Users Guide

Cos Rx Tx
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3 0 587236
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Supported Releases 10.3.0E or later
Enhanced transmission selection
ETS provides customized bandwidth allocation to 802.1p classes of trac. Assign dierent amounts of bandwidth to Ethernet, FCoE, or
iSCSI trac classes that require dierent bandwidth, latency, and best-eort treatment during network congestion.
ETS divides trac into dierent priority groups using their 802.1p priority value. To ensure that each trac class is correctly prioritized and
receives the required bandwidth, congure bandwidth and queue scheduling for each priority group. To prioritize low-latency storage and
server-cluster trac, allocate more bandwidth to a priority group. To rate-limit best-eort LAN trac, allocate less bandwidth to a dierent
priority group.
ETS conguration notes
• ETS is supported on Layer2 (L2) 802.1p priority (dot1p 0 to 7) and Layer 3 (L3) DSCP (0 to 63) trac. FCoE trac uses dot1p priority
3 — iSCSI storage trac uses dot1p priority 4.
• Apply these maps and policies on interfaces:
– Trust maps — OS10 interfaces do not honor the L2 and L3 priority elds in ingress trac by default. Create a trust map to honor
dot1p and DSCP classes of lossless trac. A trust map does not change ingress dot1p and DSCP values in egress ows. In a trust
map, assign a qos-group trac class to trusted dot1p/DSCP values. A qos-group number is used only internally to schedule
classes of ingress trac.
– QoS map — Create a QoS map to assign trusted dot1p and DSCP trac classes to lossless queues.
– Ingress trust policy — Congure a service policy to trust dot1p values in ingress trac.
– Egress queuing policy — Congure ETS for egress trac by assigning bandwidth to matching lossless queues in queuing class
and policy maps.
• Apply both PFC network-qos (input) and ETS queuing (output) policies on an interface to ensure lossless transmission.
• An ETS-enabled interface operates with dynamic weighted round robin (DWRR) or strict priority scheduling.
Converged data center services
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