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Although Dell EMC Networking OS allows you to change the default dot1p priority-queue assignments (refer to Setting
dot1p Priorities for Incoming Traffic), DCB policies applied to an interface may become invalid if you reconfigure dot1p-
queue mapping. If the configured DCB policy remains valid, the change in the dot1p-queue assignment is allowed.
NOTE: Although, each port on the S4810, S4820T, and S5000 devices support 8 QoS queues, you can configure only 4
QoS queues (0-3) to manage data traffic. The remaining 4 queues (4-7) are reserved for control traffic.
dot1p Value in
the Incoming
Frame
Egress Queue Assignment
0 0
1 0
2 0
3 1
4 2
5 3
6 3
7 3
dot1p Value in
the Incoming
Frame
Egress Queue Assignment
0 2
1 0
2 1
3 3
4 4
5 5
6 6
7 7
Configuring the Dynamic Buffer Method
Priority-based flow control using dynamic buffer spaces is supported on the switch.
To configure the dynamic buffer capability, perform the following steps:
1. Enable the DCB application. By default, DCB is enabled and link-level flow control is disabled on all interfaces.
CONFIGURATION mode
dcb enable
2. Configure the shared PFC buffer size and the total buffer size. A maximum of 4 lossless queues are supported.
CONFIGURATION mode
dcb pfc-shared-buffer-size value
dcb pfc-total-buffer-size value
The buffer size range is from 0 to 3399. Default is 3088.
3. Configure the number of PFC queues.
CONFIGURATION mode
dcb enable pfc-queues pfc-queues
Data Center Bridging (DCB)
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