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 ]
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 ]
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 ET := { 0x600 .. 0xffff }
37 PORT := { 1 .. 65535 }
39 DSCP := { 0 .. 63 }
41 PRIO := { 0 .. 7 }
43
46 dcb app is used to configure APP table, or application priority table
47 in the DCB (Data Center Bridging) subsystem. The APP table is used to
48 assign priority to traffic based on value in one of several headers:
49 EtherType, L4 destination port, or DSCP. It also allows configuration
50 of port-default priority that is chosen if no other prioritization rule
51 applies.
52 DCB APP entries are 3-tuples of selector, protocol ID, and priority.
54 Selector is an enumeration that picks one of the prioritization name‐
55 spaces. Currently it mostly corresponds to configurable parameters de‐
56 scribed below. Protocol ID is a value in the selector namespace. E.g.
57 for EtherType selector, protocol IDs are the individual EtherTypes, for
58 DSCP they are individual code points. The priority is the priority that
59 should be assigned to traffic that matches the selector and protocol
60 ID.
61 The APP table is a set of DCB APP entries. The only requirement is that
63 duplicate entries are not added. Notably, it is valid to have conflict‐
64 ing priority assignment for the same selector and protocol ID. For ex‐
65 ample, the set of two APP entries (DSCP, 10, 1) and (DSCP, 10, 2),
66 where packets with DSCP of 10 should get priority of both 1 and 2, form
67 a well-defined APP table. The dcb app tool allows low-level management
68 of the app table by adding and deleting individual APP 3-tuples through
69 add and del commands. On the other other hand, the command replace does
70 what one would typically want in this situation--first adds the new
71 configuration, and then removes the obsolete one, so that only one pri‐
72 oritization is in effect for a given selector and protocol ID.
73
76 show Display all entries with a given selector. When no selector is
77 given, shows all APP table entries categorized per selector.
78 flush Remove all entries with a given selector. When no selector is
81 given, removes all APP table entries.
82 add
85 del Add and, respectively, remove individual APP 3-tuples to and
86 from the DCB APP table.
87 replace
90 Take the list of entries mentioned as parameter, and add those
91 that are not present in the APP table yet. Then remove those en‐
92 tries, whose selector and protocol ID have been mentioned as pa‐
93 rameter, but not with the exact same priority. This has the ef‐
94 fect of, for the given selector and protocol ID, causing that
95 the table only contains the priority (or priorities) given as
96 parameter.
97
100 The following table shows parameters in a way that they would be used
101 with add, del and replace commands. For show and flush, the parameter
102 name is to be used as a simple keyword without further arguments.
103 default-prio PRIO-LIST
106 The priority to be used for traffic the priority of which is
107 otherwise unspecified. The argument is a list of individual pri‐
108 orities. Note that default-prio rules are configured as triplets
109 (EtherType, 0, PRIO). dcb app translates these rules to the
110 symbolic name default-prio and back.
111 ethtype-prio ET-MAP
114 ET-MAP uses the array parameter syntax, see dcb(8) for details.
115 Keys are EtherType values. Values are priorities to be assigned
116 to traffic with the matching EtherType.
117 stream-port-prio PORT-MAP
120 dgram-port-prio PORT-MAP
121 port-prio PORT-MAP
122 PORT-MAP uses the array parameter syntax, see dcb(8) for de‐
123 tails. Keys are L4 destination port numbers that match on, re‐
124 spectively, TCP and SCTP traffic, UDP and DCCP traffic, and ei‐
125 ther of those. Values are priorities that should be assigned to
126 matching traffic.
127 dscp-prio DSCP-MAP
130 DSCP-MAP uses the array parameter syntax, see dcb(8) for de‐
131 tails. Keys are DSCP points, values are priorities assigned to
132 traffic with matching DSCP. DSCP points can be written either
133 directly as numeric values, or using symbolic names specified in
134 /etc/iproute2/rt_dsfield (however note that that file specifies
135 full 8-bit dsfield values, whereas dcb app will only use the
136 higher six bits). dcb app show will similarly format DSCP val‐
137 ues as symbolic names if possible. The command line option -N
138 turns the show translation off.
139
142 Prioritize traffic with DSCP 0 to priority 0, 24 to 3 and 48 to 6:
143 # dcb app add dev eth0 dscp-prio 0:0 24:3 48:6
146 Add another rule to configure DSCP 24 to priority 2 and show the re‐
148 sult:
149 # dcb app add dev eth0 dscp-prio 24:2
152 # dcb app show dev eth0 dscp-prio
153 dscp-prio 0:0 CS3:2 CS3:3 CS6:6
154 # dcb -N app show dev eth0 dscp-prio
155 dscp-prio 0:0 24:2 24:3 48:6
156 Reconfigure the table so that the only rule for DSCP 24 is for assign‐
158 ment of priority 4:
159 # dcb app replace dev eth0 dscp-prio 24:4
162 # dcb app show dev eth0 dscp-prio
163 dscp-prio 0:0 24:4 48:6
164 Flush all DSCP rules:
166 # dcb app flush dev eth0 dscp-prio
169 # dcb app show dev eth0 dscp-prio
170 (nothing)
171
174 Exit status is 0 if command was successful or a positive integer upon
175 failure.
176
179 dcb(8)
180
183 Report any bugs to the Network Developers mailing list <net‐
184 dev@vger.kernel.org> where the development and maintenance is primarily
185 done. You do not have to be subscribed to the list to send a message
186 there.
187
190 Petr Machata <me@pmachata.org>
191iproute2 6 December 2020 DCB-ETS(8)