Dell PowerEdge FX2/FX2s - Manual (Page 32)

Figure 2. Enhanced Transmission Selection
The following table lists the traffic groupings ETS uses to select multiprotocol traffic for transmission.
Table 2. ETS Traffic Groupings
Traffic Groupings Description
Priority group A group of 802.1p priorities used for bandwidth
allocation and queue scheduling. All 802.1p priority
traffic in a group must have the same traffic
handling requirements for latency and frame loss.
Group ID A 4-bit identifier assigned to each priority group.
The range is from 0 to 7.
Group bandwidth Percentage of available bandwidth allocated to a
priority group.
Group transmission selection algorithm (TSA) Type of queue scheduling a priority group uses.
In the Dell Networking OS, ETS is implemented as follows:
• ETS supports groups of 802.1p priorities that have:
– PFC enabled or disabled
– No bandwidth limit or no ETS processing
• Bandwidth allocated by the ETS algorithm is made available after strict-priority groups are serviced. If
a priority group does not use its allocated bandwidth, the unused bandwidth is made available to
other priority groups so that the sum of the bandwidth use is 100%. If priority group bandwidth use
exceeds 100%, all configured priority group bandwidth is decremented based on the configured
percentage ratio until all priority group bandwidth use is 100%. If priority group bandwidth usage is
less than or equal to 100% and any default priority groups exist, a minimum of 1% bandwidth use is
assigned by decreasing 1% of bandwidth from the other priority groups until priority group bandwidth
use is 100%.
• For ETS traffic selection, an algorithm is applied to priority groups using:
– Strict priority shaping
32 Data Center Bridging (DCB)