OPENFLOW-1.1+

   1                 OpenFlow 1.1+ support in Open vSwitch
   2                 =====================================
   3
   4 Open vSwitch support for OpenFlow 1.1, 1.2, and 1.3 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     * OFPT_TABLE_MOD message.  This is new in OF1.1, so we need to
  58       implement it.  It should be implemented so that the default OVS
  59       behavior does not change.
  60       [required for OF1.1 and OF1.2]
  61
  62     * MPLS.  Simon Horman maintains a patch series that adds this
  63       feature.  This is partially merged.
  64       [optional for OF1.1+]
  65
  66     * Match and set double-tagged VLANs (QinQ).  This requires kernel
  67       work for reasonable performance.
  68       [optional for OF1.1+]
  69
  70     * VLANs tagged with 88a8 Ethertype.  This requires kernel work for
  71       reasonable performance.
  72       [required for OF1.1+]
  73
  74 OpenFlow 1.2
  75 ------------
  76
  77 OpenFlow 1.2 support requires OpenFlow 1.1 as a prerequisite. All the
  78 additional work specific to Openflow 1.2 are complete.  (This is based
  79 on the change log at the end of the OF1.2 spec.  I didn't compare the
  80 specs carefully yet.)
  81
  82 OpenFlow 1.3
  83 ------------
  84
  85 OpenFlow 1.3 support requires OpenFlow 1.2 as a prerequisite, plus the
  86 following additional work.  (This is based on the change log at the
  87 end of the OF1.3 spec, reusing most of the section titles directly.  I
  88 didn't compare the specs carefully yet.)
  89
  90     * Add support for multipart requests.
  91       Currently we always report OFPBRC_MULTIPART_BUFFER_OVERFLOW.
  92       [optional for OF1.3+]
  93
  94     * Add OFPMP_TABLE_FEATURES statistics.
  95       [optional for OF1.3+]
  96
  97     * More flexible table miss support.
  98       This requires the following.
  99       - Change the default table-miss action (in the absense of table-miss
 100         entry) from packet_in to drop for OF1.3+.  Decide what to do if
 101         a switch is configured to support multiple OF versions.
 102       [required for OF1.3+]
 103
 104     * IPv6 extension header handling support.  Fully implementing this
 105       requires kernel support.  This likely will take some careful and
 106       probably time-consuming design work.  The actual coding, once
 107       that is all done, is probably 2 or 3 days work.
 108       [optional for OF1.3+]
 109
 110     * Per-flow meters.  OpenFlow protocol support is now implemented.
 111       Support for the special OFPM_SLOWPATH and OFPM_CONTROLLER meters
 112       is missing.  Support for the software switch is under review.
 113       [optional for OF1.3+]
 114
 115     * Auxiliary connections.  An implementation in generic code might
 116       be a week's worth of work.  The value of an implementation in
 117       generic code is questionable, though, since much of the benefit
 118       of axuiliary connections is supposed to be to take advantage of
 119       hardware support.  (We could make the kernel module somehow
 120       send packets across the auxiliary connections directly, for
 121       some kind of "hardware" support, if we judged it useful enough.)
 122       [optional for OF1.3+]
 123
 124     * MPLS BoS matching.
 125       Part of MPLS patchset by Simon Horman.
 126       [optional for OF1.3+]
 127
 128     * Provider Backbone Bridge tagging.  I don't plan to implement
 129       this (but we'd accept an implementation).
 130       [optional for OF1.3+]
 131
 132     * Rework tag order.
 133       Part of MPLS patchset by Simon Horman.
 134       [required for v1.3+]
 135
 136     * On-demand flow counters.  I think this might be a real
 137       optimization in some cases for the software switch.
 138       [optional for OF1.3+]
 139
 140 ONF OpenFlow Exensions for 1.3.X Pack1
 141 --------------------------------------
 142
 143 OpenFlow 1.3 has a bunch of ONF extentions.
 144 Many of them are necessary for OpenFlow 1.4 as well.
 145
 146     * Flow entry notifications
 147       This seems to be modelled after OVS's NXST_FLOW_MONITOR.
 148       [EXT-187]
 149       [required for OF1.4+]
 150
 151     * Role Status
 152       [EXT-191]
 153       [required for OF1.4+]
 154
 155     * Flow entry eviction
 156       OVS has flow eviction functionality.
 157       table_mod OFPTC_EVICTION, flow_mod 'importance', and
 158       table_desc ofp_table_mod_prop_eviction need to be implemented.
 159       [EXT-192-e]
 160       [optional for OF1.4+]
 161
 162     * Vacancy events
 163       [EXT-192-v]
 164       [optional for OF1.4+]
 165
 166     * Bundle
 167       Transactional modification.  OpenFlow 1.4 requires to support
 168       flow_mods and port_mods in a bundle.
 169       (Not related to OVS's 'ofbundle' stuff.)
 170       [EXT-230]
 171       [required for OF1.4+]
 172
 173     * Table synchronisation
 174       [EXT-232]
 175       [optional for OF1.4+]
 176
 177     * Group notifications
 178       [EXT-235]
 179       [optional for OF1.4+]
 180
 181     * Bad flow entry priority error
 182       Probably not so useful to the software switch.
 183       [EXT-236]
 184       [optional for OF1.4+]
 185
 186     * Set async config error
 187       [EXT-237]
 188       [optional for OF1.4+]
 189
 190     * PBB UCA header field
 191       [EXT-256]
 192       [optional for OF1.4+]
 193
 194     * Duplicate instruction error
 195       We already have ONFBIC_DUP_INSTRUCTION.
 196       [EXT-260]
 197       [required for OF1.4+]
 198
 199     * Multipart timeout error
 200       [EXT-264]
 201       [required for OF1.4+]
 202
 203 OpenFlow 1.4
 204 ------------
 205
 206     * More extensible wire protocol
 207       Many on-wire structures got TLVs.
 208       [EXT-262]
 209       [required for OF1.4+]
 210
 211     * More descriptive reasons for packet-in
 212       Distinguish OFPR_APPLY_ACTION, OFPR_ACTION_SET, OFPR_GROUP,
 213       OFPR_PACKET_OUT.  NO_MATCH was renamed to OFPR_TABLE_MISS.
 214       [EXT-136]
 215       [required for OF1.4+]
 216
 217     * Optical port properties
 218       [EXT-154]
 219       [optional for OF1.4+]
 220
 221     * Flow-removed reason for meter delete
 222       Report flow removal due to meter deletion with OFPRR_METER_DELETE.
 223       [EXT-261]
 224       [optional for OF1.4+]
 225
 226     * Meter notifications
 227       [EXT-235]
 228       [optional for OF1.4+]
 229
 230 General
 231 -----
 232
 233     * ovs-ofctl(8) often lists as Nicira extensions features that
 234       later OpenFlow versions support in standard ways.
 235
 236 How to contribute
 237 -----------------
 238
 239 If you plan to contribute code for a feature, please let everyone know
 240 on ovs-dev before you start work.  This will help avoid duplicating
 241 work.
 242
 243 Please consider the following:
 244
 245     * Testing.  Please test your code.
 246
 247     * Unit tests.  Please consider writing some.  The tests directory
 248       has many examples that you can use as a starting point.
 249
 250     * ovs-ofctl.  If you add a feature that is useful for some
 251       ovs-ofctl command then you should add support for it there.
 252
 253     * Documentation.  If you add a user-visible feature, then you
 254       should document it in the appropriate manpage and mention it in
 255       NEWS as well.
 256
 257     * Coding style (see the CodingStyle file at the top of the source
 258       tree).
 259
 260     * The patch submission guidelines (see SubmittingPatches).  I
 261       recommend using "git send-email", which automatically follows a
 262       lot of those guidelines.
 263
 264 Bug Reporting
 265 -------------
 266
 267 Please report problems to bugs@openvswitch.org.