ZyXEL Communications OLT2406, User Manual

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Chapter 73 Policy Rule
OLT2406 User’s Guide
520
This example creates a policy ( Policy1 ) for the traffic flow identified via classifier Class1 (see the classifier
example in Chapter 71 on page 507 ). This policy forwards Class1 packets to port ge-5-4.
73.4 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.
73.4.1 TRTCM - Color-blind Mode
All packets are evaluated against the PIR. If a packet exceeds the PIR it is marked red. Otherwise it is
evaluated against the CIR. If it exceeds the CIR then it is marked yellow. Finally, if it is below the CIR then
it is marked green.
OLT2406(config)# policy Policy1 classifier Class1 egress-port ge-5-4
outgoing-eport
OLT2406(config)# exit
OLT2406# show policy Policy1
Policy Policy1:
Classifiers:
Class1;
Parameters:
VLAN = 1; Priority = 0; DSCP = 0; TOS = 0;
Egress Port = ge-5-4;
Mirror Port = msc-1-1;
Bandwidth = 0; Out-of-profile DSCP = 0;
Action:
Send the packet to the egress port;