
XGS-4526/4528F/4728F User’s Guide
353
C
H A P T E R
4 0
Differentiated Services
This chapter shows you how to configure Differentiated Services (DiffServ) on the
Switch.
40.1 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.
40.1.1 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 178
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
DSCP (6 bits)
CU (2 bits)
Содержание XGS-4528F
Страница 2: ......
Страница 8: ...Safety Warnings XGS 4526 4528F 4728F User s Guide 8...
Страница 24: ...Table of Contents XGS 4526 4528F 4728F User s Guide 24...
Страница 25: ...25 PART I User s Guide...
Страница 26: ...26...
Страница 32: ...Chapter 1 Getting to Know Your Switch XGS 4526 4528F 4728F User s Guide 32...
Страница 36: ...Chapter 2 Hardware Installation and Connection XGS 4526 4528F 4728F User s Guide 36...
Страница 93: ...93 PART II Technical Reference...
Страница 94: ...94...
Страница 100: ...Chapter 7 System Status and Port Statistics XGS 4526 4528F 4728F User s Guide 100...
Страница 116: ...Chapter 8 Basic Setting XGS 4526 4528F 4728F User s Guide 116...
Страница 136: ...Chapter 9 VLAN XGS 4526 4528F 4728F User s Guide 136...
Страница 140: ...Chapter 10 Static MAC Forward Setup XGS 4526 4528F 4728F User s Guide 140...
Страница 172: ...Chapter 14 Bandwidth Control XGS 4526 4528F 4728F User s Guide 172...
Страница 186: ...Chapter 17 Link Aggregation XGS 4526 4528F 4728F User s Guide 186...
Страница 196: ...Chapter 18 Port Authentication XGS 4526 4528F 4728F User s Guide 196...
Страница 214: ...Chapter 21 Policy Rule XGS 4526 4528F 4728F User s Guide 214...
Страница 258: ...Chapter 25 AAA XGS 4526 4528F 4728F User s Guide 258...
Страница 282: ...Chapter 26 IP Source Guard XGS 4526 4528F 4728F User s Guide 282...
Страница 314: ...Chapter 32 Error Disable XGS 4526 4528F 4728F User s Guide 314...
Страница 318: ...Chapter 33 Private VLAN XGS 4526 4528F 4728F User s Guide 318...
Страница 322: ...Chapter 34 Static Route XGS 4526 4528F 4728F User s Guide 322...
Страница 330: ...Chapter 36 RIP XGS 4526 4528F 4728F User s Guide 330...
Страница 386: ...Chapter 43 ARP Learning XGS 4526 4528F 4728F User s Guide 386...
Страница 396: ...Chapter 45 Maintenance XGS 4526 4528F 4728F User s Guide 396...
Страница 442: ...Chapter 49 Cluster Management XGS 4526 4528F 4728F User s Guide 442...
Страница 446: ...Chapter 50 MAC Table XGS 4526 4528F 4728F User s Guide 446...
Страница 450: ...Chapter 51 IP Table XGS 4526 4528F 4728F User s Guide 450...
Страница 454: ...Chapter 53 Routing Table XGS 4526 4528F 4728F User s Guide 454...
Страница 462: ...Chapter 55 Troubleshooting XGS 4526 4528F 4728F User s Guide 462...
Страница 472: ...Chapter 56 Product Specifications XGS 4526 4528F 4728F User s Guide 472...
Страница 480: ...Appendix B Legal Information XGS 4526 4528F 4728F User s Guide 480...