Users Guide

QoS OUTPUT POLICY mode
Dell(conf-qos-policy-out)#bandwidth-percentage 100
4. Exit QoS Output Policy Conguration mode.
QoS OUTPUT POLICY mode
Dell(conf-if-te-0/1)#exit
5. Enter INTERFACE Conguration mode.
CONFIGURATION mode
interface type slot/port
6. Apply the QoS output policy with the bandwidth percentage for specied priority queues to an egress interface.
INTERFACE mode
Dell(conf-if-te-0/1)#service-policy output test12
Conguring ETS in a DCB Map
An S4820T switch supports the use of a DCB map in which you congure enhanced transmission selection (ETS) setting. To
congure ETS parameters, you must apply a DCB map on an S4820T interface. This functionality is supported on the S4820T
platform.
ETS Conguration Notes
ETS provides a way to optimize bandwidth allocation to outbound 802.1p classes of converged Ethernet trac. Dierent trac types
have dierent service needs. Using ETS, you can create groups within an 802.1p priority class to congure dierent treatment for
tracs with dierent bandwidth, latency, and best-eort needs.
When you congure ETS in a DCB map:
• The DCB map associates a priority group with a PFC operational mode (on or o) and an ETS scheduling and bandwidth
allocation. You can apply a DCB map on multiple egress ports.
• Use the ETS conguration associated with 802.1p priority trac in a DCB map in DCBx negotiation with ETS peers.
• Trac in priority groups is assigned to strict-queue or weighted round-robin (WRR) scheduling in an ETS conguration and is
managed using the ETS bandwidth-assignment algorithm. Dell Networking OS de-queues all frames of strict-priority trac
before servicing any other queues. A queue with strict-priority trac can starve other queues in the same port.
• ETS-assigned bandwidth allocation and strict-priority scheduling apply only to data queues, not to control queues.
• Dell Networking OS supports hierarchical scheduling on an interface. The control trac on Dell Networking OS is redirected to
control queues as higher priority trac with strict priority scheduling. After the control queues drain out, the remaining data
trac is scheduled to queues according to the bandwidth and scheduler conguration in the DCB map. The available bandwidth
calculated by the ETS algorithm is equal to the link bandwidth after scheduling non-ETS higher-priority trac.
• The conguration of bandwidth allocation and strict-queue scheduling is not supported at the same time for a priority group.
• Bandwidth assignment: By default, equal bandwidth is assigned to each dot1p priority in a priority group. To congure the
bandwidth assigned to the port queues associated with dot1p priorities in a priority group, use the bandwidth percentage
parameter. The sum of the bandwidth allocated to all priority groups in a DCB map must be 100% of the bandwidth on the link.
You must allocate at least 1% of the total bandwidth to each priority group.
• Scheduling of priority trac: dot1p priority trac on the switch is scheduled to the current queue mapping. dot1p priorities
within the same queue must have the same trac properties and scheduling method.
• ETS conguration error: If an error occurs in an ETS conguration, the conguration is ignored and the scheduler and
bandwidth allocation settings are reset to the ETS default value: 100% of available bandwidth is allocated to priority group 0 and
the bandwidth is equally assigned to each dot1p priority.
If an error occurs when a port receives a peer’s ETS conguration, the port’s conguration resets to the ETS conguration in the
previously congured DCB map. If no DCB map was previously applied, the port resets to the default ETS parameters.
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Data Center Bridging (DCB)