Users Guide

NOTE: Dell Networking does not recommend mapping all ingress trac to a single queue when using PFC and ETS.
However, Dell Networking does recommend using Ingress trac classication using the service-class dynamic
dot1p command (honor dot1p) on all DCB-enabled interfaces. If you use L2 class maps to map dot1p priority trac to
egress queues, take into account the default dot1p-queue assignments in the following table and the maximum number of
two lossless queues supported on a port (refer to
Conguring Lossless Queues).
Although Dell Networking OS allows you to change the default dot1p priority-queue assignments (refer to Setting dot1p
Priorities for Incoming Trac), DCB policies applied to an interface may become invalid if you recongure dot1p-queue
mapping. If the congured 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 congure only 4
QoS queues (0-3) to manage data trac. The remaining 4 queues (4-7) are reserved for control trac.
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
Conguring the Dynamic Buer Method
Priority-based ow control using dynamic buer spaces is supported on the switch.
To congure the dynamic buer capability, perform the following steps:
1. Enable the DCB application. By default, DCB is enabled and link-level ow control is disabled on all interfaces.
CONFIGURATION mode
dcb enable
2. Congure the shared PFC buer size and the total buer size. A maximum of 4 lossless queues are supported.
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Data Center Bridging (DCB)