Chapter 28 Differentiated Services
GS-2750 User’s Guide
226
28.1.2 DiffServ Network Example
The following figure depicts a DiffServ network consisting of a group of directly connected
DiffServ-compliant network devices. The boundary node (
A
in
Figure 116
) in a DiffServ
network classifies (marks with a DSCP value) the incoming packets into different traffic flows
(
Platinum
,
Gold
,
Silver
,
Bronze
) based on the configured marking rules. A network
administrator can then apply various traffic policies to the traffic flows. For example, one
traffic policy would be to give higher drop precedence to one traffic flow over others. In our
example packets in the
Bronze
traffic flow are more likely to be dropped when congestion
occurs than the packets in the
Platinum
traffic flow as they move across the DiffServ network.
Figure 116
DiffServ Network
28.2 Two Rate Three Color Marker Traffic Policing
Traffic policing is the limiting of the input or output transmission rate of a class of traffic on
the basis of user-defined criteria. Traffic policing methods measure traffic flows against user-
defined criteria and identify it as either conforming, exceeding or violating the criteria.
Two Rate Three Color Marker (TRTCM, defined in RFC 2698) is a type of traffic policing
that identifies packets by comparing them to two user-defined rates: the Committed
Information Rate (CIR) and the Peak Information Rate (PIR). The CIR specifies the average
rate at which packets are admitted to the network. The PIR is greater than or equal to the CIR.
CIR and PIR values are based on the guaranteed and maximum bandwidth respectively as
negotiated between a service provider and client.
Two Rate Three Color Marker evaluates incoming packets and marks them with one of three
colors which refer to packet loss priority levels. High packet loss priority level is referred to as
red, medium is referred to as yellow and low is referred to as green. After TRTCM is
configured and DiffServ is enabled the following actions are performed on the colored
packets:
• Red (high loss priority level) packets are dropped.
• Yellow (medium loss priority level) packets are dropped if there is congestion on the
network.
G S B
P
S
B
B
G P P
S
P - Platinum
G - Gold
S - Silver
B - Bronze
G P P
S
A
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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 ...
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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 ...
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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 ...
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Страница 309: ...309 PART VII Appendices and Index IP Addresses and Subnetting 311 Legal Information 319 Customer Support 323 Index 329 ...
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Страница 322: ...Appendix B Legal Information GS 2750 User s Guide 322 ...
Страница 328: ...Appendix C Customer Support GS 2750 User s Guide 328 ...