Users Guide

The configuration shows how to enable Deep Buffer mode in a switch.
OS10# configure terminal
OS10(config)# hardware deep-buffer-mode
% Warning: Deep buffer mode configuration will be applied only after a save and reload.
OS10(config)# exit
OS10# write memory
OS10# reload
Proceed to reboot the system? [confirm yes/no]: Y
To view Deep Buffer mode status, use the show hardware deep-buffer-mode command. The show command output
displays the status of Deep Buffer mode in the current boot and the next boot.
The following is Deep Buffer mode status before enabling it, the default setting:
OS10# show hardware deep-buffer-mode
Deep Buffer Mode Configuration Status
-------------------------------------------
Current-boot Settings : Disabled
Next-boot Settings : Disabled
The following is Deep Buffer mode status after saving the configuration in the startup configuration:
OS10# show hardware deep-buffer-mode
Deep Buffer Mode Configuration Status
-------------------------------------------
Current-boot Settings : Disabled
Next-boot Settings : Enabled
The following is Deep Buffer mode status after the switch reloads:
OS10# show hardware deep-buffer-mode
Deep Buffer Mode Configuration Status
-------------------------------------------
Current-boot Settings : Enabled
Next-boot Settings : Enabled
Congestion avoidance
Congestion avoidance anticipates and takes necessary actions to avoid congestion. The following mechanisms avoid congestion:
● Tail drop—Packets are buffered at traffic queues. When the buffers are exhausted or reach the configured threshold,
excess packets drop. By default, OS10 uses tail drop for congestion avoidance.
● Random early detection (RED)—In tail drop, different flows are not considered in buffer utilization. When multiple hosts
start retransmission, tail drop causes TCP global re-synchronization. Instead of waiting for the queue to get filled up
completely, RED starts dropping excess packets with a certain drop-probability when the average queue length exceeds the
configured minimum threshold. The early drop ensures that only some of TCP sources slow down, which avoids global TCP
re-synchronization.
● Weighted random early detection (WRED)—This allows different drop-probabilities and thresholds for each color — red,
yellow, green — of traffic. You can configure the drop characteristics for three different flows by assigning the colors to the
flow. Assign colors to a particular flow or traffic using various methods, such as ingress policing, qos input policy-maps, and
so on.
● Explicit congestion notification (ECN)—This is an extension of WRED. Instead of dropping the packets when the
average queue length crosses the minimum threshold values, ECN marks the Congestion Experienced (CE) bit of the ECN
field in a packet as ECN-capable traffic (ECT).
1. Configure a WRED profile in CONFIGURATION mode.
OS10(config)# wred example-wred-prof
Quality of service
1331