[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.

    * 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+]

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.)

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.  OpenFlow protocol support is now implemented.
      Support for the special OFPM_SLOWPATH and OFPM_CONTROLLER meters
      is missing.  Support for the software switch is under review.
      [optional 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.
      Part of MPLS patchset by Simon Horman.
      [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.
      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+]

General
-----

    * ovs-ofctl(8) often lists as Nicira extensions features that
      later OpenFlow versions support in standard ways.

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
4db3f50a	57	* OFPT_TABLE_MOD message. This is new in OF1.1, so we need to
bea97716 BP	58	implement it. It should be implemented so that the default OVS
bea97716 BP	59	behavior does not change.
4db3f50a SH	60	[required for OF1.1 and OF1.2]
4db3f50a SH	61
bea97716	62	* MPLS. Simon Horman maintains a patch series that adds this
ac3d64b1	63	feature. This is partially merged.
4db3f50a	64	[optional for OF1.1+]
bea97716	65
bea97716 BP	66	* Match and set double-tagged VLANs (QinQ). This requires kernel
bea97716 BP	67	work for reasonable performance.
4db3f50a	68	[optional for OF1.1+]
bea97716 BP	69
	70	* VLANs tagged with 88a8 Ethertype. This requires kernel work for
	71	reasonable performance.
4db3f50a	72	[required for OF1.1+]
bea97716	73
bea97716 BP	74	OpenFlow 1.2
	75	------------
	76
86189a8c GS	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.)
bea97716	81
bea97716 BP	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
b2c9b585	88	didn't compare the specs carefully yet.)
bea97716 BP	89
bea97716 BP	90	* Add support for multipart requests.
ff3c2c63	91	Currently we always report OFPBRC_MULTIPART_BUFFER_OVERFLOW.
4db3f50a	92	[optional for OF1.3+]
bea97716 BP	93
bea97716 BP	94	* Add OFPMP_TABLE_FEATURES statistics.
4db3f50a	95	[optional for OF1.3+]
bea97716 BP	96
bea97716 BP	97	* More flexible table miss support.
48a5f330 YT	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.
4db3f50a	102	[required for OF1.3+]
bea97716 BP	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.
4db3f50a	108	[optional for OF1.3+]
bea97716	109
e34afc3f BP	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.
4db3f50a	113	[optional for OF1.3+]
bea97716	114
4db3f50a SH	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+]
bea97716	123
c39f3d73 SH	124	* MPLS BoS matching.
c39f3d73 SH	125	Part of MPLS patchset by Simon Horman.
4db3f50a	126	[optional for OF1.3+]
bea97716	127
b2c9b585 BP	128	* Provider Backbone Bridge tagging. I don't plan to implement
b2c9b585 BP	129	this (but we'd accept an implementation).
4db3f50a	130	[optional for OF1.3+]
bea97716	131
c39f3d73 SH	132	* Rework tag order.
c39f3d73 SH	133	Part of MPLS patchset by Simon Horman.
4db3f50a	134	[required for v1.3+]
bea97716	135
bea97716 BP	136	* On-demand flow counters. I think this might be a real
bea97716 BP	137	optimization in some cases for the software switch.
4db3f50a SH	138	[optional for OF1.3+]
4db3f50a SH	139
9fa96468 YT	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+]
bea97716	229
70d0aed3 BP	230	General
	231	-----
	232
	233	* ovs-ofctl(8) often lists as Nicira extensions features that
	234	later OpenFlow versions support in standard ways.
	235
bea97716 BP	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
b2c9b585	261	recommend using "git send-email", which automatically follows a
bea97716 BP	262	lot of those guidelines.
	263
	264	Bug Reporting
	265	-------------
	266
	267	Please report problems to bugs@openvswitch.org.