[ovs.git] / OPENFLOW-1.1+

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

Open vSwitch support for OpenFlow 1.1 and beyond 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.

    * 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.  Alexander Wu has posted a
      patch series.  [optional 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+]

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

    * 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
c37c0382	4	Open vSwitch support for OpenFlow 1.1 and beyond is a work in
bea97716 BP	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	57	* MPLS. Simon Horman maintains a patch series that adds this
ac3d64b1	58	feature. This is partially merged.
4db3f50a	59	[optional for OF1.1+]
bea97716	60
bea97716 BP	61	* Match and set double-tagged VLANs (QinQ). This requires kernel
bea97716 BP	62	work for reasonable performance.
4db3f50a	63	[optional for OF1.1+]
bea97716 BP	64
	65	* VLANs tagged with 88a8 Ethertype. This requires kernel work for
	66	reasonable performance.
4db3f50a	67	[required for OF1.1+]
bea97716	68
bea97716 BP	69	OpenFlow 1.2
	70	------------
	71
86189a8c GS	72	OpenFlow 1.2 support requires OpenFlow 1.1 as a prerequisite. All the
	73	additional work specific to Openflow 1.2 are complete. (This is based
	74	on the change log at the end of the OF1.2 spec. I didn't compare the
	75	specs carefully yet.)
bea97716	76
bea97716 BP	77	OpenFlow 1.3
	78	------------
	79
	80	OpenFlow 1.3 support requires OpenFlow 1.2 as a prerequisite, plus the
	81	following additional work. (This is based on the change log at the
	82	end of the OF1.3 spec, reusing most of the section titles directly. I
b2c9b585	83	didn't compare the specs carefully yet.)
bea97716 BP	84
bea97716 BP	85	* Add support for multipart requests.
ff3c2c63	86	Currently we always report OFPBRC_MULTIPART_BUFFER_OVERFLOW.
4db3f50a	87	[optional for OF1.3+]
bea97716	88
e2c42ed0 BP	89	* Add OFPMP_TABLE_FEATURES statistics. Alexander Wu has posted a
e2c42ed0 BP	90	patch series. [optional for OF1.3+]
bea97716	91
bea97716 BP	92	* IPv6 extension header handling support. Fully implementing this
	93	requires kernel support. This likely will take some careful and
	94	probably time-consuming design work. The actual coding, once
	95	that is all done, is probably 2 or 3 days work.
4db3f50a	96	[optional for OF1.3+]
bea97716	97
e34afc3f BP	98	* Per-flow meters. OpenFlow protocol support is now implemented.
	99	Support for the special OFPM_SLOWPATH and OFPM_CONTROLLER meters
	100	is missing. Support for the software switch is under review.
4db3f50a	101	[optional for OF1.3+]
bea97716	102
4db3f50a SH	103	* Auxiliary connections. An implementation in generic code might
	104	be a week's worth of work. The value of an implementation in
	105	generic code is questionable, though, since much of the benefit
	106	of axuiliary connections is supposed to be to take advantage of
	107	hardware support. (We could make the kernel module somehow
	108	send packets across the auxiliary connections directly, for
	109	some kind of "hardware" support, if we judged it useful enough.)
	110	[optional for OF1.3+]
bea97716	111
b2c9b585 BP	112	* Provider Backbone Bridge tagging. I don't plan to implement
b2c9b585 BP	113	this (but we'd accept an implementation).
4db3f50a	114	[optional for OF1.3+]
bea97716	115
bea97716 BP	116	* On-demand flow counters. I think this might be a real
bea97716 BP	117	optimization in some cases for the software switch.
4db3f50a SH	118	[optional for OF1.3+]
4db3f50a SH	119
9fa96468 YT	120	ONF OpenFlow Exensions for 1.3.X Pack1
	121	--------------------------------------
	122
	123	OpenFlow 1.3 has a bunch of ONF extentions.
	124	Many of them are necessary for OpenFlow 1.4 as well.
	125
	126	* Flow entry notifications
	127	This seems to be modelled after OVS's NXST_FLOW_MONITOR.
	128	[EXT-187]
	129	[required for OF1.4+]
	130
	131	* Role Status
	132	[EXT-191]
	133	[required for OF1.4+]
	134
	135	* Flow entry eviction
	136	OVS has flow eviction functionality.
	137	table_mod OFPTC_EVICTION, flow_mod 'importance', and
	138	table_desc ofp_table_mod_prop_eviction need to be implemented.
	139	[EXT-192-e]
	140	[optional for OF1.4+]
	141
	142	* Vacancy events
	143	[EXT-192-v]
	144	[optional for OF1.4+]
	145
	146	* Bundle
	147	Transactional modification. OpenFlow 1.4 requires to support
	148	flow_mods and port_mods in a bundle.
	149	(Not related to OVS's 'ofbundle' stuff.)
	150	[EXT-230]
	151	[required for OF1.4+]
	152
	153	* Table synchronisation
	154	[EXT-232]
	155	[optional for OF1.4+]
	156
	157	* Group notifications
	158	[EXT-235]
	159	[optional for OF1.4+]
	160
	161	* Bad flow entry priority error
	162	Probably not so useful to the software switch.
	163	[EXT-236]
	164	[optional for OF1.4+]
	165
	166	* Set async config error
	167	[EXT-237]
	168	[optional for OF1.4+]
	169
	170	* PBB UCA header field
	171	[EXT-256]
	172	[optional for OF1.4+]
	173
	174	* Duplicate instruction error
	175	We already have ONFBIC_DUP_INSTRUCTION.
	176	[EXT-260]
	177	[required for OF1.4+]
	178
	179	* Multipart timeout error
	180	[EXT-264]
	181	[required for OF1.4+]
	182
	183	OpenFlow 1.4
184	------------
185
186	* More extensible wire protocol
187	Many on-wire structures got TLVs.
188	[EXT-262]
189	[required for OF1.4+]
190
191	* More descriptive reasons for packet-in
192	Distinguish OFPR_APPLY_ACTION, OFPR_ACTION_SET, OFPR_GROUP,
193	OFPR_PACKET_OUT. NO_MATCH was renamed to OFPR_TABLE_MISS.
194	[EXT-136]
195	[required for OF1.4+]
196
197	* Optical port properties
198	[EXT-154]
199	[optional for OF1.4+]
200
201	* Flow-removed reason for meter delete
202	Report flow removal due to meter deletion with OFPRR_METER_DELETE.
203	[EXT-261]
204	[optional for OF1.4+]
205
206	* Meter notifications
207	[EXT-235]
208	[optional for OF1.4+]
bea97716	209
70d0aed3 BP	210	General
	211	-----
	212
	213	* ovs-ofctl(8) often lists as Nicira extensions features that
	214	later OpenFlow versions support in standard ways.
	215
bea97716 BP	216	How to contribute
	217	-----------------
	218
	219	If you plan to contribute code for a feature, please let everyone know
	220	on ovs-dev before you start work. This will help avoid duplicating
	221	work.
	222
	223	Please consider the following:
	224
	225	* Testing. Please test your code.
	226
	227	* Unit tests. Please consider writing some. The tests directory
	228	has many examples that you can use as a starting point.
	229
	230	* ovs-ofctl. If you add a feature that is useful for some
	231	ovs-ofctl command then you should add support for it there.
	232
	233	* Documentation. If you add a user-visible feature, then you
	234	should document it in the appropriate manpage and mention it in
	235	NEWS as well.
	236
	237	* Coding style (see the CodingStyle file at the top of the source
	238	tree).
	239
	240	* The patch submission guidelines (see SubmittingPatches). I
b2c9b585	241	recommend using "git send-email", which automatically follows a
bea97716 BP	242	lot of those guidelines.
	243
	244	Bug Reporting
	245	-------------
	246
	247	Please report problems to bugs@openvswitch.org.