Peak Mode - Juniper ACX1000 Configuration Manual

ACX Series Universal Access Router Configuration Guide
Policers use a token bucket algorithm to enforce a limit on an average transmit or receive
rate of traffic at an interface while allowing bursts of traffic up to a maximum value based
on the configured bandwidth limit and configured burst size. The token bucket algorithm
offers more flexibility than a leaky bucket algorithm in that you can allow a specified
traffic burst before starting to discard packets or apply a penalty such as packet
output-queuing priority or packet-drop priority. Following are the main components of
the token bucket algorithm:
An arriving packet complies with the bandwidth-guarantee mode if tokens are present
in the peak burst size (PBS) of either the parent policer or the committed burst size (CBS)
of the child policer. If sufficient tokens are not present in the PBS or CBS of either of the
parent or child policers respectively, the packet does not conform to the guarantee mode
of the hierarchical policer working. In such a case, the child policer rate is guaranteed for
the member flows. The following table describes the different scenarios of color-coding
for micro-flow and macro-flow policers and the resultant color or priority that is assigned:
Micro-Color
Green
Green
Red
Red

Peak Mode

This mode, also called bandwidth-protection mode, is used when the micro-flow policer
is used to specify the maximum amount of the aggregate parent policer bandwidth that
the micro-flow can use. This mode is used to protect a given micro-flow from starving
the other flows. Even when the other micro-flows contain no traffic (the available
aggregate bandwidth rate is greater than the rate of the particular micro-flow, the
micro-flow cannot use more than the rate configured on its micro-flow policer.
Consider a sample scenario in which the total maximum allowed rate (PIR) for a user is
100 Mbps. A total of four services or applications called expedited forwarding (EF), Gold,
Silver and Bronze are defined for the peak or bandwidth-restriction mode of the policer
924
The bucket represents a rate-limiting function of the policer on the interface input or
output traffic.
Each token in the bucket represents a "credit" for some number of bits, and tokens in
the bucket are "cashed in" for the ability to receive or transmit traffic that conforms to
a rate limit configured for the policer.
The token arrival rate is a periodic allocation of tokens into the token bucket that is
calculated from the configured bandwidth limit.
The token bucket depth defines the capacity of the bucket in bytes. Tokens that are
allocated after the bucket reaches capacity are not able to be stored and used.
Macro-Color
Green
Red
Green
Red
Copyright © 2017, Juniper Networks, Inc.
Result
Green
Green
Green
Red