OPENFLOW-1.1+.md

   1 OpenFlow 1.1+ support in Open vSwitch
   2 =====================================
   3
   4 Open vSwitch support for OpenFlow 1.1 and beyond is a work in
   5 progress.  This file describes the work still to be done.
   6
   7 The Plan
   8 --------
   9
  10 OpenFlow version support is not a build-time option.  A single build
  11 of Open vSwitch must be able to handle all supported versions of
  12 OpenFlow.  Ideally, even at runtime it should be able to support all
  13 protocol versions at the same time on different OpenFlow bridges (and
  14 perhaps even on the same bridge).
  15
  16 At the same time, it would be a shame to litter the core of the OVS
  17 code with lots of ugly code concerned with the details of various
  18 OpenFlow protocol versions.
  19
  20 The primary approach to compatibility is to abstract most of the
  21 details of the differences from the core code, by adding a protocol
  22 layer that translates between OF1.x and a slightly higher-level
  23 abstract representation.  The core of this approach is the many struct
  24 ofputil_* structures in lib/ofp-util.h.
  25
  26 As a consequence of this approach, OVS cannot use OpenFlow protocol
  27 definitions that closely resemble those in the OpenFlow specification,
  28 because openflow.h in different versions of the OpenFlow specification
  29 defines the same identifier with different values.  Instead,
  30 openflow-common.h contains definitions that are common to all the
  31 specifications and separate protocol version-specific headers contain
  32 protocol-specific definitions renamed so as not to conflict,
  33 e.g. OFPAT10_ENQUEUE and OFPAT11_ENQUEUE for the OpenFlow 1.0 and 1.1
  34 values for OFPAT_ENQUEUE.  Generally, in cases of conflict, the
  35 protocol layer will define a more abstract OFPUTIL_* or struct
  36 ofputil_*.
  37
  38 Here are the current approaches in a few tricky areas:
  39
  40   * Port numbering.  OpenFlow 1.0 has 16-bit port numbers and later
  41     OpenFlow versions have 32-bit port numbers.  For now, OVS
  42     support for later protocol versions requires all port numbers to
  43     fall into the 16-bit range, translating the reserved OFPP_* port
  44     numbers.
  45
  46   * Actions.  OpenFlow 1.0 and later versions have very different
  47     ideas of actions.  OVS reconciles by translating all the
  48     versions' actions (and instructions) to and from a common
  49     internal representation.
  50
  51 OpenFlow 1.1
  52 ------------
  53
  54 The list of remaining work items for OpenFlow 1.1 is below.  It is
  55 probably incomplete.
  56
  57   * Match and set double-tagged VLANs (QinQ).  This requires kernel
  58     work for reasonable performance.
  59     [optional for OF1.1+]
  60
  61   * VLANs tagged with 88a8 Ethertype.  This requires kernel work for
  62     reasonable performance.
  63     [required for OF1.1+]
  64
  65 OpenFlow 1.2
  66 ------------
  67
  68 OpenFlow 1.2 support requires OpenFlow 1.1 as a prerequisite. All the
  69 additional work specific to Openflow 1.2 are complete.  (This is based
  70 on the change log at the end of the OF1.2 spec.  I didn't compare the
  71 specs carefully yet.)
  72
  73 OpenFlow 1.3
  74 ------------
  75
  76 OpenFlow 1.3 support requires OpenFlow 1.2 as a prerequisite, plus the
  77 following additional work.  (This is based on the change log at the
  78 end of the OF1.3 spec, reusing most of the section titles directly.  I
  79 didn't compare the specs carefully yet.)
  80
  81   * Add support for multipart requests.
  82     Currently we always report OFPBRC_MULTIPART_BUFFER_OVERFLOW.
  83     [optional for OF1.3+]
  84
  85   * IPv6 extension header handling support.  Fully implementing this
  86     requires kernel support.  This likely will take some careful and
  87     probably time-consuming design work.  The actual coding, once
  88     that is all done, is probably 2 or 3 days work.
  89     [optional for OF1.3+]
  90
  91   * Per-flow meters.  OpenFlow protocol support is now implemented.
  92     Support for the special OFPM_SLOWPATH and OFPM_CONTROLLER meters
  93     is missing.  Support for the software switch is under review.
  94     [optional for OF1.3+]
  95
  96   * Auxiliary connections.  An implementation in generic code might
  97     be a week's worth of work.  The value of an implementation in
  98     generic code is questionable, though, since much of the benefit
  99     of axuiliary connections is supposed to be to take advantage of
 100     hardware support.  (We could make the kernel module somehow
 101     send packets across the auxiliary connections directly, for
 102     some kind of "hardware" support, if we judged it useful enough.)
 103     [optional for OF1.3+]
 104
 105   * Provider Backbone Bridge tagging.  I don't plan to implement
 106     this (but we'd accept an implementation).
 107     [optional for OF1.3+]
 108
 109   * On-demand flow counters.  I think this might be a real
 110     optimization in some cases for the software switch.
 111     [optional for OF1.3+]
 112
 113 OpenFlow 1.4 & ONF Extensions for 1.3.X Pack1
 114 ---------------------------------------------
 115
 116 The following features are both defined as a set of ONF Extensions
 117 for 1.3 and integrated in 1.4.
 118 When defined as an ONF Extension for 1.3, the feature is using the
 119 Experimenter mechanism with the ONF Experimenter ID.
 120 When defined integrated in 1.4, the feature use the standard OpenFlow
 121 structures (for example defined in openflow-1.4.h).
 122 The two definitions for each feature are independant and can exist in
 123 parallel in OVS.
 124
 125   * Flow entry notifications
 126     This seems to be modelled after OVS's NXST_FLOW_MONITOR.
 127     (Simon Horman is working on this.)
 128     [EXT-187]
 129     [optional for OF1.4+]
 130
 131   * Role Status
 132     Already implemented as a 1.4 feature.
 133     [EXT-191]
 134     [required for OF1.4+]
 135
 136   * Flow entry eviction
 137     OVS has flow eviction functionality.
 138     table_mod OFPTC_EVICTION, flow_mod 'importance', and
 139     table_desc ofp_table_mod_prop_eviction need to be implemented.
 140     [EXT-192-e]
 141     [optional for OF1.4+]
 142
 143   * Vacancy events
 144     [EXT-192-v]
 145     [optional for OF1.4+]
 146
 147   * Bundle
 148     Transactional modification.  OpenFlow 1.4 requires to support
 149     flow_mods and port_mods in a bundle if bundle is supported.
 150     (Not related to OVS's 'ofbundle' stuff.)
 151     Implemented as an OpenFlow 1.4 feature.  Only flow_mods and
 152     port_mods are supported in a bundle.  If the bundle includes port
 153     mods, it may not specify the OFPBF_ATOMIC flag.  Nevertheless,
 154     port mods and flow mods in a bundle are always applied in order
 155     and consecutive flow mods between port mods are made available to
 156     lookups atomically.
 157     [EXT-230]
 158     [optional for OF1.4+]
 159
 160   * Table synchronisation
 161     Probably not so useful to the software switch.
 162     [EXT-232]
 163     [optional for OF1.4+]
 164
 165   * Group and Meter change notifications
 166     [EXT-235]
 167     [optional for OF1.4+]
 168
 169   * Bad flow entry priority error
 170     Probably not so useful to the software switch.
 171     [EXT-236]
 172     [optional for OF1.4+]
 173
 174   * Set async config error
 175     [EXT-237]
 176     [optional for OF1.4+]
 177
 178   * PBB UCA header field
 179     See comment on Provider Backbone Bridge in section about OpenFlow 1.3.
 180     [EXT-256]
 181     [optional for OF1.4+]
 182
 183   * Multipart timeout error
 184     [EXT-264]
 185     [required for OF1.4+]
 186
 187 OpenFlow 1.4 only
 188 -----------------
 189
 190 Those features are those only available in OpenFlow 1.4, other
 191 OpenFlow 1.4 features are listed in the previous section.
 192
 193   * More extensible wire protocol
 194     Many on-wire structures got TLVs.
 195     Already implemented: port desc properties, port mod properties,
 196                          port stats properties, table mod properties,
 197                          queue stats, unified property errors, queue desc.
 198     Remaining required: set-async
 199     Remaining optional: table desc, table-status
 200     [EXT-262]
 201     [required for OF1.4+]
 202
 203   * More descriptive reasons for packet-in
 204     Distinguish OFPR_APPLY_ACTION, OFPR_ACTION_SET, OFPR_GROUP,
 205     OFPR_PACKET_OUT.  NO_MATCH was renamed to OFPR_TABLE_MISS.
 206     (OFPR_ACTION_SET and OFPR_GROUP are now supported)
 207     [EXT-136]
 208     [required for OF1.4+]
 209
 210   * Optical port properties
 211     [EXT-154]
 212     [optional for OF1.4+]
 213
 214 OpenFlow 1.5 & ONF Extensions for 1.3.X Pack2
 215 ---------------------------------------------
 216
 217 The following features are both defined as a set of ONF Extensions for
 218 1.3 and integrated in 1.5. Note that this list is not definitive as
 219 those are not yet published.
 220 When defined as an ONF Extension for 1.3, the feature is using the
 221 Experimenter mechanism with the ONF Experimenter ID.
 222 When defined integrated in 1.5, the feature use the standard OpenFlow
 223 structures (for example defined in openflow-1.5.h).
 224 The two definitions for each feature are independant and can exist in
 225 parallel in OVS.
 226
 227   * Time scheduled bundles
 228     [EXT-340]
 229     [optional for OF1.5+]
 230
 231 OpenFlow 1.5 only
 232 -----------------
 233
 234 Those features are those only available in OpenFlow 1.5, other
 235 OpenFlow 1.5 features are listed in the previous section.
 236 Note that this list is not definitive as OpenFlow 1.5 is not yet
 237 published.
 238
 239   * Egress Tables
 240     [EXT-306]
 241     [optional for OF1.5+]
 242
 243   * Packet Type aware pipeline
 244     Prototype for OVS was done during specification.
 245     [EXT-112]
 246     [optional for OF1.5+]
 247
 248   * Extensible Flow Entry Statistics
 249     [EXT-334]
 250     [required for OF1.5+]
 251
 252   * Flow Entry Statistics Trigger
 253     [EXT-335]
 254     [optional for OF1.5+]
 255
 256   * Controller connection status
 257     Prototype for OVS was done during specification.
 258     [EXT-454]
 259     [optional for OF1.5+]
 260
 261   * Meter action
 262     [EXT-379]
 263     [required for OF1.5+ if metering is supported]
 264
 265   * Enable setting all pipeline fields in packet-out
 266     Prototype for OVS was done during specification.
 267     [EXT-427]
 268     [required for OF1.5+]
 269
 270   * Port properties for pipeline fields
 271     Prototype for OVS was done during specification.
 272     [EXT-388]
 273     [optional for OF1.5+]
 274
 275   * Port property for recirculation
 276     Prototype for OVS was done during specification.
 277     [EXT-399]
 278     [optional for OF1.5+]
 279
 280 General
 281 -----
 282
 283   * ovs-ofctl(8) often lists as Nicira extensions features that
 284     later OpenFlow versions support in standard ways.
 285
 286 How to contribute
 287 -----------------
 288
 289 If you plan to contribute code for a feature, please let everyone know
 290 on ovs-dev before you start work.  This will help avoid duplicating
 291 work.
 292
 293 Please consider the following:
 294
 295   * Testing.  Please test your code.
 296
 297   * Unit tests.  Please consider writing some.  The tests directory
 298     has many examples that you can use as a starting point.
 299
 300   * ovs-ofctl.  If you add a feature that is useful for some
 301     ovs-ofctl command then you should add support for it there.
 302
 303   * Documentation.  If you add a user-visible feature, then you
 304     should document it in the appropriate manpage and mention it in
 305     NEWS as well.
 306
 307   * Coding style (see the [CodingStyle.md] file at the top of the
 308     source tree).
 309
 310   * The patch submission guidelines (see [CONTRIBUTING.md]).  I
 311     recommend using "git send-email", which automatically follows a
 312     lot of those guidelines.
 313
 314 Bug Reporting
 315 -------------
 316
 317 Please report problems to bugs@openvswitch.org.
 318
 319 [CONTRIBUTING.md]:CONTRIBUTING.md
 320 [CodingStyle.md]:CodingStyle.md