ZyXEL Communications metrogigabit switch manual Two Rate Three Color Marker Traffic Policing, 342

Chapter 36 Differentiated Services

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.

36.1.2 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 171) 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. An example traffic policy, is 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 171 DiffServ Network

A

S G P P

	P G S B	S G P P
P - Platinum
			S
G - Gold				B
S - Silver					B
B - Bronze

36.2Two 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.

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MGS3700-12C User’s Guide