Enhanced Transmission Selection - Dell Force10 S4810P Configuration Manual

High-density, 1ru 48-port 10gbe switch

Hide thumbs Also See for Force10 S4810P:

Table of Contents

Enhanced Transmission Selection

Enhanced transmission selection (ETS) supports optimized bandwidth allocation between traffic types in

multiprotocol (Ethernet, FCoE, SCSI) links. ETS allows you to divide traffic according to its 802.1p

priority into different priority groups (traffic classes) and configure bandwidth allocation and queue

scheduling for each group to ensure that each traffic type is correctly prioritized and receives its required

bandwidth. For example, you can prioritize low-latency storage or server cluster traffic in a traffic class to

receive more bandwidth and restrict best-effort LAN traffic assigned to a different traffic class.

Although you can configure strict-priority queue scheduling for a priority group, ETS introduces flexibility

that allows the bandwidth allocated to each priority group to be dynamically managed according to the

amount of LAN, storage, and server traffic in a flow. Unused bandwidth is dynamically allocated to

prioritized priority groups. Traffic is queued according to its 802.1p priority assignment, while flexible

bandwidth allocation and the configured queue-scheduling for a priority group is supported.

according to 802.1p priority and mapped to priority groups.

Figure 13-2. Enhanced Transmission Selection

ETS uses the following traffic groupings to select multiprotocol traffic for transmission:

Priority group: A group of 802.1p priorities used for bandwidth allocation and queue scheduling. All

802.1p priority traffic in a group should have the same traffic handling requirements for latency and

Group ID: A 4-bit identifier assigned to each priority group. 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 used by a priority group.

ETS is implemented as follows in FTOS:

ETS supports groups of 802.1p priorities that have:

PFC enabled or disabled

No bandwidth limit or no ETS processing

Data Center Bridging (DCB)

shows how ETS allows you to allocate bandwidth when different traffic types are classed