Deployment Guide

• Enhanced transmission selection
• Data center bridging exchange protocol
• FCoE initialization protocol (FIP) snooping
DCB processes virtual local area network (VLAN)-tagged packets and dot1p priority values. Untagged packets are treated with a dot1p
priority of 0.
For DCB to operate eectively, you can classify ingress trac according to its dot1p priority so that it maps to dierent data queues. The
dot1p-queue assignments used are shown in the following table.
To enable DCB, enable either the iSCSI optimization conguration or the FCoE conguration. For information to congure iSCSI
optimization, refer to iSCSI Optimization. For information to congure FCoE, refer to Fibre Channel over Ethernet.
To enable DCB with PFC buers on a switch, enter the following commands, save the conguration, and reboot the system to allow the
changes to take eect.
1 Enable DCB.
CONFIGURATION mode
dcb enable
2 Set PFC buering on the DCB stack unit.
CONFIGURATION mode
dcb stack-unit all pfc-buffering pfc-ports 64 pfc-queues 2
NOTE
: To save the pfc buering conguration changes, save the conguration and reboot the
system.
NOTE: Dell Networking OS Behavior: DCB is not supported if you enable link-level ow control on one or more interfaces. For
more information, refer to Flow Control Using Ethernet Pause Frames.
Conguring DCB Maps and its Attributes
This topic contains the following sections that describe how to congure a DCB map, apply the congured DCB map to a port, congure
PFC without a DCB map, and congure lossless queues.
DCB Map: Conguration Procedure
A DCB map consists of PFC and ETS parameters. By default, PFC is not enabled on any 802.1p priority and ETS allocates equal bandwidth
to each priority. To congure user-dened PFC and ETS settings, you must create a DCB map.
1 Enter global conguration mode to create a DCB map or edit PFC and ETS settings.
CONFIGURATION mode
dcb-map name
2 Congure the PFC setting (on or o) and the ETS bandwidth percentage allocated to trac in each priority group, or whether the
priority group trac should be handled with strict priority scheduling. You can enable PFC on a maximum of two priority queues on an
interface. Enabling PFC for dot1p priorities makes the corresponding port queue lossless. The sum of all allocated bandwidth
percentages in all groups in the DCB map must be 100%. Strict-priority trac is serviced rst. Afterwards, bandwidth allocated to
other priority groups is made available and allocated according to the specied percentages. If a priority group does not use its
allocated bandwidth, the unused bandwidth is made available to other priority groups.
DCB MAP mode
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Data Center Bridging (DCB)