Chapter 10 Quality of Service (QoS)
VMG1312-B10A User’s Guide
184
Token Bucket
The token bucket algorithm uses tokens in a bucket to control when traffic can be transmitted. The
bucket stores tokens, each of which represents one byte. The algorithm allows bursts of up to b
bytes which is also the bucket size, so the bucket can hold up to b tokens. Tokens are generated
and added into the bucket at a constant rate. The following shows how tokens work with packets:
• A packet can be transmitted if the number of tokens in the bucket is equal to or greater than the
size of the packet (in bytes).
• After a packet is transmitted, a number of tokens corresponding to the packet size is removed
from the bucket.
• If there are no tokens in the bucket, the Device stops transmitting until enough tokens are
generated.
• If not enough tokens are available, the Device treats the packet in either one of the following
ways:
In traffic shaping:
• Holds it in the queue until enough tokens are available in the bucket.
In traffic policing:
• Drops it.
• Transmits it but adds a DSCP mark. The Device may drop these marked packets if the network
is overloaded.
Configure the bucket size to be equal to or less than the amount of the bandwidth that the interface
can support. It does not help if you set it to a bucket size over the interface’s capability. The smaller
the bucket size, the lower the data transmission rate and that may cause outgoing packets to be
dropped. A larger transmission rate requires a big bucket size. For example, use a bucket size of 10
kbytes to get the transmission rate up to 10 Mbps.
Single Rate Three Color Marker
The Single Rate Three Color Marker (srTCM, defined in RFC 2697) is a type of traffic policing that
identifies packets by comparing them to one user-defined rate, the Committed Information Rate
(CIR), and two burst sizes: the Committed Burst Size (CBS) and Excess Burst Size (EBS).
6
6
4
100110
100100
100010
100000
5
101110
101000
7
7
6
110000
111000
7
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)
Содержание VWG1312-B10A
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Страница 8: ...Contents Overview VMG1312 B10A User s Guide 8 Troubleshooting 291 ...
Страница 18: ...Table of Contents VMG1312 B10A User s Guide 18 ...
Страница 19: ...19 PART I User s Guide ...
Страница 20: ...20 ...
Страница 34: ...Chapter 2 The Web Configurator VMG1312 B10A User s Guide 34 ...
Страница 39: ...Chapter 4 Tutorials VMG1312 B10A User s Guide 39 7 Click Apply to save your settings ...
Страница 79: ...79 PART II Technical Reference ...
Страница 80: ...80 ...
Страница 168: ...Chapter 9 Routing VMG1312 B10A User s Guide 168 ...
Страница 186: ...Chapter 10 Quality of Service QoS VMG1312 B10A User s Guide 186 ...
Страница 212: ...Chapter 13 Interface Group VMG1312 B10A User s Guide 212 ...
Страница 228: ...Chapter 15 Firewall VMG1312 B10A User s Guide 228 ...
Страница 234: ...Chapter 17 Parental Control VMG1312 B10A User s Guide 234 ...
Страница 244: ...Chapter 19 Certificates VMG1312 B10A User s Guide 244 ...
Страница 248: ...Chapter 20 Log VMG1312 B10A User s Guide 248 ...
Страница 252: ...Chapter 21 Traffic Status VMG1312 B10A User s Guide 252 ...
Страница 258: ...Chapter 24 IGMP Status VMG1312 B10A User s Guide 258 ...
Страница 262: ...Chapter 25 xDSL Statistics VMG1312 B10A User s Guide 262 ...
Страница 264: ...Chapter 26 User Account VMG1312 B10A User s Guide 264 ...
Страница 270: ...Chapter 29 TR 064 VMG1312 B10A User s Guide 270 ...
Страница 274: ...Chapter 30 Time Settings VMG1312 B10A User s Guide 274 ...
Страница 280: ...Chapter 32 Logs Setting VMG1312 B10A User s Guide 280 ...
Страница 298: ...Chapter 36 Troubleshooting VMG1312 B10A User s Guide 298 ...
Страница 338: ...Appendix C Pop up Windows JavaScripts and Java Permissions VMG1312 B10A User s Guide 338 ...
Страница 352: ...Appendix D Wireless LANs VMG1312 B10A User s Guide 352 ...
Страница 368: ...Appendix G Legal Information VMG1312 B10A User s Guide 368 ...
Страница 376: ...VMG1312 B10A User s Guide 376 Index ...
Страница 377: ...Index VMG1312 B10A User s Guide 377 ...
Страница 378: ...VMG1312 B10A User s Guide 378 Index ...