RED Drop Profiles Overview on ACX Series Routers
You can configure two parameters to control congestion at the output stage. The first parameter defines the delay-buffer bandwidth, which provides packet buffer space to absorb burst traffic up to the specified duration of delay. When the specified delay buffer becomes full, packets with 100 percent drop probability are dropped from the head of the buffer.
The second parameter defines the drop probabilities across the range of delay-buffer occupancy, supporting the random early detection (RED) process. When the number of packets queued is greater than the ability of the router to empty a queue, the queue requires a method for determining which packets to drop from the network. To address this, you can enable RED on individual queues.
Depending on the drop probabilities, RED might drop many packets long before the buffer becomes full, or it might drop only a few packets even if the buffer is almost full.
A drop profile is a mechanism of RED that defines parameters that allow packets to be dropped from the network. Drop profiles define the meanings of the loss priorities.
When you configure drop profiles, there are two important values: the queue fullness and the drop probability. The queue fullness represents a percentage of the memory used to store packets in relation to the total amount that has been allocated for that specific queue. Similarly, the drop probability is a percentage value that correlates to the likelihood that an individual packet is dropped from the network.
You specify drop probabilities at the [edit class-of-service drop-profiles
drop profile-name
fill-level
percentage
drop-probability
percentage;]
class-of-service (COS) configuration
hierarchy and reference them in each scheduler configuration. For each scheduler, you
can configure four drop profiles as high-tcp,
medium-high-tcp, low-tcp,
non-tcp
. Two fill levels can be specified in each
drop-profile map. The drop probability associated with the least fill level must be set
as zero, otherwise the CLI command will be rejected during commit check.
Platform-Specific RED Drop Profile Behavior
Use the following table to review platform-specific behaviors for your platform:
Platform |
Difference |
---|---|
ACX5448 |
|
ACX6360 |
|
ACX7024 |
|