1 OpenFlow 1.1+ support in Open vSwitch
2 =====================================
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.
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).
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.
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.
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
38 Here are the current approaches in a few tricky areas:
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
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.
54 The list of remaining work items for OpenFlow 1.1 is below. It is
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.
62 [required for OF1.1; optional for OF1.2+]
64 * OFPT_TABLE_MOD message. This is new in OF1.1, so we need to
65 implement it. It should be implemented so that the default OVS
66 behavior does not change.
67 [required for OF1.1 and OF1.2]
69 * MPLS. Simon Horman maintains a patch series that adds this
70 feature. This is partially merged.
73 * Match and set double-tagged VLANs (QinQ). This requires kernel
74 work for reasonable performance.
77 * VLANs tagged with 88a8 Ethertype. This requires kernel work for
78 reasonable performance.
84 OpenFlow 1.2 support requires OpenFlow 1.1 as a prerequisite. All the
85 additional work specific to Openflow 1.2 are complete. (This is based
86 on the change log at the end of the OF1.2 spec. I didn't compare the
89 * Action translation needs some work to transform OpenFlow 1.1
90 field modification actions into OpenFlow 1.2+ "set-field"
91 actions, because OpenFlow 1.2 dropped support for the OF1.1
97 OpenFlow 1.3 support requires OpenFlow 1.2 as a prerequisite, plus the
98 following additional work. (This is based on the change log at the
99 end of the OF1.3 spec, reusing most of the section titles directly. I
100 didn't compare the specs carefully yet.)
102 * Add support for multipart requests.
103 Currently we always report OFPBRC_MULTIPART_BUFFER_OVERFLOW.
104 [optional for OF1.3+]
106 * Add OFPMP_TABLE_FEATURES statistics.
107 [optional for OF1.3+]
109 * More flexible table miss support.
110 This requires the following.
111 - Change the default table-miss action (in the absense of table-miss
112 entry) from packet_in to drop for OF1.3+. Decide what to do if
113 a switch is configured to support multiple OF versions.
114 [required for OF1.3+]
116 * IPv6 extension header handling support. Fully implementing this
117 requires kernel support. This likely will take some careful and
118 probably time-consuming design work. The actual coding, once
119 that is all done, is probably 2 or 3 days work.
120 [optional for OF1.3+]
122 * Per-flow meters. OpenFlow protocol support is now implemented.
123 Support for the special OFPM_SLOWPATH and OFPM_CONTROLLER meters
124 is missing. Support for the software switch is under review.
125 [optional for OF1.3+]
127 * Per-connection event filtering. OF1.3 adopted Open vSwitch's
128 existing design for this feature so implementation should be
130 [required for OF1.3+]
132 * Auxiliary connections. An implementation in generic code might
133 be a week's worth of work. The value of an implementation in
134 generic code is questionable, though, since much of the benefit
135 of axuiliary connections is supposed to be to take advantage of
136 hardware support. (We could make the kernel module somehow
137 send packets across the auxiliary connections directly, for
138 some kind of "hardware" support, if we judged it useful enough.)
139 [optional for OF1.3+]
142 Part of MPLS patchset by Simon Horman.
143 [optional for OF1.3+]
145 * Provider Backbone Bridge tagging. I don't plan to implement
146 this (but we'd accept an implementation).
147 [optional for OF1.3+]
150 Part of MPLS patchset by Simon Horman.
153 * On-demand flow counters. I think this might be a real
154 optimization in some cases for the software switch.
155 [optional for OF1.3+]
157 ONF OpenFlow Exensions for 1.3.X Pack1
158 --------------------------------------
160 OpenFlow 1.3 has a bunch of ONF extentions.
161 Many of them are necessary for OpenFlow 1.4 as well.
163 * Flow entry notifications
164 This seems to be modelled after OVS's NXST_FLOW_MONITOR.
166 [required for OF1.4+]
170 [required for OF1.4+]
172 * Flow entry eviction
173 OVS has flow eviction functionality.
174 table_mod OFPTC_EVICTION, flow_mod 'importance', and
175 table_desc ofp_table_mod_prop_eviction need to be implemented.
177 [optional for OF1.4+]
181 [optional for OF1.4+]
184 Transactional modification. OpenFlow 1.4 requires to support
185 flow_mods and port_mods in a bundle.
186 (Not related to OVS's 'ofbundle' stuff.)
188 [required for OF1.4+]
190 * Table synchronisation
192 [optional for OF1.4+]
194 * Group notifications
196 [optional for OF1.4+]
198 * Bad flow entry priority error
199 Probably not so useful to the software switch.
201 [optional for OF1.4+]
203 * Set async config error
205 [optional for OF1.4+]
207 * PBB UCA header field
209 [optional for OF1.4+]
211 * Duplicate instruction error
212 We already have ONFBIC_DUP_INSTRUCTION.
214 [required for OF1.4+]
216 * Multipart timeout error
218 [required for OF1.4+]
223 * More extensible wire protocol
224 Many on-wire structures got TLVs.
226 [required for OF1.4+]
228 * More descriptive reasons for packet-in
229 Distinguish OFPR_APPLY_ACTION, OFPR_ACTION_SET, OFPR_GROUP,
230 OFPR_PACKET_OUT. NO_MATCH was renamed to OFPR_TABLE_MISS.
232 [required for OF1.4+]
234 * Optical port properties
236 [optional for OF1.4+]
238 * Flow-removed reason for meter delete
239 Report flow removal due to meter deletion with OFPRR_METER_DELETE.
241 [optional for OF1.4+]
243 * Meter notifications
245 [optional for OF1.4+]
250 * ovs-ofctl(8) often lists as Nicira extensions features that
251 later OpenFlow versions support in standard ways.
256 If you plan to contribute code for a feature, please let everyone know
257 on ovs-dev before you start work. This will help avoid duplicating
260 Please consider the following:
262 * Testing. Please test your code.
264 * Unit tests. Please consider writing some. The tests directory
265 has many examples that you can use as a starting point.
267 * ovs-ofctl. If you add a feature that is useful for some
268 ovs-ofctl command then you should add support for it there.
270 * Documentation. If you add a user-visible feature, then you
271 should document it in the appropriate manpage and mention it in
274 * Coding style (see the CodingStyle file at the top of the source
277 * The patch submission guidelines (see SubmittingPatches). I
278 recommend using "git send-email", which automatically follows a
279 lot of those guidelines.
284 Please report problems to bugs@openvswitch.org.