Reference Guide

DCB provides lossless transmission of FCoE and iSCSI storage trac using:
• Separate trac classes for the dierent service needs of network applications.
• PFC ow control to pause data transmission and avoid dropping packets during congestion.
• ETS bandwidth allocation to guarantee a percentage of shared bandwidth to bursty trac, while allowing each trac class to exceed
its allocated bandwidth if another trac class is not using its share.
• DCBX discovery of peers, including parameter exchange (PFC, ETS, and other DCB settings), mismatch detection, and remote
conguration of DCB parameters.
• iSCSI application protocol TLV information in DCBX advertisements to communicate iSCSI support to peer ports
This example shows how to congure a sample DCB converged network in which:
• DCBx is enabled globally to ensure the exchange of DCBx, PFC, ETS, and ISCSI congurations between DCBx-enabled devices.
• PFC is congured to ensure loseless trac for dot1p priority 4, 5, 6, and 7 trac.
• ETS allocates 30% bandwidth for dot1p priority 0, 1, 2, and 3 trac and 70% bandwidth for priority 4, 5, 6, and 7 trac.
• iSCSI is congured to use dot1p priority 6 for iSCSI trac, and advertise priority 6 in iSCSI application TLVs.
• The default class-trust class map honors dot1p priorities in ingress ows and applies a 1-to-1 dot1p-to-qos-group and a 1-to-1 qos-
group-to-queue mapping. In OS10, qos-group represents a trac class used only for internal processing.
1. DCBX conguration (global)
Congure DCBX globally on a switch to enable the exchange of DCBX TLV messages with PFC, ETS, and iSCSI congurations.
OS10# configure terminal
OS10(config)# dcbx enable
2. PFC conguration (global)
PFC is enabled on trac classes with dot1p 4, 5, 6, and 7 trac. The trac classes all use the default PFC pause settings for shared buer
size and pause frames in ingress queue processing in the network-qos policy map. The pclass policy map honors (trusts) all dot1p ingress
trac. The reserved class-trust class map is congured by default. Trust does not modify ingress values in output ows.
OS10(config)# class-map type network-qos test4
OS10(config-cmap-nqos)# match qos-group 4
OS10(config-cmap-nqos)# exit
OS10(config)# class-map type network-qos test5
OS10(config-cmap-nqos)# match qos-group 5
OS10(config-cmap-nqos)# exit
OS10(config)# class-map type network-qos test6
OS10(config-cmap-nqos)# match qos-group 6
OS10(config-cmap-nqos)# exit
OS10(config)# class-map type network-qos test7
OS10(config-cmap-nqos)# match qos-group 7
OS10(config-cmap-nqos)# exit
OS10(config)# policy-map type network-qos test
OS10(config-pmap-network-qos)# class test4
OS10(config-pmap-c-nqos)# pause
OS10(config-pmap-c-nqos)# pfc-cos 4
OS10(config-pmap-c-nqos)# exit
OS10(config-pmap-network-qos)# class test5
OS10(config-pmap-c-nqos)# pause
OS10(config-pmap-c-nqos)# pfc-cos 5
OS10(config-pmap-c-nqos)# exit
OS10(config-pmap-network-qos)# class test6
OS10(config-pmap-c-nqos)# pause
OS10(config-pmap-c-nqos)# pfc-cos 6
OS10(config-pmap-c-nqos)# exit
OS10(config-pmap-network-qos)# class test7
OS10(config-pmap-c-nqos)# pause
OS10(config-pmap-c-nqos)# pfc-cos 7
OS10(config-pmap-c-nqos)# exit
OS10(config-pmap-network-qos)# exit
Converged data center services
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