Administrator Guide

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
The number of ports supported based on lossless queues configured depends on the buffer. The default number of PFC
queues in the system is two.
For each priority, you can specify the shared buffer threshold limit, the ingress buffer size, buffer limit for pausing the
acceptance of packets, and the buffer offset limit for resuming the acceptance of received packets.
4. Configure the profile name for the DCB buffer threshold
CONFIGURATION mode
dcb-buffer-threshold dcb-buffer-threshold
5.
DCB-BUFFER-THRESHOLD mode
priority 0 buffer-size 52 pause-threshold 16 resume-offset 10 shared-threshold-weight 7
6. Assign the DCB policy to the DCB buffer threshold profile on stack ports.
CONFIGURATION mode
DellEMC(conf)# dcb-policy buffer-threshold stack-unit all stack-ports all dcb-policy-name
7. Assign the DCB policy to the DCB buffer threshold profile on interfaces. This setting takes precedence over the default
buffer-threshold setting.
INTERFACE mode
dcb-policy buffer-threshold dcb-buffer-threshold
8. Configuring Global total buffer size on stack ports.
CONFIGURATION mode
dcb pfc-total-buffer-size buffer-size stack-unit all port-set {port-pipe |all}
Port-set number range is from 0 to 3.
Sample DCB Configuration
The following shows examples of using PFC and ETS to manage your data center traffic.
In the following example:
● Incoming SAN traffic is configured for priority-based flow control.
● Outbound LAN, IPC, and SAN traffic is mapped into three ETS priority groups and configured for enhanced traffic selection
(bandwidth allocation and scheduling).
● One lossless queue is used.
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Data Center Bridging (DCB)