DCB-ETS(8) Linux DCB-ETS(8)
NAME
dcb-ets - show / manipulate ETS (Enhanced Transmission Selection) set-
tings of the DCB (Data Center Bridging) subsystem
SYNOPSIS
dcb [ OPTIONS ] ets { COMMAND | help }
dcb ets show dev DEV [ willing ] [ ets-cap ] [ cbs ] [ tc-tsa ] [ reco-
tc-tsa ] [ pg-bw ] [ tc-bw ] [ reco-tc-bw ] [ prio-tc ] [ reco-
prio-tc ]
dcb ets set dev DEV [ willing { on | off } ] [ { tc-tsa | reco-tc-tsa }
TSA-MAP ] [ { pg-bw | tc-bw | reco-tc-bw } BW-MAP ] [ { prio-tc
| reco-prio-tc } PRIO-MAP ]
TSA-MAP := [ TSA-MAP ] TSA-MAPPING
TSA-MAPPING := { TC | all }:{ strict | cbs | ets | vendor }
BW-MAP := [ BW-MAP ] BW-MAPPING
BW-MAPPING := { TC | all }:INTEGER
PRIO-MAP := [ PRIO-MAP ] PRIO-MAPPING
PRIO-MAPPING := { PRIO | all }:TC
TC := { 0 .. 7 }
PRIO := { 0 .. 7 }
DESCRIPTION
dcb ets is used to configure Enhanced Transmission Selection attributes
through Linux DCB (Data Center Bridging) interface. ETS permits config-
uration of mapping of priorities to traffic classes, traffic selection
algorithm to use per traffic class, bandwidth allocation, etc.
Two DCB TLVs are related to the ETS feature: a configuration and recom-
mendation values. Recommendation values are named with a prefix reco-,
while the configuration ones have plain names.
PARAMETERS
For read-write parameters, the following describes only the write di-
rection, i.e. as used with the set command. For the show command, the
parameter name is to be used as a simple keyword without further argu-
ments. This instructs the tool to show the value of a given parameter.
When no parameters are given, the tool shows the complete ETS configu-
ration.
ets-cap
A read-only property that shows the number of supported ETS
traffic classes.
cbs A read-only property that is enabled if the driver and the hard-
ware support the CBS Transmission Selection Algorithm.
willing { on | off }
Whether local host should accept configuration from peer TLVs.
prio-tc PRIO-MAP
reco-prio-tc PRIO-MAP
PRIO-MAP uses the array parameter syntax, see dcb(8) for de-
tails. Keys are priorities, values are traffic classes. For each
priority sets a TC where traffic with that priority is directed
to.
tc-tsa TSA-MAP
reco-tc-tsa TSA-MAP
TSA-MAP uses the array parameter syntax, see dcb(8) for details.
Keys are TCs, values are Transmission Selection Algorithm (TSA)
keywords described below. For each TC sets an algorithm used for
deciding how traffic queued up at this TC is scheduled for
transmission. Supported TSAs are:
strict - for strict priority, where traffic in higher-numbered
TCs always takes precedence over traffic in lower-numbered TCs.
ets - for Enhanced Traffic Selection, where available bandwidth
is distributed among the ETS-enabled TCs according to the
weights set by tc-bw and reco-tc-bw, respectively.
cbs - for Credit Based Shaper, where traffic is scheduled in a
strict manner up to the limit set by a shaper.
vendor - for vendor-specific traffic selection algorithm.
tc-bw BW-MAP
reco-tc-bw BW-MAP
BW-MAP uses the array parameter syntax, see dcb(8) for details.
Keys are TCs, values are integers representing percent of avail-
able bandwidth given to the traffic class in question. The value
should be 0 for TCs whose TSA is not ets, and the sum of all
values shall be 100. As an exception to the standard wording, a
configuration with no ets TCs is permitted to sum up to 0 in-
stead.
pg-bw BW-MAP
The precise meaning of pg-bw is not standardized, but the as-
sumption seems to be that the same scheduling process as on the
transmit side is applicable on receive side as well, and config-
ures receive bandwidth allocation for ets ingress traffic
classes (priority groups).
EXAMPLE & USAGE
Configure ETS priomap in a one-to-one fashion:
# dcb ets set dev eth0 prio-tc 0:0 1:1 2:2 3:3 4:4 5:5 6:6 7:7
Set TSA and transmit bandwidth configuration:
# dcb ets set dev eth0 tc-tsa all:strict 0:ets 1:ets 2:ets \
tc-bw all:0 0:33 1:33 2:34
Show what was set:
# dcb ets show dev eth0 prio-tc tc-tsa tc-bw
prio-tc 0:0 1:1 2:2 3:3 4:4 5:5 6:6 7:7
tc-tsa 0:ets 1:ets 2:ets 3:strict 4:strict 5:strict 6:strict 7:strict
tc-bw 0:33 1:33 2:34 3:0 4:0 5:0 6:0 7:0
EXIT STATUS
Exit status is 0 if command was successful or a positive integer upon
failure.
SEE ALSO
dcb(8)
REPORTING BUGS
Report any bugs to the Network Developers mailing list <net-
dev@vger.kernel.org> where the development and maintenance is primarily
done. You do not have to be subscribed to the list to send a message
there.
AUTHOR
Petr Machata <me@pmachata.org>
iproute2 19 October 2020 DCB-ETS(8)
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