Administrator Guide

Traffic Groupings Description
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
– ETS shaping
– (Credit-based shaping is not supported)
• ETS uses the DCB MIB IEEE 802.1azd2.5.
Configuring Enhanced Transmission Selection
ETS provides a way to optimize bandwidth allocation to outbound 802.1p classes of converged Ethernet
traffic.
Different traffic types have different service needs. Using ETS, you can create groups within an 802.1p
priority class to configure different treatment for traffic with different bandwidth, latency, and best-effort
needs.
For example, storage traffic is sensitive to frame loss; interprocess communication (IPC) traffic is latency-
sensitive. ETS allows different traffic types to coexist without interruption in the same converged link by:
• Allocating a guaranteed share of bandwidth to each priority group.
• Allowing each group to exceed its minimum guaranteed bandwidth if another group is not fully using
its allotted bandwidth.
To configure ETS and apply an ETS output policy to an interface, you must:
1. Create a Quality of Service (QoS) output policy with ETS scheduling and bandwidth allocation
settings.
2. Create a priority group of 802.1p traffic classes.
3. Configure a DCB output policy in which you associate a priority group with a QoS ETS output policy.
Data Center Bridging (DCB)
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