ZyXEL MES3500-24F User Guide - Page 269

Two Rate Three Color Marker Traffic Policing

Page 269 highlights

Chapter 35 Differentiated Services 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 152 DiffServ Network A PGS B P - Platinum G - Gold S - Silver B - Bronze SGP P S B B S GP P 35.2 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. • Green (low loss priority level) packets are forwarded. TRTCM operates in one of two modes: color-blind or color-aware. In color-blind mode, packets are marked based on evaluating against the PIR and CIR regardless of if they have previously been marked or not. In the color-aware mode, packets are marked based on both existing color and evaluation against the PIR and CIR. If the packets do not match any of colors, then the packets proceed unchanged. MES3500-24/24F User's Guide 269

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Chapter 35 Differentiated Services
MES3500-24/24F User’s Guide
269
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 152
DiffServ Network
35.2
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.
Green (low loss priority level) packets are forwarded.
TRTCM operates in one of two modes: color-blind or color-aware. In color-blind mode, packets are
marked based on evaluating against the PIR and CIR regardless of if they have previously been
marked or not. In the color-aware mode, packets are marked based on both existing color and
evaluation against the PIR and CIR. If the packets do not match any of colors, then the packets
proceed unchanged.
G
S
B
P
S
B
B
G
P
P
S
P - Platinum
G - Gold
S - Silver
B - Bronze
G
P
P
S
A