Owners Manual

Configure 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 DCB output
policy.
4. Apply the DCB output policy to an interface.
ETS Prerequisites and Restrictions
The following prerequisites and restrictions apply when you configure ETS bandwidth allocation or queue
scheduling and apply a DCB output policy on an interface.
• Configuring ETS bandwidth allocation or a queue scheduler for dot1p priorities in a priority group is
applicable if the DCBx version used on a port is CIN (refer to Configuring DCBx).
• When allocating bandwidth or configuring a queue scheduler for dot1p priorities in a priority group on
a DCBx CIN interface, take into account the CIN bandwidth allocation (refer to Configuring
Bandwidth Allocation for DCBx CIN) and dot1p-queue mapping.
• Although an DCB Output policy does not support WRED, ECN, rate shaping, and rate limiting because
DCBx does not negotiate these parameters with peer devices, you can apply a QoS output policy with
WRED and/or rate shaping on a DCBx CIN-enabled interface (refer to Configuring Port-Based Rate
Shaping and Weighted Random Early Detection). In this case, the WRED or rate shaping configuration
in the QoS output policy takes into account the bandwidth allocation or queue scheduler configured
in the DCB Output policy.
• You can only use a QoS DCB output policy in association with a priority group in a DCB output policy
and cannot be applied to an interface as a normal QoS output policy (refer to Applying an ETS Output
Policy for a Priority Group to an Interface and Creating an Output QoS Policy in the Quality of Service
(QoS) chapter.).
NOTE: The IEEE 802.1Qaz, CEE, and CIN versions of ETS are supported.
Data Center Bridging (DCB)
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