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BP1037 Transitioning to DCB with EqualLogic PS series Storage Solutions 14
4 Transitioning to DCB
4.1 Classes of DCB switches
DCB capable switches can be categorized into different classes. “Core DCB” switches, “Bridge DCB”
switches and “non-DCB” switches. Figure 6 illustrates the relationship of these different switch classes
when used together to provide a transitional DCB datacenter environment.
Figure 6 DCB switch classes
4.1.1 Core DCB switch
DCB “core” switches must have full DCB feature support, as specified in section 2.3. In order to
achieve full DCB support, a core switch must be capable of supporting the full set of DCB standards.
As a core DCB switch, this type of switch is expected to manage multiple, disparate streams of
Ethernet traffic. To be able to provide this service, this class of switch must be able to manage flow
control (through PFC), bandwidth guarantees for specific types of traffic (through ETS), and optionally
congestion awareness (through Congestion Notification). In addition, it must be able to apply these
controls across all types of traffic streams including those based on application TLVs like iSCSI.
4.1.2 Bridge DCB switch
“Bridge” DCB switches are switches that have, at a minimum, support for PFC, but may not support all
features of DCB. These switches can be introduced as gateway, or bridge switches that work with the
core DCB switches to achieve DCB functionality, without disrupting the existing network architecture
containing non-DCB switches. In this role, these bridge switches manage only a single type of traffic–
much like a non-DCB switch, but have the ability to honor upstream DCB management as it forwards
and receives traffic from core DCB switches that are assigned to the specific devices directly attached