Administrator Guide

11 Data Center Bridging (DCB)......................................................................................................................247
Ethernet Enhancements in Data Center Bridging......................................................................................................247
Priority-Based Flow Control................................................................................................................................... 248
Enhanced Transmission Selection..........................................................................................................................249
Data Center Bridging Exchange Protocol (DCBx)...............................................................................................250
Data Center Bridging in a Trac Flow................................................................................................................... 251
Enabling Data Center Bridging......................................................................................................................................251
DCB Maps and its Attributes..................................................................................................................................252
Data Center Bridging: Default Conguration..............................................................................................................252
Conguring Priority-Based Flow Control....................................................................................................................253
Conguring Lossless Queues................................................................................................................................. 254
Conguring PFC in a DCB Map...................................................................................................................................255
PFC Conguration Notes....................................................................................................................................... 255
PFC Prerequisites and Restrictions.......................................................................................................................256
Applying a DCB Map on a Port....................................................................................................................................256
Conguring PFC without a DCB Map.........................................................................................................................257
Priority-Based Flow Control Using Dynamic Buer Method....................................................................................257
Pause and Resume of Trac..................................................................................................................................257
Buer Sizes for Lossless or PFC Packets............................................................................................................ 258
Shared headroom for lossless or PFC packets.......................................................................................................... 258
Example Scenario.................................................................................................................................................... 259
Conguring Shared Head Room Buer................................................................................................................ 260
Viewing Shared Head Room Usage.......................................................................................................................260
Monitoring Buer Statistics for Tracking Purposes............................................................................................. 261
Behavior of Tagged Packets..........................................................................................................................................261
SNMP Support for PFC and Buer Statistics Tracking............................................................................................262
Performing PFC Using DSCP Bits Instead of 802.1p Bits.........................................................................................262
Conguration Example for DSCP and PFC Priorities................................................................................................263
Using PFC to Manage Converged Ethernet Trac...................................................................................................263
Generation of PFC for a Priority for Untagged Packets...........................................................................................263
Congure Enhanced Transmission Selection..............................................................................................................264
Creating an ETS Priority Group..............................................................................................................................264
ETS Operation with DCBx......................................................................................................................................265
Conguring ETS in a DCB Map..............................................................................................................................265
Hierarchical Scheduling in ETS Output Policies......................................................................................................... 267
Using ETS to Manage Converged Ethernet Trac................................................................................................... 267
Applying DCB Policies in a Switch Stack.................................................................................................................... 267
Congure a DCBx Operation........................................................................................................................................ 267
DCBx Operation.......................................................................................................................................................268
DCBx Port Roles...................................................................................................................................................... 268
DCB Conguration Exchange................................................................................................................................ 269
Conguration Source Election................................................................................................................................270
Propagation of DCB Information............................................................................................................................270
Auto-Detection and Manual Conguration of the DCBx Version....................................................................... 271
DCBx Example.......................................................................................................................................................... 271
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