Policy Framework Configuration Guide - Juniper Networks

Junos 10.4 Policy Framework Configuration Guide
• show interfaces statistics command in the Junos Interfaces Command Reference
• show policer command in the Junos Routing Protocols and Policies Command Reference
Single-Rate Three-Color Policers
• Single-Rate Three-Color Policer Overview on page 286
• Configuring a Single-Rate Three-Color Policer on page 287
Single-Rate Three-Color Policer Overview
Single-rate three-color policing uses a bandwidth limit (also called a committed
information rate (CIR)), a committed burst size, and an excess burst size. The policer
classifies traffic into three groups: traffic that conforms to the bandwidth limit or the
committed burst size, traffic that exceeds the bandwidth limit and committed burst size
but conforms to the excess burst size, and traffic that exceeds the excess burst size.
Each category is associated with an action. For traffic that conforms to the bandwidth
limit or the committed burst size (also called green traffic), the action is to mark the
packet with an implicit low loss priority and transmit the packet. For traffic that exceeds
the bandwidth limit and committed burst size but conforms to the excess burst size (also
called yellow traffic), the action is to mark the packet with an implicit loss priority of
medium-high and then transmit the packet. For traffic that exceeds the excess burst
size, the action is to mark the packet with an implicit loss priority of high and, optionally,
to discard the packet. If congestion occurs downstream, the packets with higher loss
priority are more likely to be discarded.
NOTE: The discard action for a tricolor marking policer for a firewall filter is
supported on the M120, M320 with Enhanced-III FPCs, M7i and M10i with the
Enhanced CFEB (CFEB-E), and the MX Series routers, so it is not necessary
to include the logical-interface-policer statement for them.
The following configuration demonstrates how the policer works in a sample scenario.
firewall {
three-color-policer srTCM1-ca {
logical-interface-policer;
action {
loss-priority high then discard;
}
single-rate {
color-aware;
committed-information-rate 40m;
committed-burst-size 100k;
excess-burst-size 200k;
}
}
}
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