MGS-3712/MGS-3012F User’s Guide
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25
Two Rate Three Color Marker
This chapter describes how Differentiated Services (DiffServ) fits into a quality of service
strategy and shows you how to configure Two Rate Three Color Marker traffic policing on the
Switch.
25.1 DiffServ Overview
Quality of Service (QoS) is used to prioritize source-to-destination traffic flows. All packets in
the flow are given the same priority. You can use CoS (class of service) to give different
priorities to different packet types.
DiffServ is a class of service (CoS) model that marks packets so that they receive specific per-
hop treatment at DiffServ-compliant network devices along the route based on the application
types and traffic flow. Packets are marked with DiffServ Code Points (DSCPs) indicating the
level of service desired. This allows the intermediary DiffServ-compliant network devices to
handle the packets differently depending on the code points without the need to negotiate
paths or remember state information for every flow. In addition, applications do not have to
request a particular service or give advanced notice of where the traffic is going.
25.1.1 DSCP and Per-Hop Behavior
DiffServ defines a new DS (Differentiated Services) field to replace the Type of Service (ToS)
field in the IP header. The DS field contains a 6-bit DSCP field which can define up to 64
service levels and the remaining 2 bits are defined as currently unused (CU). The following
figure illustrates the DS field.
Figure 121
DiffServ: Differentiated Service Field
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 PHB (Per-Hop Behavior), that each packet gets as it is
forwarded across the DiffServ network. Based on the marking rule different kinds of traffic
can be marked for different priorities of forwarding. Resources can then be allocated
according to the DSCP values and the configured policies.
DSCP (6 bits)
CU (2 bits)
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Страница 82: ...Chapter 7 Basic Setting MGS 3712 MGS 3012F User s Guide 82 ...
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Страница 132: ...Chapter 15 Link Aggregation MGS 3712 MGS 3012F User s Guide 132 ...
Страница 142: ...Chapter 17 Port Security MGS 3712 MGS 3012F User s Guide 142 ...
Страница 148: ...Chapter 18 Classifier MGS 3712 MGS 3012F User s Guide 148 Figure 80 Classifier Example ...
Страница 153: ...Chapter 19 Policy Rule MGS 3712 MGS 3012F User s Guide 153 Figure 83 Policy Example ...
Страница 154: ...Chapter 19 Policy Rule MGS 3712 MGS 3012F User s Guide 154 ...
Страница 169: ...Chapter 21 Multicast MGS 3712 MGS 3012F User s Guide 169 Figure 96 MVR Group Configuration Example ...
Страница 170: ...Chapter 21 Multicast MGS 3712 MGS 3012F User s Guide 170 ...
Страница 184: ...Chapter 22 Authentication Accounting MGS 3712 MGS 3012F User s Guide 184 ...
Страница 214: ...Chapter 25 Two Rate Three Color Marker MGS 3712 MGS 3012F User s Guide 214 ...
Страница 215: ...215 PART IV IP Application Static Route 217 DHCP 221 ...
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Страница 220: ...Chapter 26 Static Route MGS 3712 MGS 3012F User s Guide 220 ...
Страница 227: ...Chapter 27 DHCP MGS 3712 MGS 3012F User s Guide 227 Figure 134 DHCP Relay for Two VLANs Configuration Example ...
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Страница 256: ...Chapter 30 Diagnostic MGS 3712 MGS 3012F User s Guide 256 ...
Страница 260: ...Chapter 31 Syslog MGS 3712 MGS 3012F User s Guide 260 ...
Страница 273: ...273 PART VI Troubleshooting Product Specifications Troubleshooting 275 Product Specifications 279 ...
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Страница 285: ...285 PART VII Appendices and Index Common Services 287 Legal Information 291 Customer Support 295 Index 301 ...
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Страница 290: ...Appendix A Common Services MGS 3712 MGS 3012F User s Guide 290 ...
Страница 294: ...Appendix B Legal Information MGS 3712 MGS 3012F User s Guide 294 ...
Страница 308: ...Index MGS 3712 MGS 3012F User s Guide 308 ...