Users Guide

11 Data Center Bridging (DCB)..................................................................................................................... 250
Ethernet Enhancements in Data Center Bridging..................................................................................................... 250
Priority-Based Flow Control.................................................................................................................................... 251
Enhanced Transmission Selection..........................................................................................................................252
Data Center Bridging Exchange Protocol (DCBx)...............................................................................................253
Data Center Bridging in a Trac Flow.................................................................................................................. 254
Enabling Data Center Bridging.....................................................................................................................................254
DCB Maps and its Attributes................................................................................................................................. 255
Data Center Bridging: Default Conguration..............................................................................................................256
Conguring Priority-Based Flow Control....................................................................................................................256
Conguring Lossless Queues..................................................................................................................................257
Conguring PFC in a DCB Map................................................................................................................................... 259
PFC Conguration Notes....................................................................................................................................... 259
PFC Prerequisites and Restrictions.......................................................................................................................260
Applying a DCB Map on a Port....................................................................................................................................260
Conguring PFC without a DCB Map..........................................................................................................................261
Conguring Lossless QueuesExample:.................................................................................................................. 261
Conguring PFC Asymmetric.......................................................................................................................................262
Priority-Based Flow Control Using Dynamic Buer Method....................................................................................263
Pause and Resume of Trac..................................................................................................................................263
Buer Sizes for Lossless or PFC Packets............................................................................................................ 263
Behavior of Tagged Packets.........................................................................................................................................264
Conguration Example for DSCP and PFC Priorities................................................................................................264
SNMP Support for PFC and Buer Statistics Tracking........................................................................................... 265
Performing PFC Using DSCP Bits Instead of 802.1p Bits.........................................................................................265
PFC and ETS Conguration Examples........................................................................................................................266
Using PFC to Manage Converged Ethernet Trac.................................................................................................. 266
Operations on Untagged Packets................................................................................................................................266
Generation of PFC for a Priority for Untagged Packets........................................................................................... 267
Congure Enhanced Transmission Selection..............................................................................................................267
ETS Prerequisites and Restrictions........................................................................................................................267
Creating an ETS Priority Group..............................................................................................................................267
ETS Operation with DCBx......................................................................................................................................269
Conguring Bandwidth Allocation for DCBx CIN................................................................................................ 269
Conguring ETS in a DCB Map..............................................................................................................................270
Hierarchical Scheduling in ETS Output Policies..........................................................................................................271
Using ETS to Manage Converged Ethernet Trac................................................................................................... 272
Applying DCB Policies in a Switch Stack.................................................................................................................... 272
Congure a DCBx Operation........................................................................................................................................ 272
DCBx Operation....................................................................................................................................................... 272
DCBx Port Roles...................................................................................................................................................... 273
DCB Conguration Exchange.................................................................................................................................274
Conguration Source Election................................................................................................................................274
Propagation of DCB Information............................................................................................................................275
Auto-Detection and Manual Conguration of the DCBx Version...................................................................... 275
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