MGS-3712/MGS-3012F User’s Guide
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19
Policy Rule
This chapter shows you how to configure policy rules.
19.1 Policy Rules Overview
A classifier distinguishes traffic into flows based on the configured criteria (refer to
for more information). A policy rule ensures that a traffic flow gets the
requested treatment in the network.
19.1.1 DiffServ
DiffServ (Differentiated Services) 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.
19.1.2 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 2-bit unused field and a 6-bit DSCP field
which can define up to 64 service levels. The following figure illustrates the DS 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 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.
DSCP (6 bits)
Unused (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 ...
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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 ...