Reference Guide

282 | Data Center Bridging (DCB)
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Data Center Bridging: Default Configuration
Before you configure PFC and ETS on an S5000 switch (see DCB Map: Configuration Procedure), take
into account the following default settings:
• DCB is enabled (see Enabling Data Center Bridging).
• The PFC memory buffer supports up to 64 PFC-enabled ports and two lossless queues per port.
• PFC and ETS are globally enabled by default:
• The default dot1p priority-queue assignments are applied as follows:
• PFC is not applied on specific dot1p priorities.
• ETS: Equal bandwidth is assigned to each port queue and each dot1p priority in a priority group.
• To configure PFC and ETS parameters on an S5000 interface, you must specify a PFC mode and ETS
bandwidth allocation for a priority group and an 802.1p priority-to-priority group mapping in a DCB
map (see Configuring PFC and ETS in a DCB Map). No default PFC and ETS settings are applied to
Ethernet interfaces.
Enabling Data Center Bridging
DCB is enabled by default on the S5000 switch to support converged enhanced Ethernet (CEE) in a data
center network and is a prerequisite for configuring:
• Priority-based flow control
• Enhanced transmission selection
• Data center bridging exchange protocol
• FCoE transit with FIP snooping
• N-port identifier virtualization (NPIV) proxy gateway (NPG)
DCB processes VLAN-tagged packets and dot1p priority values. Untagged packets are treated with a
dot1p priority of 0.
For DCB to operate effectively, you can classify ingress traffic according to its dot1p priority so that it
maps to different data queues. The dot1p-queue assignments used are shown in Table 13-1.
To disable or re-enable DCB on an S5000 switch, enter the following commands.
802.1p value in incoming frame: 01234567
Egress queue assignment 00012333
Task Command Command Mode
Disable DCB.
no dcb enable
CONFIGURATION
Re-enable DCB.
dcb enable
CONFIGURATION