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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.
9.3.4.2 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.
Figure 85
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 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 priorities of forwarding.
Resources can then be allocated according to the DSCP values and the configured
policies.
9.3.4.3 ToS (Type of Service) and WMM QoS
The DSCP value of outgoing packets is between 0 and 255. 0 is the default
priority. WMM QoS checks the DSCP value in the header of data packets. It gives
the traffic a priority according to this number.
In order to control which priority level is given to traffic, the device sending the
traffic must set the DSCP value in the header. If the DSCP value is not specified,
then the traffic is treated as best-effort. This means the wireless clients and the
devices with which they are communicating must both set the DSCP value in order
to make the best use of WMM QoS. A Voice over IP (VoIP) device for example may
allow you to define the DSCP value.
DSCP
(6-bit)
Unused
(2-bit)
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Страница 8: ...Safety Warnings NWA 3500 NWA 3550 User s Guide 8...
Страница 10: ...Contents Overview NWA 3500 NWA 3550 User s Guide 10...
Страница 20: ...Table of Contents NWA 3500 NWA 3550 User s Guide 20...
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Страница 40: ...Chapter 2 The Web Configurator NWA 3500 NWA 3550 User s Guide 40...
Страница 80: ...Chapter 3 Tutorial NWA 3500 NWA 3550 User s Guide 80...
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Страница 92: ...Chapter 5 Management Mode NWA 3500 NWA 3550 User s Guide 92...
Страница 108: ...Chapter 6 AP Controller Mode NWA 3500 NWA 3550 User s Guide 108...
Страница 144: ...Chapter 8 Wireless Configuration NWA 3500 NWA 3550 User s Guide 144...
Страница 168: ...Chapter 10 Wireless Security Screen NWA 3500 NWA 3550 User s Guide 168...
Страница 182: ...Chapter 13 MAC Filter Screen NWA 3500 NWA 3550 User s Guide 182...
Страница 186: ...Chapter 14 IP Screen NWA 3500 NWA 3550 User s Guide 186...
Страница 194: ...Chapter 15 Rogue AP Detection NWA 3500 NWA 3550 User s Guide 194...
Страница 216: ...Chapter 17 Internal RADIUS Server NWA 3500 NWA 3550 User s Guide 216...
Страница 244: ...Chapter 19 Log Screens NWA 3500 NWA 3550 User s Guide 244...
Страница 270: ...Chapter 21 Load Balancing NWA 3160 Series User s Guide 270...
Страница 274: ...Chapter 22 Dynamic Channel Selection NWA 3160 Series User s Guide 274...
Страница 286: ...Chapter 23 Maintenance NWA 3500 NWA 3550 User s Guide 286...
Страница 287: ...287 PART III Troubleshooting and Specifications Troubleshooting 289 Product Specifications 297...
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Страница 296: ...Chapter 24 Troubleshooting NWA 3500 NWA 3550 User s Guide 296...
Страница 304: ...304...
Страница 398: ...Appendix F Text File Based Auto Configuration NWA 3500 NWA 3550 User s Guide 398...
Страница 408: ...Index NWA 3500 NWA 3550 User s Guide 408...