Users Guide

11 Data Center Bridging (DCB)......................................................................................................................246
Ethernet Enhancements in Data Center Bridging..................................................................................................... 246
Priority-Based Flow Control....................................................................................................................................247
Enhanced Transmission Selection..........................................................................................................................248
Data Center Bridging Exchange Protocol (DCBx)...............................................................................................249
Data Center Bridging in a Trac Flow.................................................................................................................. 250
Enabling Data Center Bridging.....................................................................................................................................250
DCB Maps and its Attributes.................................................................................................................................. 251
Data Center Bridging: Default Conguration.............................................................................................................. 251
Conguring Priority-Based Flow Control....................................................................................................................252
Conguring Lossless Queues................................................................................................................................. 253
Conguring PFC in a DCB Map................................................................................................................................... 254
PFC Conguration Notes........................................................................................................................................254
PFC Prerequisites and Restrictions.......................................................................................................................255
Applying a DCB Map on a Port....................................................................................................................................255
Conguring PFC without a DCB Map.........................................................................................................................256
Priority-Based Flow Control Using Dynamic Buer Method................................................................................... 256
Pause and Resume of Trac..................................................................................................................................256
Buer Sizes for Lossless or PFC Packets.............................................................................................................257
Shared headroom for lossless or PFC packets...........................................................................................................257
Example Scenario.................................................................................................................................................... 258
Conguring Shared Head Room Buer................................................................................................................ 259
Viewing Shared Head Room Usage.......................................................................................................................259
Monitoring Buer Statistics for Tracking Purposes............................................................................................ 260
Behavior of Tagged Packets.........................................................................................................................................260
SNMP Support for PFC and Buer Statistics Tracking............................................................................................ 261
Performing PFC Using DSCP Bits Instead of 802.1p Bits......................................................................................... 261
Conguration Example for DSCP and PFC Priorities................................................................................................262
Using PFC to Manage Converged Ethernet Trac...................................................................................................262
Generation of PFC for a Priority for Untagged Packets...........................................................................................262
Congure Enhanced Transmission Selection..............................................................................................................263
Creating an ETS Priority Group..............................................................................................................................263
ETS Operation with DCBx......................................................................................................................................264
Conguring ETS in a DCB Map..............................................................................................................................264
Hierarchical Scheduling in ETS Output Policies.........................................................................................................266
Using ETS to Manage Converged Ethernet Trac...................................................................................................266
Applying DCB Policies in a Switch Stack.................................................................................................................... 266
Congure a DCBx Operation........................................................................................................................................266
DCBx Operation....................................................................................................................................................... 267
DCBx Port Roles...................................................................................................................................................... 267
DCB Conguration Exchange................................................................................................................................ 268
Conguration Source Election............................................................................................................................... 269
Propagation of DCB Information........................................................................................................................... 269
Auto-Detection and Manual Conguration of the DCBx Version.......................................................................270
DCBx Example..........................................................................................................................................................270
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