lldptool
Section: Linux (8)
Updated: February 2010
Page Index
NAME
ETS-{CFG|REC} - Show / manipulate ETS TLV configuration
SYNOPSIS
lldptool -t -i ethx -V ETS-CFG
<-c
CONFIG_ARG
...>
CONFIG_ARG := {
enableTx | willing | tsa | up2tc | numtcs | tcbw }
CONFIG_ARG=value ...
CONFIG_ARG :=
enableTx = {yes|no} |
willing = {yes|no} |
tsa = tc:{ets|strict|vendor},... |
up2tc = priority:tc,... |
tcbw = bw1,bw2,...
<-c CONFIG_ARG ...>
CONFIG_ARG=value ...
CONFIG_ARG :=
enableTx = {yes|no} |
tsa = tc:{ets|strict|vendor},... |
up2tc = priority:tc,... |
tcbw = bw1,bw2,...
DESCRIPTION
The Enhanced Transmission Selection (ETS) feature has a recommendation
TLV and a configuration TLV configured with ETS-REC and ETS-CFG respectively.
ARGUMENTS
- enableTx
-
Enables the ETS TLV to be transmitted
- willing
-
Sets the ETS-CFG willing bit
- tsa
-
Transmission selection algorithm, sets a comma separated list of traffic classes to the corresponding selection algorithm. Valid algorithms include "ets", "strict" and "vendor".
- up2tc
-
Comma separated list mapping user priorities to traffic classes.
- tcbw
-
Comma separated list of bandwidths for each traffic class the first value
being assigned to traffic class 0 and the second to traffic class 1 and so
on. Undefined bandwidths are presumed to be 0.
- numtcs
-
Displays the number of ETS supported traffic classes.
Theory of Operations
IEEE 802.1Qaz is enabled by default on hardware that supports this mode
indicated by support for the DCBNL interface. Kernel config option
CONFIG_DCB. The ETS-CFG TLV is advertised by default with the attributes
indicated by querying the hardware for its current configuration. A
valid configuration is to map all priorities to a single traffic class
and use the link strict selection algorithm. This is equivalent to
being in a non-DCB enabled mode.
To support legacy DCBX (CIN or CEE) the ETS-CFG and ETS-REC TLVs are disabled
if a legacy DCBX TLV is received and no valid IEEE DCBX TLVs
are received. The hardware DCBX mode will also be set to the legacy
mode and IEEE mode is disabled. This allows switches to be configured and
end nodes will then be configured accordingly without any configuration
required on the end node. See lldpad(8) for more information
about the operation of the DCBX selection mechanism.
Mapping applications and protocols to traffic classes is required for
ETS to be useful. User space programs can encode the priority of an
application with the SO_PRIORITY option. The net_prio cgroup can be
used to assign application traffic to specific priorities. See the
kernel documentation and cgdcbxd(8) for net_prio cgroup information.
EXAMPLE & USAGE
- Configure willing bit for interface eth2
-
lldptool -T -i eth2 -V ETS-CFG willing=yes
- Configure traffic classes for ETS and strict priority on eth2
-
lldptool -T -i eth2 -V ETS-CFG tsa=0:ets,1:ets,2:ets,3:ets,4:strict,5:strict
- Configure 1:1 mapping from priority to traffic classes on eth2
-
lldptool -T -i eth2 -V ETS-CFG up2tc=0:0,1:1,2:2,3:3,4:4,5:5,6:6,7:7
- Display local configured ETS-CFG parameters for tcbw
-
lldptool -t -i eth2 -V ETS-CFG -c tcbw
- Display last transmitted ETS-CFG TLV
-
lldptool -t -i eth2 -V ETS-CFG
- Configure ETS-CFG and ETS-REC for default DCB on eth2
-
lldptool -T -i eth2 -V ETS-CFG tsa=0:ets,1:ets,2:ets,3:ets,4:ets,5:ets,6:ets,7:ets up2tc=0:0,1:1,2:2,3:3,4:4,5:5,6:6,7:7 tcbw=12,12,12,12,13,13,13,13
lldptool -T -i eth2 -V ETS-REC tsa=0:ets,1:ets,2:ets,3:ets,4:ets,5:ets,6:ets,7:ets up2tc=0:0,1:1,2:2,3:3,4:4,5:5,6:6,7:7 tcbw=12,12,12,12,13,13,13,13
SOURCE
- o
-
IEEE 802.1Qaz (http://www.ieee802.org/1/pages/dcbridges.html)
NOTES
Support for tc-mqprio was added in 2.6.38 on older kernels other mechanisms may need to be used to map applications to traffic classes.
SEE ALSO
lldptool(8),
lldptool-app(8),
lldpad(8),
tc-mqprio(8),
AUTHOR
John Fastabend