Enhanced Transmission Selection - Dell S6000–ON Configuration Manual

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By default, PFC is enabled when you enable DCB. If you have not loaded FCoE_DCB_Config and

iSCSI_DCB_Config, DCB is disabled. When you enable DCB globally, you cannot simultaneously

enable link-level flow control.

Buffer space is allocated and de-allocated only when you configure a PFC priority on the port.

Enhanced Transmission Selection

Enhanced transmission selection (ETS) supports optimized bandwidth allocation between traffic types in

multiprotocol (Ethernet, FCoE, SCSI) links.

ETS allows you to divide traffic according to its 802.1p priority into different priority groups (traffic

classes) and configure bandwidth allocation and queue scheduling for each group to ensure that each

traffic type is correctly prioritized and receives its required bandwidth. For example, you can prioritize

low-latency storage or server cluster traffic in a traffic class to receive more bandwidth and restrict best-

effort LAN traffic assigned to a different traffic class.

The following figure shows how ETS allows you to allocate bandwidth when different traffic types are

classed according to 802.1p priority and mapped to priority groups.

Figure 29. Enhanced Transmission Selection

The following table lists the traffic groupings ETS uses to select multiprotocol traffic for transmission.

Table 13. ETS Traffic Groupings

Traffic Groupings

Group bandwidth

Group transmission selection algorithm (TSA)

In Dell Networking OS, ETS is implemented as follows:

ETS supports groups of 802.1p priorities that have:

A 4-bit identifier assigned to each priority group.

The range is from 0 to 7 configurable; 8 - 14

reservation and 15.0 - 15.7 is strict priority group..

Percentage of available bandwidth allocated to a

priority group.

Type of queue scheduling a priority group uses.

Data Center Bridging (DCB)