Addendum

Data Center Bridging (DCB)

This chapter describes the DCB enhancements and contains the following sections:

• Managing Hardware Buffer Statistics

• Configuring WRED and ECN Attributes

• Enabling Buffer Statistics Tracking

• Configuring DCB Maps and its Attributes

• Data Center Bridging: Default Configuration

• Configuring the Dynamic Buffer Method

• Priority-Based Flow Control Using Dynamic Buffer Method

Configuring DCB Maps and its Attributes

This topic contains the following sections that describe how to configure a DCB map, apply the

configured DCB map to a port, configure PFC without a DCB map, and configure lossless queues. This

functionality is supported S4810, S4820T, S6000, I/O Aggregator, and MXL platforms.

DCB Map: Configuration 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 configure user-defined PFC and ETS settings, you

must create a DCB map.

Step Task Command Command Mode

Enter global configuration mode to create a

DCB map or edit PFC and ETS settings.

dcb-map name CONFIGURATION

Configure the PFC setting (on or off) and the

ETS bandwidth percentage allocated to traffic

in each priority group or whether priority

group traffic 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 traffic is serviced

first. Afterwards, bandwidth allocated to other

priority groups is made available and allocated

according to the specified percentages. If a

priority group does not use its allocated

bandwidth, the unused bandwidth is made

available to other priority groups.

Example: priority-group 0 bandwidth 60 pfc

off priority-group 1 bandwidth 20 pfc on

priority-group group_num

{bandwidth percentage |

strict-priority} pfc {on |

off}

DCB MAP

Data Center Bridging (DCB)