1 OpenFlow 1.1+ support in Open vSwitch
2 =====================================
4 Open vSwitch support for OpenFlow 1.1 and beyond 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 * Match and set double-tagged VLANs (QinQ). This requires kernel
58 work for reasonable performance.
61 * VLANs tagged with 88a8 Ethertype. This requires kernel work for
62 reasonable performance.
68 OpenFlow 1.2 support requires OpenFlow 1.1 as a prerequisite. All the
69 additional work specific to Openflow 1.2 are complete. (This is based
70 on the change log at the end of the OF1.2 spec. I didn't compare the
76 OpenFlow 1.3 support requires OpenFlow 1.2 as a prerequisite, plus the
77 following additional work. (This is based on the change log at the
78 end of the OF1.3 spec, reusing most of the section titles directly. I
79 didn't compare the specs carefully yet.)
81 * Add support for multipart requests.
82 Currently we always report OFPBRC_MULTIPART_BUFFER_OVERFLOW.
85 * Add OFPMP_TABLE_FEATURES statistics. Alexander Wu has posted a
86 patch series. [optional for OF1.3+]
88 * IPv6 extension header handling support. Fully implementing this
89 requires kernel support. This likely will take some careful and
90 probably time-consuming design work. The actual coding, once
91 that is all done, is probably 2 or 3 days work.
94 * Per-flow meters. OpenFlow protocol support is now implemented.
95 Support for the special OFPM_SLOWPATH and OFPM_CONTROLLER meters
96 is missing. Support for the software switch is under review.
99 * Auxiliary connections. An implementation in generic code might
100 be a week's worth of work. The value of an implementation in
101 generic code is questionable, though, since much of the benefit
102 of axuiliary connections is supposed to be to take advantage of
103 hardware support. (We could make the kernel module somehow
104 send packets across the auxiliary connections directly, for
105 some kind of "hardware" support, if we judged it useful enough.)
106 [optional for OF1.3+]
108 * Provider Backbone Bridge tagging. I don't plan to implement
109 this (but we'd accept an implementation).
110 [optional for OF1.3+]
112 * On-demand flow counters. I think this might be a real
113 optimization in some cases for the software switch.
114 [optional for OF1.3+]
116 ONF OpenFlow Exensions for 1.3.X Pack1
117 --------------------------------------
119 OpenFlow 1.3 has a bunch of ONF extentions.
120 Many of them are necessary for OpenFlow 1.4 as well.
122 * Flow entry notifications
123 This seems to be modelled after OVS's NXST_FLOW_MONITOR.
124 (Simon Horman is working on this.)
126 [required for OF1.4+]
130 [required for OF1.4+]
132 * Flow entry eviction
133 OVS has flow eviction functionality.
134 table_mod OFPTC_EVICTION, flow_mod 'importance', and
135 table_desc ofp_table_mod_prop_eviction need to be implemented.
137 [optional for OF1.4+]
141 [optional for OF1.4+]
144 Transactional modification. OpenFlow 1.4 requires to support
145 flow_mods and port_mods in a bundle.
146 (Not related to OVS's 'ofbundle' stuff.)
148 [required for OF1.4+]
150 * Table synchronisation
152 [optional for OF1.4+]
154 * Group notifications
156 [optional for OF1.4+]
158 * Bad flow entry priority error
159 Probably not so useful to the software switch.
161 [optional for OF1.4+]
163 * Set async config error
165 [optional for OF1.4+]
167 * PBB UCA header field
169 [optional for OF1.4+]
171 * Multipart timeout error
173 [required for OF1.4+]
178 * More extensible wire protocol
179 Many on-wire structures got TLVs.
181 [required for OF1.4+]
183 * More descriptive reasons for packet-in
184 Distinguish OFPR_APPLY_ACTION, OFPR_ACTION_SET, OFPR_GROUP,
185 OFPR_PACKET_OUT. NO_MATCH was renamed to OFPR_TABLE_MISS.
187 [required for OF1.4+]
189 * Optical port properties
191 [optional for OF1.4+]
193 * Meter notifications
195 [optional for OF1.4+]
200 * ovs-ofctl(8) often lists as Nicira extensions features that
201 later OpenFlow versions support in standard ways.
206 If you plan to contribute code for a feature, please let everyone know
207 on ovs-dev before you start work. This will help avoid duplicating
210 Please consider the following:
212 * Testing. Please test your code.
214 * Unit tests. Please consider writing some. The tests directory
215 has many examples that you can use as a starting point.
217 * ovs-ofctl. If you add a feature that is useful for some
218 ovs-ofctl command then you should add support for it there.
220 * Documentation. If you add a user-visible feature, then you
221 should document it in the appropriate manpage and mention it in
224 * Coding style (see the CodingStyle file at the top of the source
227 * The patch submission guidelines (see CONTRIBUTING). I
228 recommend using "git send-email", which automatically follows a
229 lot of those guidelines.
234 Please report problems to bugs@openvswitch.org.