Loss priority settings help determine which packets are
dropped from the network during periods of congestion. The software
supports multiple packet loss priority (PLP) designations: low and high. (In addition, medium-low and medium-high PLPs are supported when you configure tricolor
marking.) You can set PLP by configuring a behavior aggregate or multifield
classifier.
A drop-profile map examines the loss priority setting of an
outgoing packet: high, medium-high, medium-low, low, or any.
Obviously, low, medium-low, medium-high, and high are relative terms, which by themselves have no meaning. Drop profiles
define the meanings of the loss priorities. In the following example,
the low-drop drop profile defines the meaning of low PLP as a 10 percent drop probability when the fill level is
75 percent and a 40 percent drop probability when the fill
level is 95 percent. The high-drop drop profile defines
the meaning of high PLP as a 50 percent drop probability
when the fill level is 25 percent and a 90 percent drop
probability when the fill level is 50 percent.
The following example procedure, configures a scheduler
that includes two drop-profile maps, which specify that packets are
evaluated by the low-drop drop profile if they have a low loss priority and are from any protocol. Packets are evaluated
by the high-drop drop profile if they have a high loss priority and are from any protocol.
- Create the low drop profile.
[edit]
user@host# edit class-of-service drop-profiles low-drop
- Specify values for interpolating the relationship between
the queue fill level and drop probability for the low drop profile.
[edit class-of-service drop-profiles low-drop]
user@host# edit interpolate
user@host# set drop-probability [10 40]
user@host# set fill-level [75 95]
- Crate the high drop profile.
[edit class-of-service drop-profiles]
user@host# edit high-drop
- Specify values for interpolating the relationship between
the queue fill level and drop probability for the high drop profile.
[edit class-of-service drop-profiles high-drop]
user@host# edit interpolate
user@host# set drop-probability [50 90]
user@host# set fill-level [25 50]
- Specify the scheduler name.
[edit class-of-service]
user@host# edit schedulers best effort
- Define the loss-priority for each low drop profile.
[edit class-of-service schedulers best-effort]
user@host# set drop-profile-map loss-priority low protocol any drop-profile low-drop
- Define the loss-priority for each high drop profile.
[edit class-of-service schedulers best-effort]
user@host# set drop-profile-map loss-priority high protocol any drop-profile high-drop
- Verify your configuration.
[edit class-of-service]
user@host# show
drop-profiles {
low-drop {
interpolate {
fill-level [ 75 95 ];
drop-probability [ 10 40 ];
}
}
high-drop {
interpolate {
fill-level [ 25 50 ];
drop-probability [ 50 90 ];
}
}
}
schedulers {
best-effort {
drop-profile-map loss-priority low protocol any drop-profile low-drop;
drop-profile-map loss-priority high protocol any drop-profile high-drop;
}
}
- Save your configuration.
[edit class-of-service]
user@host# commit
