White Papers

12 Data Center Bridging (DCB)..................................................................................................................... 244
Ethernet Enhancements in Data Center Bridging......................................................................................................244
Priority-Based Flow Control................................................................................................................................... 245
Enhanced Transmission Selection..........................................................................................................................246
Data Center Bridging Exchange Protocol (DCBx)...............................................................................................247
Data Center Bridging in a Trac Flow...................................................................................................................248
Enabling Data Center Bridging..................................................................................................................................... 248
DCB Maps and its Attributes..................................................................................................................................249
Data Center Bridging: Default Conguration............................................................................................................. 250
Conguring Priority-Based Flow Control....................................................................................................................250
Conguring Lossless Queues........................................................................................................................................ 251
Conguring PFC in a DCB Map................................................................................................................................... 253
PFC Conguration Notes........................................................................................................................................253
PFC Prerequisites and Restrictions.......................................................................................................................254
Conguring PFC without a DCB Map.........................................................................................................................254
Conguring Lossless QueuesExample:..................................................................................................................254
Priority-Based Flow Control Using Dynamic Buer Method............................................................................. 256
Behavior of Tagged Packets.........................................................................................................................................257
Conguration Example for DSCP and PFC Priorities................................................................................................257
SNMP Support for PFC and Buer Statistics Tracking............................................................................................258
Performing PFC Using DSCP Bits Instead of 802.1p Bits.........................................................................................259
PFC and ETS Conguration Examples........................................................................................................................259
Using PFC to Manage Converged Ethernet Trac.................................................................................................. 259
Operations on Untagged Packets................................................................................................................................260
Generation of PFC for a Priority for Untagged Packets...........................................................................................260
Congure Enhanced Transmission Selection............................................................................................................. 260
ETS Prerequisites and Restrictions....................................................................................................................... 260
Creating an ETS Priority Group.............................................................................................................................. 261
ETS Operation with DCBx......................................................................................................................................262
Conguring Bandwidth Allocation for DCBx CIN.................................................................................................262
Conguring ETS in a DCB Map..............................................................................................................................263
Hierarchical Scheduling in ETS Output Policies......................................................................................................... 264
Using ETS to Manage Converged Ethernet Trac...................................................................................................265
Applying DCB Policies in a Switch Stack.................................................................................................................... 265
Congure a DCBx Operation........................................................................................................................................265
DCBx Operation.......................................................................................................................................................265
DCBx Port Roles......................................................................................................................................................266
DCB Conguration Exchange.................................................................................................................................267
Conguration Source Election................................................................................................................................267
Propagation of DCB Information............................................................................................................................268
Auto-Detection and Manual Conguration of the DCBx Version...................................................................... 268
DCBx Example......................................................................................................................................................... 269
DCBx Prerequisites and Restrictions.....................................................................................................................269
Conguring DCBx....................................................................................................................................................269
Verifying the DCB Conguration..................................................................................................................................273
Contents
9