GS-2750 User’s Guide
225
C
H A P T E R
28
Differentiated Services
This chapter shows you how to configure Differentiated Services (DiffServ) on the Switch.
28.1 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.
28.1.1 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 115
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)
Содержание GS-2750
Страница 2: ......
Страница 7: ...Safety Warnings GS 2750 User s Guide 7 This product is recyclable Dispose of it properly ...
Страница 8: ...Safety Warnings GS 2750 User s Guide 8 ...
Страница 26: ...List of Figures GS 2750 User s Guide 26 ...
Страница 32: ...32 ...
Страница 40: ...Chapter 2 Hardware Installation and Connection GS 2750 User s Guide 40 ...
Страница 48: ...48 ...
Страница 58: ...Chapter 4 The Web Configurator GS 2750 User s Guide 58 ...
Страница 64: ...Chapter 5 Initial Setup Example GS 2750 User s Guide 64 ...
Страница 70: ...Chapter 6 System Status and Port Statistics GS 2750 User s Guide 70 ...
Страница 82: ...Chapter 7 Basic Setting GS 2750 User s Guide 82 ...
Страница 84: ...84 ...
Страница 115: ...Chapter 11 Spanning Tree Protocol GS 2750 User s Guide 115 Figure 52 Advanced Application Spanning Tree Protocol MSTP ...
Страница 120: ...Chapter 11 Spanning Tree Protocol GS 2750 User s Guide 120 ...
Страница 134: ...Chapter 15 Link Aggregation GS 2750 User s Guide 134 ...
Страница 144: ...Chapter 17 Port Security GS 2750 User s Guide 144 ...
Страница 155: ...Chapter 19 Policy Rule GS 2750 User s Guide 155 Figure 73 Policy Example example ...
Страница 156: ...Chapter 19 Policy Rule GS 2750 User s Guide 156 ...
Страница 160: ...Chapter 20 Queuing Method GS 2750 User s Guide 160 ...
Страница 166: ...Chapter 21 VLAN Stacking GS 2750 User s Guide 166 ...
Страница 194: ...Chapter 23 Authentication Accounting GS 2750 User s Guide 194 ...
Страница 219: ...219 PART IV IP Application Static Routing 221 RIP 223 Differentiated Services 225 DHCP 233 VRRP 243 ...
Страница 220: ...220 ...
Страница 232: ...Chapter 28 Differentiated Services GS 2750 User s Guide 232 ...
Страница 242: ...Chapter 29 DHCP GS 2750 User s Guide 242 ...
Страница 252: ...Chapter 30 VRRP GS 2750 User s Guide 252 ...
Страница 254: ...254 ...
Страница 278: ...Chapter 32 Access Control GS 2750 User s Guide 278 ...
Страница 280: ...Chapter 33 Diagnostic GS 2750 User s Guide 280 ...
Страница 284: ...Chapter 34 Syslog GS 2750 User s Guide 284 ...
Страница 298: ...Chapter 39 Routing Table GS 2750 User s Guide 298 ...
Страница 301: ...301 PART VI Product Specifications Product Specifications 303 ...
Страница 302: ...302 ...
Страница 309: ...309 PART VII Appendices and Index IP Addresses and Subnetting 311 Legal Information 319 Customer Support 323 Index 329 ...
Страница 310: ...310 ...
Страница 322: ...Appendix B Legal Information GS 2750 User s Guide 322 ...
Страница 328: ...Appendix C Customer Support GS 2750 User s Guide 328 ...