[mirror_ovs.git] / OPENFLOW-1.1+

                OpenFlow 1.1+ support in Open vSwitch
                =====================================

Open vSwitch support for OpenFlow 1.1, 1.2, and 1.3 is a work in
progress.  This file describes the work still to be done.

The Plan
--------

OpenFlow version support is not a build-time option.  A single build
of Open vSwitch must be able to handle all supported versions of
OpenFlow.  Ideally, even at runtime it should be able to support all
protocol versions at the same time on different OpenFlow bridges (and
perhaps even on the same bridge).

At the same time, it would be a shame to litter the core of the OVS
code with lots of ugly code concerned with the details of various
OpenFlow protocol versions.

The primary approach to compatibility is to abstract most of the
details of the differences from the core code, by adding a protocol
layer that translates between OF1.x and a slightly higher-level
abstract representation.  The core of this approach is the many struct
ofputil_* structures in lib/ofp-util.h.

As a consequence of this approach, OVS cannot use OpenFlow protocol
definitions that closely resemble those in the OpenFlow specification,
because openflow.h in different versions of the OpenFlow specification
defines the same identifier with different values.  Instead,
openflow-common.h contains definitions that are common to all the
specifications and separate protocol version-specific headers contain
protocol-specific definitions renamed so as not to conflict,
e.g. OFPAT10_ENQUEUE and OFPAT11_ENQUEUE for the OpenFlow 1.0 and 1.1
values for OFPAT_ENQUEUE.  Generally, in cases of conflict, the
protocol layer will define a more abstract OFPUTIL_* or struct
ofputil_*.

Here are the current approaches in a few tricky areas:

    * Port numbering.  OpenFlow 1.0 has 16-bit port numbers and later
      OpenFlow versions have 32-bit port numbers.  For now, OVS
      support for later protocol versions requires all port numbers to
      fall into the 16-bit range, translating the reserved OFPP_* port
      numbers.

    * Actions.  OpenFlow 1.0 and later versions have very different
      ideas of actions.  OVS reconciles by translating all the
      versions' actions (and instructions) to and from a common
      internal representation.

OpenFlow 1.1
------------

The list of remaining work items for OpenFlow 1.1 is below.  It is
probably incomplete.

    * The new in_phy_port field in OFPT_PACKET_IN needs some kind of
      implementation.  It has a sensible interpretation for tunnels
      but in general the physical port is not in the datapath for OVS
      so the value is not necessarily meaningful.  We might have to
      just fix it as the same as in_port.
      [required for OF1.1; optional for OF1.2+]

    * OFPT_TABLE_MOD message.  This is new in OF1.1, so we need to
      implement it.  It should be implemented so that the default OVS
      behavior does not change.
      [required for OF1.1 and OF1.2]

    * MPLS.  Simon Horman maintains a patch series that adds this
      feature.  This is partially merged.
      [optional for OF1.1+]

    * Match and set double-tagged VLANs (QinQ).  This requires kernel
      work for reasonable performance.
      [optional for OF1.1+]

    * VLANs tagged with 88a8 Ethertype.  This requires kernel work for
      reasonable performance.
      [required for OF1.1+]

    * Groups.

        * Type all
          [required for OF1.1+]

        * Type select
          [optional for OF1.1+]

        * Type indirect
          [required for OF1.1+]

        * Type fast failover
          [optional for OF1.1+]

        * Statistics
          [optional for OF1.1+]

OpenFlow 1.2
------------

OpenFlow 1.2 support requires OpenFlow 1.1 as a prerequisite. All the
additional work specific to Openflow 1.2 are complete.  (This is based
on the change log at the end of the OF1.2 spec.  I didn't compare the
specs carefully yet.)

    * Action translation needs some work to transform OpenFlow 1.1
      field modification actions into OpenFlow 1.2+ "set-field"
      actions, because OpenFlow 1.2 dropped support for the OF1.1
      actions.

OpenFlow 1.3
------------

OpenFlow 1.3 support requires OpenFlow 1.2 as a prerequisite, plus the
following additional work.  (This is based on the change log at the
end of the OF1.3 spec, reusing most of the section titles directly.  I
didn't compare the specs carefully yet.)

    * Add support for multipart requests.
      Currently we always report OFPBRC_MULTIPART_BUFFER_OVERFLOW.
      [optional for OF1.3+]

    * Add OFPMP_TABLE_FEATURES statistics.
      [optional for OF1.3+]

    * More flexible table miss support.
      This requires the following.
      - Change the default table-miss action (in the absense of table-miss
        entry) from packet_in to drop for OF1.3+.  Decide what to do if
        a switch is configured to support multiple OF versions.
      [required for OF1.3+]

    * IPv6 extension header handling support.  Fully implementing this
      requires kernel support.  This likely will take some careful and
      probably time-consuming design work.  The actual coding, once
      that is all done, is probably 2 or 3 days work.
      [optional for OF1.3+]

    * Per-flow meters.  Similar to IPv6 extension headers in kernel
      and design requirements.  Might be politically difficult to add
      directly to the kernel module, since its functionality overlaps
      with tc.  Ideally, therefore, we could implement these somehow
      with tc, but I haven't investigated whether that makes sense.
      [optional for OF1.3+]

    * Per-connection event filtering.  OF1.3 adopted Open vSwitch's
      existing design for this feature so implementation should be
      easy.
      [required for OF1.3+]

    * Auxiliary connections.  An implementation in generic code might
      be a week's worth of work.  The value of an implementation in
      generic code is questionable, though, since much of the benefit
      of axuiliary connections is supposed to be to take advantage of
      hardware support.  (We could make the kernel module somehow
      send packets across the auxiliary connections directly, for
      some kind of "hardware" support, if we judged it useful enough.)
      [optional for OF1.3+]

    * MPLS BoS matching.  (Included in Simon's MPLS series?)
      [optional for OF1.3+]

    * Provider Backbone Bridge tagging.  I don't plan to implement
      this (but we'd accept an implementation).
      [optional for OF1.3+]

    * Rework tag order.  I'm not sure whether we need to do anything
      for this. Part of MPLS patchset by Simon Horman.
      [required for v1.3+]

    * On-demand flow counters.  I think this might be a real
      optimization in some cases for the software switch.
      [optional for OF1.3+]

ONF OpenFlow Exensions for 1.3.X Pack1
--------------------------------------

OpenFlow 1.3 has a bunch of ONF extentions.
Many of them are necessary for OpenFlow 1.4 as well.

    * Flow entry notifications
      This seems to be modelled after OVS's NXST_FLOW_MONITOR.
      [EXT-187]
      [required for OF1.4+]

    * Role Status
      [EXT-191]
      [required for OF1.4+]

    * Flow entry eviction
      OVS has flow eviction functionality.
      table_mod OFPTC_EVICTION, flow_mod 'importance', and
      table_desc ofp_table_mod_prop_eviction need to be implemented.
      [EXT-192-e]
      [optional for OF1.4+]

    * Vacancy events
      [EXT-192-v]
      [optional for OF1.4+]

    * Bundle
      Transactional modification.  OpenFlow 1.4 requires to support
      flow_mods and port_mods in a bundle.
      (Not related to OVS's 'ofbundle' stuff.)
      [EXT-230]
      [required for OF1.4+]

    * Table synchronisation
      [EXT-232]
      [optional for OF1.4+]

    * Group notifications
      [EXT-235]
      [optional for OF1.4+]

    * Bad flow entry priority error
      Probably not so useful to the software switch.
      [EXT-236]
      [optional for OF1.4+]

    * Set async config error
      [EXT-237]
      [optional for OF1.4+]

    * PBB UCA header field
      [EXT-256]
      [optional for OF1.4+]

    * Duplicate instruction error
      We already have ONFBIC_DUP_INSTRUCTION.
      [EXT-260]
      [required for OF1.4+]

    * Multipart timeout error
      [EXT-264]
      [required for OF1.4+]

OpenFlow 1.4
------------

    * More extensible wire protocol
      Many on-wire structures got TLVs.
      [EXT-262]
      [required for OF1.4+]

    * More descriptive reasons for packet-in
      Distinguish OFPR_APPLY_ACTION, OFPR_ACTION_SET, OFPR_GROUP,
      OFPR_PACKET_OUT.  NO_MATCH was renamed to OFPR_TABLE_MISS.
      [EXT-136]
      [required for OF1.4+]

    * Optical port properties
      [EXT-154]
      [optional for OF1.4+]

    * Flow-removed reason for meter delete
      Report flow removal due to meter deletion with OFPRR_METER_DELETE.
      [EXT-261]
      [optional for OF1.4+]

    * Meter notifications
      [EXT-235]
      [optional for OF1.4+]

How to contribute
-----------------

If you plan to contribute code for a feature, please let everyone know
on ovs-dev before you start work.  This will help avoid duplicating
work.

Please consider the following:

    * Testing.  Please test your code.

    * Unit tests.  Please consider writing some.  The tests directory
      has many examples that you can use as a starting point.

    * ovs-ofctl.  If you add a feature that is useful for some
      ovs-ofctl command then you should add support for it there.

    * Documentation.  If you add a user-visible feature, then you
      should document it in the appropriate manpage and mention it in
      NEWS as well.

    * Coding style (see the CodingStyle file at the top of the source
      tree).

    * The patch submission guidelines (see SubmittingPatches).  I
      recommend using "git send-email", which automatically follows a
      lot of those guidelines.

Bug Reporting
-------------

Please report problems to bugs@openvswitch.org.
Commit	Line	Data
bea97716 BP	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
bea97716 BP	57	* The new in_phy_port field in OFPT_PACKET_IN needs some kind of
	58	implementation. It has a sensible interpretation for tunnels
	59	but in general the physical port is not in the datapath for OVS
	60	so the value is not necessarily meaningful. We might have to
	61	just fix it as the same as in_port.
4db3f50a	62	[required for OF1.1; optional for OF1.2+]
bea97716	63
4db3f50a	64	* OFPT_TABLE_MOD message. This is new in OF1.1, so we need to
bea97716 BP	65	implement it. It should be implemented so that the default OVS
bea97716 BP	66	behavior does not change.
4db3f50a SH	67	[required for OF1.1 and OF1.2]
4db3f50a SH	68
bea97716	69	* MPLS. Simon Horman maintains a patch series that adds this
ac3d64b1	70	feature. This is partially merged.
4db3f50a	71	[optional for OF1.1+]
bea97716	72
bea97716 BP	73	* Match and set double-tagged VLANs (QinQ). This requires kernel
bea97716 BP	74	work for reasonable performance.
4db3f50a	75	[optional for OF1.1+]
bea97716 BP	76
	77	* VLANs tagged with 88a8 Ethertype. This requires kernel work for
	78	reasonable performance.
4db3f50a	79	[required for OF1.1+]
bea97716 BP	80
	81	* Groups.
	82
4db3f50a SH	83	* Type all
	84	[required for OF1.1+]
	85
	86	* Type select
	87	[optional for OF1.1+]
	88
	89	* Type indirect
	90	[required for OF1.1+]
	91
	92	* Type fast failover
	93	[optional for OF1.1+]
	94
	95	* Statistics
	96	[optional for OF1.1+]
	97
bea97716 BP	98	OpenFlow 1.2
	99	------------
	100
86189a8c GS	101	OpenFlow 1.2 support requires OpenFlow 1.1 as a prerequisite. All the
	102	additional work specific to Openflow 1.2 are complete. (This is based
	103	on the change log at the end of the OF1.2 spec. I didn't compare the
	104	specs carefully yet.)
bea97716	105
260aeca8 BP	106	* Action translation needs some work to transform OpenFlow 1.1
	107	field modification actions into OpenFlow 1.2+ "set-field"
	108	actions, because OpenFlow 1.2 dropped support for the OF1.1
	109	actions.
	110
bea97716 BP	111	OpenFlow 1.3
	112	------------
	113
	114	OpenFlow 1.3 support requires OpenFlow 1.2 as a prerequisite, plus the
	115	following additional work. (This is based on the change log at the
	116	end of the OF1.3 spec, reusing most of the section titles directly. I
b2c9b585	117	didn't compare the specs carefully yet.)
bea97716 BP	118
bea97716 BP	119	* Add support for multipart requests.
ff3c2c63	120	Currently we always report OFPBRC_MULTIPART_BUFFER_OVERFLOW.
4db3f50a	121	[optional for OF1.3+]
bea97716 BP	122
bea97716 BP	123	* Add OFPMP_TABLE_FEATURES statistics.
4db3f50a	124	[optional for OF1.3+]
bea97716 BP	125
bea97716 BP	126	* More flexible table miss support.
48a5f330 YT	127	This requires the following.
	128	- Change the default table-miss action (in the absense of table-miss
	129	entry) from packet_in to drop for OF1.3+. Decide what to do if
	130	a switch is configured to support multiple OF versions.
4db3f50a	131	[required for OF1.3+]
bea97716 BP	132
	133	* IPv6 extension header handling support. Fully implementing this
	134	requires kernel support. This likely will take some careful and
	135	probably time-consuming design work. The actual coding, once
	136	that is all done, is probably 2 or 3 days work.
4db3f50a	137	[optional for OF1.3+]
bea97716 BP	138
	139	* Per-flow meters. Similar to IPv6 extension headers in kernel
	140	and design requirements. Might be politically difficult to add
	141	directly to the kernel module, since its functionality overlaps
	142	with tc. Ideally, therefore, we could implement these somehow
b2c9b585	143	with tc, but I haven't investigated whether that makes sense.
4db3f50a	144	[optional for OF1.3+]
bea97716	145
ac3d64b1	146	* Per-connection event filtering. OF1.3 adopted Open vSwitch's
bea97716 BP	147	existing design for this feature so implementation should be
bea97716 BP	148	easy.
4db3f50a	149	[required for OF1.3+]
bea97716	150
4db3f50a SH	151	* Auxiliary connections. An implementation in generic code might
	152	be a week's worth of work. The value of an implementation in
	153	generic code is questionable, though, since much of the benefit
	154	of axuiliary connections is supposed to be to take advantage of
	155	hardware support. (We could make the kernel module somehow
	156	send packets across the auxiliary connections directly, for
	157	some kind of "hardware" support, if we judged it useful enough.)
	158	[optional for OF1.3+]
bea97716 BP	159
bea97716 BP	160	* MPLS BoS matching. (Included in Simon's MPLS series?)
4db3f50a	161	[optional for OF1.3+]
bea97716	162
b2c9b585 BP	163	* Provider Backbone Bridge tagging. I don't plan to implement
b2c9b585 BP	164	this (but we'd accept an implementation).
4db3f50a	165	[optional for OF1.3+]
bea97716	166
b2c9b585	167	* Rework tag order. I'm not sure whether we need to do anything
4db3f50a SH	168	for this. Part of MPLS patchset by Simon Horman.
4db3f50a SH	169	[required for v1.3+]
bea97716	170
bea97716 BP	171	* On-demand flow counters. I think this might be a real
bea97716 BP	172	optimization in some cases for the software switch.
4db3f50a SH	173	[optional for OF1.3+]
4db3f50a SH	174
9fa96468 YT	175	ONF OpenFlow Exensions for 1.3.X Pack1
	176	--------------------------------------
	177
	178	OpenFlow 1.3 has a bunch of ONF extentions.
	179	Many of them are necessary for OpenFlow 1.4 as well.
	180
	181	* Flow entry notifications
	182	This seems to be modelled after OVS's NXST_FLOW_MONITOR.
	183	[EXT-187]
	184	[required for OF1.4+]
	185
	186	* Role Status
	187	[EXT-191]
	188	[required for OF1.4+]
	189
	190	* Flow entry eviction
	191	OVS has flow eviction functionality.
	192	table_mod OFPTC_EVICTION, flow_mod 'importance', and
	193	table_desc ofp_table_mod_prop_eviction need to be implemented.
	194	[EXT-192-e]
	195	[optional for OF1.4+]
	196
	197	* Vacancy events
	198	[EXT-192-v]
	199	[optional for OF1.4+]
	200
	201	* Bundle
	202	Transactional modification. OpenFlow 1.4 requires to support
	203	flow_mods and port_mods in a bundle.
	204	(Not related to OVS's 'ofbundle' stuff.)
	205	[EXT-230]
	206	[required for OF1.4+]
	207
	208	* Table synchronisation
	209	[EXT-232]
	210	[optional for OF1.4+]
	211
	212	* Group notifications
	213	[EXT-235]
	214	[optional for OF1.4+]
	215
	216	* Bad flow entry priority error
	217	Probably not so useful to the software switch.
	218	[EXT-236]
	219	[optional for OF1.4+]
	220
	221	* Set async config error
	222	[EXT-237]
	223	[optional for OF1.4+]
	224
	225	* PBB UCA header field
	226	[EXT-256]
	227	[optional for OF1.4+]
	228
	229	* Duplicate instruction error
	230	We already have ONFBIC_DUP_INSTRUCTION.
	231	[EXT-260]
	232	[required for OF1.4+]
	233
	234	* Multipart timeout error
	235	[EXT-264]
	236	[required for OF1.4+]
	237
	238	OpenFlow 1.4
239	------------
240
241	* More extensible wire protocol
242	Many on-wire structures got TLVs.
243	[EXT-262]
244	[required for OF1.4+]
245
246	* More descriptive reasons for packet-in
247	Distinguish OFPR_APPLY_ACTION, OFPR_ACTION_SET, OFPR_GROUP,
248	OFPR_PACKET_OUT. NO_MATCH was renamed to OFPR_TABLE_MISS.
249	[EXT-136]
250	[required for OF1.4+]
251
252	* Optical port properties
253	[EXT-154]
254	[optional for OF1.4+]
255
256	* Flow-removed reason for meter delete
257	Report flow removal due to meter deletion with OFPRR_METER_DELETE.
258	[EXT-261]
259	[optional for OF1.4+]
260
261	* Meter notifications
262	[EXT-235]
263	[optional for OF1.4+]
bea97716 BP	264
	265	How to contribute
	266	-----------------
	267
	268	If you plan to contribute code for a feature, please let everyone know
	269	on ovs-dev before you start work. This will help avoid duplicating
	270	work.
	271
	272	Please consider the following:
	273
	274	* Testing. Please test your code.
	275
	276	* Unit tests. Please consider writing some. The tests directory
	277	has many examples that you can use as a starting point.
	278
	279	* ovs-ofctl. If you add a feature that is useful for some
	280	ovs-ofctl command then you should add support for it there.
	281
	282	* Documentation. If you add a user-visible feature, then you
	283	should document it in the appropriate manpage and mention it in
	284	NEWS as well.
	285
	286	* Coding style (see the CodingStyle file at the top of the source
	287	tree).
	288
	289	* The patch submission guidelines (see SubmittingPatches). I
b2c9b585	290	recommend using "git send-email", which automatically follows a
bea97716 BP	291	lot of those guidelines.
	292
	293	Bug Reporting
	294	-------------
	295
	296	Please report problems to bugs@openvswitch.org.