1DCB-ETS(8) Linux DCB-ETS(8)
2
6 dcb-app - show / manipulate application priority table of the DCB (Data
7 Center Bridging) subsystem
8
10 dcb [ OPTIONS ] app { COMMAND | help }
11 dcb app { show | flush } dev DEV [ default-prio ] [ ethtype-prio
14 ] [ stream-port-prio ] [ dgram-port-prio ] [ port-prio ] [
15 dscp-prio ] [ pcp-prio ]
16 dcb ets { add | del | replace } dev DEV [ default-prio PRIO-
18 LIST ] [ ethtype-prio ET-MAP ] [ stream-port-prio PORT-MAP ] [
19 dgram-port-prio PORT-MAP ] [ port-prio PORT-MAP ] [ dscp-prio
20 DSCP-MAP ] [ pcp-prio PCP-MAP ]
21 PRIO-LIST := [ PRIO-LIST ] PRIO
23 ET-MAP := [ ET-MAP ] ET-MAPPING
25 ET-MAPPING := ET:PRIO
27 PORT-MAP := [ PORT-MAP ] PORT-MAPPING
29 PORT-MAPPING := PORT:PRIO
31 DSCP-MAP := [ DSCP-MAP ] DSCP-MAPPING
33 DSCP-MAPPING := { DSCP | all }:PRIO
35 PCP-MAP := [ PCP-MAP ] PCP-MAPPING
37 PCP-MAPPING := PCP:PRIO
39 ET := { 0x600 .. 0xffff }
41 PORT := { 1 .. 65535 }
43 DSCP := { 0 .. 63 }
45 PCP := { 0(nd/de) .. 7(nd/de) }
47 PRIO := { 0 .. 7 }
49
52 dcb app is used to configure APP table, or application priority table
53 in the DCB (Data Center Bridging) subsystem. The APP table is used to
54 assign priority to traffic based on value in one of several headers:
55 EtherType, L4 destination port, or DSCP. It also allows configuration
56 of port-default priority that is chosen if no other prioritization rule
57 applies.
58 DCB APP entries are 3-tuples of selector, protocol ID, and priority.
60 Selector is an enumeration that picks one of the prioritization name‐
61 spaces. Currently it mostly corresponds to configurable parameters de‐
62 scribed below. Protocol ID is a value in the selector namespace. E.g.
63 for EtherType selector, protocol IDs are the individual EtherTypes, for
64 DSCP they are individual code points. The priority is the priority that
65 should be assigned to traffic that matches the selector and protocol
66 ID.
67 The APP table is a set of DCB APP entries. The only requirement is that
69 duplicate entries are not added. Notably, it is valid to have conflict‐
70 ing priority assignment for the same selector and protocol ID. For ex‐
71 ample, the set of two APP entries (DSCP, 10, 1) and (DSCP, 10, 2),
72 where packets with DSCP of 10 should get priority of both 1 and 2, form
73 a well-defined APP table. The dcb app tool allows low-level management
74 of the app table by adding and deleting individual APP 3-tuples through
75 add and del commands. On the other other hand, the command replace does
76 what one would typically want in this situation--first adds the new
77 configuration, and then removes the obsolete one, so that only one pri‐
78 oritization is in effect for a given selector and protocol ID.
79
82 show Display all entries with a given selector. When no selector is
83 given, shows all APP table entries categorized per selector.
84 flush Remove all entries with a given selector. When no selector is
87 given, removes all APP table entries.
88 add
91 del Add and, respectively, remove individual APP 3-tuples to and
92 from the DCB APP table.
93 replace
96 Take the list of entries mentioned as parameter, and add those
97 that are not present in the APP table yet. Then remove those en‐
98 tries, whose selector and protocol ID have been mentioned as pa‐
99 rameter, but not with the exact same priority. This has the ef‐
100 fect of, for the given selector and protocol ID, causing that
101 the table only contains the priority (or priorities) given as
102 parameter.
103
106 The following table shows parameters in a way that they would be used
107 with add, del and replace commands. For show and flush, the parameter
108 name is to be used as a simple keyword without further arguments.
109 default-prio PRIO-LIST
112 The priority to be used for traffic the priority of which is
113 otherwise unspecified. The argument is a list of individual pri‐
114 orities. Note that default-prio rules are configured as triplets
115 (EtherType, 0, PRIO). dcb app translates these rules to the
116 symbolic name default-prio and back.
117 ethtype-prio ET-MAP
120 ET-MAP uses the array parameter syntax, see dcb(8) for details.
121 Keys are EtherType values. Values are priorities to be assigned
122 to traffic with the matching EtherType.
123 stream-port-prio PORT-MAP
126 dgram-port-prio PORT-MAP
127 port-prio PORT-MAP
128 PORT-MAP uses the array parameter syntax, see dcb(8) for de‐
129 tails. Keys are L4 destination port numbers that match on, re‐
130 spectively, TCP and SCTP traffic, UDP and DCCP traffic, and ei‐
131 ther of those. Values are priorities that should be assigned to
132 matching traffic.
133 dscp-prio DSCP-MAP
136 DSCP-MAP uses the array parameter syntax, see dcb(8) for de‐
137 tails. Keys are DSCP points, values are priorities assigned to
138 traffic with matching DSCP. DSCP points can be written either
139 directly as numeric values, or using symbolic names specified in
140 /etc/iproute2/rt_dsfield (however note that that file specifies
141 full 8-bit dsfield values, whereas dcb app will only use the
142 higher six bits). dcb app show will similarly format DSCP val‐
143 ues as symbolic names if possible. The command line option -N
144 turns the show translation off.
145 pcp-prio PCP-MAP
148 PCP-MAP uses the array parameter syntax, see dcb(8) for details.
149 Keys are PCP/DEI. Values are priorities assigned to traffic with
150 matching PCP/DEI. PCP/DEI values are written as a combination of
151 numeric- and symbolic values, to accommodate for both. PCP al‐
152 ways in numerical form e.g 0 .. 7 and DEI in symbolic form e.g
153 'de' (drop-eligible), indicating that the DEI bit is 1 or 'nd'
154 (not-drop-eligible), indicating that the DEI bit is 0. In com‐
155 bination 2de:1 translates to a mapping of PCP=2 and DEI=1 to
156 priority 1.
157
160 Prioritize traffic with DSCP 0 to priority 0, 24 to 3 and 48 to 6:
161 # dcb app add dev eth0 dscp-prio 0:0 24:3 48:6
164 Add another rule to configure DSCP 24 to priority 2 and show the re‐
166 sult:
167 # dcb app add dev eth0 dscp-prio 24:2
170 # dcb app show dev eth0 dscp-prio
171 dscp-prio 0:0 CS3:2 CS3:3 CS6:6
172 # dcb -N app show dev eth0 dscp-prio
173 dscp-prio 0:0 24:2 24:3 48:6
174 Reconfigure the table so that the only rule for DSCP 24 is for assign‐
176 ment of priority 4:
177 # dcb app replace dev eth0 dscp-prio 24:4
180 # dcb app show dev eth0 dscp-prio
181 dscp-prio 0:0 24:4 48:6
182 Flush all DSCP rules:
184 # dcb app flush dev eth0 dscp-prio
187 # dcb app show dev eth0 dscp-prio
188 (nothing)
189 Add a rule to map traffic with PCP 1 and DEI 0 to priority 1 and PCP 2
191 and DEI 1 to priority 2:
192 # dcb app add dev eth0 pcp-prio 1nd:1 2de:2
195 # dcb app show dev eth0 pcp-prio
196 pcp-prio 1nd:1 2de:2
197
200 Exit status is 0 if command was successful or a positive integer upon
201 failure.
202
205 dcb(8)
206
209 Report any bugs to the Network Developers mailing list <net‐
210 dev@vger.kernel.org> where the development and maintenance is primarily
211 done. You do not have to be subscribed to the list to send a message
212 there.
213
216 Petr Machata <me@pmachata.org>
217iproute2 6 December 2020 DCB-ETS(8)