 10 Quality of Service QoS VMG1312 B10A User s Guide 186 ...
Page 212: ...Chapter 13 Interface Group VMG1312 B10A User s Guide 212 ...
Page 228: ...Chapter 15 Firewall VMG1312 B10A User s Guide 228 ...
Page 234: ...Chapter 17 Parental Control VMG1312 B10A User s Guide 234 ...
Page 244: ...Chapter 19 Certificates VMG1312 B10A User s Guide 244 ...
Page 248: ...Chapter 20 Log VMG1312 B10A User s Guide 248 ...
Page 252: ...Chapter 21 Traffic Status VMG1312 B10A User s Guide 252 ...
Page 258: ...Chapter 24 IGMP Status VMG1312 B10A User s Guide 258 ...
Page 262: ...Chapter 25 xDSL Statistics VMG1312 B10A User s Guide 262 ...
Page 264: ...Chapter 26 User Account VMG1312 B10A User s Guide 264 ...
Page 270: ...Chapter 29 TR 064 VMG1312 B10A User s Guide 270 ...
Page 274: ...Chapter 30 Time Settings VMG1312 B10A User s Guide 274 ...
Page 280: ...Chapter 32 Logs Setting VMG1312 B10A User s Guide 280 ...
Page 298: ...Chapter 36 Troubleshooting VMG1312 B10A User s Guide 298 ...
Page 338: ...Appendix C Pop up Windows JavaScripts and Java Permissions VMG1312 B10A User s Guide 338 ...
Page 352: ...Appendix D Wireless LANs VMG1312 B10A User s Guide 352 ...
Page 368: ...Appendix G Legal Information VMG1312 B10A User s Guide 368 ...
Page 376: ...VMG1312 B10A User s Guide 376 Index ...