Openflow switch-v1.5.0.noipr

OpenFlow Switch SpecificationVersion 1.5.0 ( Protocol version 0x06 )

December 19, 2014

ONF TS-020

Copyright 2014; Open Networking Foundation

OpenFlow Switch Specification Version 1.5.0

Disclaimer

THIS SPECIFICATION HAS BEEN APPROVED BY THE BOARD OF DIRECTORS OFTHE OPEN NETWORKING FOUNDATION (ONF) BUT WILL NOT BE A FINAL SPEC-IFICATION UNTIL RATIFIED BY THE MEMBERS PER ONFS POLICIES AND PRO-CEDURES. THE CONTENTS OF THIS SPECIFICATION MAY BE CHANGED PRIORTO PUBLICATION AND SUCH CHANGES MAY INCLUDE THE ADDITION OR DELE-TION OF NECESSARY CLAIMS OF PATENT AND OTHER INTELLECTUAL PROPERTYRIGHTS. THEREFORE, ONF PROVIDES THIS SPECIFICATION TO YOU ON AN AS ISBASIS, AND WITHOUT WARRANTY OF ANY KIND.THIS SPECIFICATION IS PROVIDED AS IS WITH NO WARRANTIES WHATSOEVER,INCLUDING ANY WARRANTY OF MERCHANTABILITY, NONINFRINGEMENT, FIT-NESS FOR ANY PARTICULAR PURPOSE, OR ANY WARRANTY OTHERWISE ARISINGOUT OF ANY PROPOSAL, SPECIFICATION OR SAMPLE. Without limitation, ONF dis-claims all liability, including liability for infringement of any proprietary rights, relating to useof information in this specification and to the implementation of this specification, and ONFdisclaims all liability for cost of procurement of substitute goods or services, lost profits, loss ofuse, loss of data or any incidental, consequential, direct, indirect, or special damages, whetherunder contract, tort, warranty or otherwise, arising in any way out of use or reliance upon thisspecification or any information herein.No license, express or implied, by estoppel or otherwise, to any Open Networking Foundation orOpen Networking Foundation member intellectual property rights is granted herein.Except that a license is hereby granted by ONF to copy and reproduce this specification forinternal use only.Contact the Open Networking Foundation at http://www.opennetworking.org for informationon specification licensing through membership agreements.Any marks and brands contained herein are the property of their respective owners.

Contents1 Introduction 11

2 Switch Components 11

3 Glossary 12

4 OpenFlow Ports 154.1 OpenFlow Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.2 Standard Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.3 Physical Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.4 Logical Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.5 Reserved Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2 2014; The Open Networking Foundation

http://www.opennetworking.org


4.6 Port changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174.7 Port recirculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

5 OpenFlow Tables 185.1 Pipeline Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

5.1.1 Pipeline Consistency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215.2 Flow Tables and flow entries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225.3 Matching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225.4 Table-miss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245.5 Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255.6 Action Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265.7 List of Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275.8 Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

5.8.1 Default values for fields on push . . . . . . . . . . . . . . . . . . . . . . . . . . . 305.9 Counters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315.10 Group Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.10.1 Group Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335.11 Meter Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

5.11.1 Meter Bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345.12 Ingress and egress processing differences . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

6 OpenFlow Channel and Control Channel 356.1 OpenFlow Switch Protocol Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6.1.1 Controller-to-Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366.1.2 Asynchronous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376.1.3 Symmetric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

6.2 Message Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386.3 OpenFlow Channel Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

6.3.1 Connection URI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406.3.2 Connection Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406.3.3 Connection Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416.3.4 Connection Interruption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426.3.5 Encryption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426.3.6 Multiple Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436.3.7 Auxiliary Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

6.4 Flow Table Modification Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476.5 Flow Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 496.6 Flow Table Synchronisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506.7 Group Table Modification Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516.8 Meter Modification Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 546.9 Bundle Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

6.9.1 Bundle overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 546.9.2 Bundle example usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556.9.3 Bundle error processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556.9.4 Bundle atomic modifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566.9.5 Bundle parallelism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56



6.9.6 Scheduled Bundles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 576.9.6.1 The Scheduled Bundle Procedure . . . . . . . . . . . . . . . . . . . . . 576.9.6.2 Discarding Scheduled Bundles . . . . . . . . . . . . . . . . . . . . . . . 586.9.6.3 Timekeeping and Synchronization . . . . . . . . . . . . . . . . . . . . . 586.9.6.4 Scheduling Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

7 The OpenFlow Switch Protocol 597.1 Protocol basic format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

7.1.1 OpenFlow Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 607.1.2 Padding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 617.1.3 Reserved and unsupported values and bit positions . . . . . . . . . . . . . . . . . 62

7.2 Common Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 637.2.1 Port Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7.2.1.1 Port Description Structures . . . . . . . . . . . . . . . . . . . . . . . . . 637.2.1.2 Port Description Properties . . . . . . . . . . . . . . . . . . . . . . . . . 65

7.2.2 Header Types Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 697.2.3 Flow Match Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

7.2.3.1 Flow Match Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 707.2.3.2 Flow Match Field Structures . . . . . . . . . . . . . . . . . . . . . . . . 717.2.3.3 OXM classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 727.2.3.4 Flow Matching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 737.2.3.5 Flow Match Field Masking . . . . . . . . . . . . . . . . . . . . . . . . . 737.2.3.6 Flow Match Field Prerequisite . . . . . . . . . . . . . . . . . . . . . . . 747.2.3.7 Flow Match Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 757.2.3.8 Header Match Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . 777.2.3.9 Pipeline Match Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . 807.2.3.10 Packet registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 817.2.3.11 Packet Type Match Field . . . . . . . . . . . . . . . . . . . . . . . . . . 827.2.3.12 Experimenter Flow Match Fields . . . . . . . . . . . . . . . . . . . . . . 83

7.2.4 Flow Stats Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 837.2.4.1 Flow Stats Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 837.2.4.2 Flow Stat Field Structures . . . . . . . . . . . . . . . . . . . . . . . . . 847.2.4.3 OXS classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 857.2.4.4 Flow Stat Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 857.2.4.5 Experimenter Flow Stat Fields . . . . . . . . . . . . . . . . . . . . . . . 86

7.2.5 Flow Instruction Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 877.2.6 Action Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

7.2.6.1 Output Action Structures . . . . . . . . . . . . . . . . . . . . . . . . . . 907.2.6.2 Group Action Structures . . . . . . . . . . . . . . . . . . . . . . . . . . 917.2.6.3 Set-Queue Action Structure . . . . . . . . . . . . . . . . . . . . . . . . . 917.2.6.4 Meter Action Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . 927.2.6.5 TTL Actions Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . 927.2.6.6 Push and Pop Actions Structures . . . . . . . . . . . . . . . . . . . . . 937.2.6.7 Set-Field Action Structure . . . . . . . . . . . . . . . . . . . . . . . . . 957.2.6.8 Copy-Field Action Structure . . . . . . . . . . . . . . . . . . . . . . . . 967.2.6.9 Experimenter Action Structure . . . . . . . . . . . . . . . . . . . . . . . 97

7.2.7 Controller Status Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97



7.2.8 Experimenter Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 997.3 Controller-to-Switch Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

7.3.1 Handshake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1007.3.2 Switch Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1027.3.3 Flow Table Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1027.3.4 Modify State Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

7.3.4.1 Modify Flow Table Message . . . . . . . . . . . . . . . . . . . . . . . . 1037.3.4.2 Modify Flow Entry Message . . . . . . . . . . . . . . . . . . . . . . . . 1067.3.4.3 Modify Group Entry Message . . . . . . . . . . . . . . . . . . . . . . . . 1097.3.4.4 Port Modification Message . . . . . . . . . . . . . . . . . . . . . . . . . 1157.3.4.5 Meter Modification Message . . . . . . . . . . . . . . . . . . . . . . . . 117

7.3.5 Multipart Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1207.3.5.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1237.3.5.2 Individual Flow Descriptions . . . . . . . . . . . . . . . . . . . . . . . . 1247.3.5.3 Individual Flow Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . 1257.3.5.4 Aggregate Flow Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . 1267.3.5.5 Port Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1277.3.5.6 Port Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1307.3.5.7 Queue Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1317.3.5.8 Queue Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1337.3.5.9 Group Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1357.3.5.10 Group Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1367.3.5.11 Group Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1377.3.5.12 Meter Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1377.3.5.13 Meter Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1387.3.5.14 Meter Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1397.3.5.15 Controller Status Multipart . . . . . . . . . . . . . . . . . . . . . . . . . 1407.3.5.16 Table Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1407.3.5.17 Table Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1407.3.5.18 Table Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1417.3.5.19 Flow Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1497.3.5.20 Bundle Features Multipart . . . . . . . . . . . . . . . . . . . . . . . . . 1557.3.5.21 Experimenter Multipart . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

7.3.6 Packet-Out Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1587.3.7 Barrier Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1607.3.8 Role Request Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1607.3.9 Bundle messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

7.3.9.1 Bundle control messages . . . . . . . . . . . . . . . . . . . . . . . . . . 1617.3.9.2 Bundle Add message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1627.3.9.3 Bundle flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1637.3.9.4 Bundle properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1637.3.9.5 Time Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1647.3.9.6 Creating and opening a bundle . . . . . . . . . . . . . . . . . . . . . . . 1657.3.9.7 Adding messages to a bundle . . . . . . . . . . . . . . . . . . . . . . . . 1657.3.9.8 Closing a bundle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1667.3.9.9 Committing Bundles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1677.3.9.10 Discarding Bundles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168



7.3.9.11 Other bundle error conditions . . . . . . . . . . . . . . . . . . . . . . . 1687.3.10 Set Asynchronous Configuration Message . . . . . . . . . . . . . . . . . . . . . . 169

7.4 Asynchronous Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1717.4.1 Packet-In Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1717.4.2 Flow Removed Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1737.4.3 Port Status Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1747.4.4 Controller Role Status Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1757.4.5 Table Status Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1767.4.6 Request Forward Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1777.4.7 Controller Status Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

7.5 Symmetric Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1787.5.1 Hello . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1787.5.2 Echo Request . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1807.5.3 Echo Reply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1807.5.4 Error Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

7.5.4.1 Hello Failed error codes . . . . . . . . . . . . . . . . . . . . . . . . . . . 1817.5.4.2 Bad Request error codes . . . . . . . . . . . . . . . . . . . . . . . . . . 1827.5.4.3 Bad Action error codes . . . . . . . . . . . . . . . . . . . . . . . . . . . 1837.5.4.4 Bad Instruction error codes . . . . . . . . . . . . . . . . . . . . . . . . . 1847.5.4.5 Bad Match error codes . . . . . . . . . . . . . . . . . . . . . . . . . . . 1857.5.4.6 Flow-mod Failed error codes . . . . . . . . . . . . . . . . . . . . . . . . 1867.5.4.7 Group-mod Failed error codes . . . . . . . . . . . . . . . . . . . . . . . 1877.5.4.8 Port-mod Failed error codes . . . . . . . . . . . . . . . . . . . . . . . . 1897.5.4.9 Table-mod Failed error codes . . . . . . . . . . . . . . . . . . . . . . . . 1907.5.4.10 Queue-op Failed error codes . . . . . . . . . . . . . . . . . . . . . . . . 1907.5.4.11 Switch Config Failed error codes . . . . . . . . . . . . . . . . . . . . . . 1907.5.4.12 Role Request Failed error codes . . . . . . . . . . . . . . . . . . . . . . 1917.5.4.13 Meter-mod Failed error codes . . . . . . . . . . . . . . . . . . . . . . . . 1917.5.4.14 Table-features Failed error codes . . . . . . . . . . . . . . . . . . . . . . 1927.5.4.15 Bad Property error codes . . . . . . . . . . . . . . . . . . . . . . . . . . 1927.5.4.16 Async Config Failed error codes . . . . . . . . . . . . . . . . . . . . . . 1937.5.4.17 Flow-monitor Failed error codes . . . . . . . . . . . . . . . . . . . . . . 1937.5.4.18 Bundle Failed error codes . . . . . . . . . . . . . . . . . . . . . . . . . . 1937.5.4.19 Experimenter Error Message . . . . . . . . . . . . . . . . . . . . . . . . 195

7.5.5 Experimenter Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

A Header file openflow.h 196

B Release Notes 238B.1 OpenFlow version 0.2.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238B.2 OpenFlow version 0.2.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238B.3 OpenFlow version 0.8.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238B.4 OpenFlow version 0.8.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239B.5 OpenFlow version 0.8.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239B.6 OpenFlow version 0.8.9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

B.6.1 IP Netmasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240B.6.2 New Physical Port Stats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240



B.6.3 IN PORT Virtual Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241B.6.4 Port and Link Status and Configuration . . . . . . . . . . . . . . . . . . . . . . . 241B.6.5 Echo Request/Reply Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241B.6.6 Vendor Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242B.6.7 Explicit Handling of IP Fragments . . . . . . . . . . . . . . . . . . . . . . . . . . 242B.6.8 802.1D Spanning Tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243B.6.9 Modify Actions in Existing Flow Entries . . . . . . . . . . . . . . . . . . . . . . . 243B.6.10 More Flexible Description of Tables . . . . . . . . . . . . . . . . . . . . . . . . . 244B.6.11 Lookup Count in Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244B.6.12 Modifying Flags in Port-Mod More Explicit . . . . . . . . . . . . . . . . . . . . . 244B.6.13 New Packet-Out Message Format . . . . . . . . . . . . . . . . . . . . . . . . . . . 244B.6.14 Hard Timeout for Flow Entries . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245B.6.15 Reworked initial handshake to support backwards compatibility . . . . . . . . . . 246B.6.16 Description of Switch Stat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246B.6.17 Variable Length and Vendor Actions . . . . . . . . . . . . . . . . . . . . . . . . . 247B.6.18 VLAN Action Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248B.6.19 Max Supported Ports Set to 65280 . . . . . . . . . . . . . . . . . . . . . . . . . . 248B.6.20 Send Error Message When Flow Not Added Due To Full Tables . . . . . . . . . . 248B.6.21 Behavior Defined When Controller Connection Lost . . . . . . . . . . . . . . . . 249B.6.22 ICMP Type and Code Fields Now Matchable . . . . . . . . . . . . . . . . . . . . 249B.6.23 Output Port Filtering for Delete*, Flow Stats and Aggregate Stats . . . . . . . . 249

B.7 OpenFlow version 0.9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250B.7.1 Failover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250B.7.2 Emergency Flow Cache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250B.7.3 Barrier Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250B.7.4 Match on VLAN Priority Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250B.7.5 Selective Flow Expirations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250B.7.6 Flow Mod Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251B.7.7 Flow Expiration Duration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251B.7.8 Notification for Flow Deletes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251B.7.9 Rewrite DSCP in IP ToS header . . . . . . . . . . . . . . . . . . . . . . . . . . . 251B.7.10 Port Enumeration now starts at 1 . . . . . . . . . . . . . . . . . . . . . . . . . . 251B.7.11 Other changes to the Specification . . . . . . . . . . . . . . . . . . . . . . . . . . 251

B.8 OpenFlow version 1.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252B.8.1 Slicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252B.8.2 Flow cookies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252B.8.3 User-specifiable datapath description . . . . . . . . . . . . . . . . . . . . . . . . . 252B.8.4 Match on IP fields in ARP packets . . . . . . . . . . . . . . . . . . . . . . . . . . 252B.8.5 Match on IP ToS/DSCP bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252B.8.6 Querying port stats for individual ports . . . . . . . . . . . . . . . . . . . . . . . 252B.8.7 Improved flow duration resolution in stats/expiry messages . . . . . . . . . . . . 253B.8.8 Other changes to the Specification . . . . . . . . . . . . . . . . . . . . . . . . . . 253

B.9 OpenFlow version 1.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253B.9.1 Multiple Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253B.9.2 Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254B.9.3 Tags : MPLS & VLAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254B.9.4 Virtual ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255



B.9.5 Controller connection failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255B.9.6 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255

B.10 OpenFlow version 1.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255B.10.1 Extensible match support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256B.10.2 Extensible set field packet rewriting support . . . . . . . . . . . . . . . . . . . . 256B.10.3 Extensible context expression in packet-in . . . . . . . . . . . . . . . . . . . . . 256B.10.4 Extensible Error messages via experimenter error type . . . . . . . . . . . . . . . 257B.10.5 IPv6 support added . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257B.10.6 Simplified behaviour of flow-mod request . . . . . . . . . . . . . . . . . . . . . . 257B.10.7 Removed packet parsing specification . . . . . . . . . . . . . . . . . . . . . . . . 257B.10.8 Controller role change mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . 257B.10.9 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258

B.11 OpenFlow version 1.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258B.11.1 Refactor capabilities negotiation . . . . . . . . . . . . . . . . . . . . . . . . . . . 258B.11.2 More flexible table miss support . . . . . . . . . . . . . . . . . . . . . . . . . . . 259B.11.3 IPv6 Extension Header handling support . . . . . . . . . . . . . . . . . . . . . . 259B.11.4 Per flow meters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259B.11.5 Per connection event filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260B.11.6 Auxiliary connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260B.11.7 MPLS BoS matching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260B.11.8 Provider Backbone Bridging tagging . . . . . . . . . . . . . . . . . . . . . . . . . 261B.11.9 Rework tag order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261B.11.10Tunnel-ID metadata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261B.11.11Cookies in packet-in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261B.11.12Duration for stats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261B.11.13On demand flow counters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262B.11.14Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262

B.12 OpenFlow version 1.3.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262B.12.1 Improved version negotiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262B.12.2 Other changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262

B.13 OpenFlow version 1.3.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263B.13.1 Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263B.13.2 Clarifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263



B.16 OpenFlow version 1.4.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266B.16.1 More extensible wire protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266B.16.2 More descriptive reasons for packet-in . . . . . . . . . . . . . . . . . . . . . . . . 267B.16.3 Optical port properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267B.16.4 Flow-removed reason for meter delete . . . . . . . . . . . . . . . . . . . . . . . . 268B.16.5 Flow monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268B.16.6 Role status events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268B.16.7 Eviction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269



B.16.8 Vacancy events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269B.16.9 Bundles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269B.16.10Synchronised tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269B.16.11Group and Meter change notifications . . . . . . . . . . . . . . . . . . . . . . . . 270B.16.12Error code for bad priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270B.16.13Error code for Set-async-config . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270B.16.14PBB UCA header field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270B.16.15Error code for duplicate instruction . . . . . . . . . . . . . . . . . . . . . . . . . 270B.16.16Error code for multipart timeout . . . . . . . . . . . . . . . . . . . . . . . . . . . 271B.16.17Change default TCP port to 6653 . . . . . . . . . . . . . . . . . . . . . . . . . . 271

B.17 OpenFlow version 1.4.1-alpha1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271B.17.1 Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271B.17.2 Clarifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271

B.18 OpenFlow version 1.5.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272B.18.1 Egress Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272B.18.2 Packet Type aware pipeline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272B.18.3 Extensible Flow Entry Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . 273B.18.4 Flow Entry Statistics Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273B.18.5 Copy-Field action to copy between two OXM fields . . . . . . . . . . . . . . . . . 273B.18.6 Packet Register pipeline fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274B.18.7 TCP flags matching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274B.18.8 Group command for selective bucket operation . . . . . . . . . . . . . . . . . . . 274B.18.9 Allow set-field action to set metadata field . . . . . . . . . . . . . . . . . . . . . . 274B.18.10Allow wildcard to be used in set-field action . . . . . . . . . . . . . . . . . . . . . 274B.18.11Scheduled Bundles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275B.18.12Controller connection status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275B.18.13Meter action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275B.18.14Enable setting all pipeline fields in packet-out . . . . . . . . . . . . . . . . . . . . 275B.18.15Port properties for pipeline fields . . . . . . . . . . . . . . . . . . . . . . . . . . . 276B.18.16Port property for recirculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276B.18.17Clarify and improve barrier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276B.18.18Always generate port status on port config change . . . . . . . . . . . . . . . . . 276B.18.19Make all Experimenter OXM-IDs 64 bits . . . . . . . . . . . . . . . . . . . . . . 276B.18.20Unified requests for group, port and queue multiparts . . . . . . . . . . . . . . . 277B.18.21Rename some type for consistency . . . . . . . . . . . . . . . . . . . . . . . . . . 277B.18.22Specification reorganisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

C Credits 277

List of Tables1 Main components of a flow entry in a flow table. . . . . . . . . . . . . . . . . . . . . . . 222 Push/pop tag actions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 Change-TTL actions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304 Existing fields that may be copied into new fields on a push action. . . . . . . . . . . . . 305 List of counters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32



6 Main components of a group entry in the group table. . . . . . . . . . . . . . . . . . . . 337 Main components of a meter entry in the meter table. . . . . . . . . . . . . . . . . . . . 348 Main components of a meter band in a meter entry. . . . . . . . . . . . . . . . . . . . . 349 Common Canonical Header Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7010 OXM TLV header fields. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7211 OXM mask and value. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7312 Required match fields. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7613 Header match fields details. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7814 Match combinations for VLAN tags. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7915 Pipeline match fields details. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8016 Packet Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8217 OXS TLV header fields. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8418 Stat fields details. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

List of Figures1 Main components of an OpenFlow switch. . . . . . . . . . . . . . . . . . . . . . . . . . . 112 Packet flow through the processing pipeline. . . . . . . . . . . . . . . . . . . . . . . . . . 193 Simplified flowchart detailing packet flow through an OpenFlow switch. . . . . . . . . . 234 Matching and Instruction exectution in a flow table. . . . . . . . . . . . . . . . . . . . . 255 Scheduled Bundle Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 576 Discarding a Scheduled Commit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587 Scheduling Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 598 OXM TLV header layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 719 OXS TLV header layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84



1 Introduction

This document describes the requirements of an OpenFlow Logical Switch. Additional informationdescribing OpenFlow and Software Defined Networking is available on the Open Networking Foundationwebsite (https://www.opennetworking.org/). This specification covers the components and the basicfunctions of the switch, and the OpenFlow switch protocol to manage an OpenFlow switch from aremote OpenFlow controller.

Port

Port

Port

Port

OpenFlowChannel

FlowTable

FlowTable

FlowTable

Controller

Pipeline

OpenFlow Switch

OpenFlowChannel Group

TableMeterTableControl Channel

Controller

Datapath

Protocol

Figure 1: Main components of an OpenFlow switch.

2 Switch Components

An OpenFlow Logical Switch consists of one or more flow tables and a group table, which perform packetlookups and forwarding, and one or more OpenFlow channels to an external controller (Figure 1). Theswitch communicates with the controller and the controller manages the switch via the OpenFlow switchprotocol.

Using the OpenFlow switch protocol, the controller can add, update, and delete flow entries in flowtables, both reactively (in response to packets) and proactively. Each flow table in the switch containsa set of flow entries; each flow entry consists of match fields, counters, and a set of instructions to applyto matching packets (see 5.2).

Matching starts at the first flow table and may continue to additional flow tables of the pipeline (see5.1). Flow entries match packets in priority order, with the first matching entry in each table beingused (see 5.3). If a matching entry is found, the instructions associated with the specific flow entry areexecuted (see 5.5). If no match is found in a flow table, the outcome depends on configuration of the


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table-miss flow entry: for example, the packet may be forwarded to the controllers over the OpenFlowchannel, dropped, or may continue to the next flow table (see 5.4).

Instructions associated with each flow entry either contain actions or modify pipeline processing (see5.5). Actions included in instructions describe packet forwarding, packet modification and group tableprocessing. Pipeline processing instructions allow packets to be sent to subsequent tables for furtherprocessing and allow information, in the form of metadata, to be communicated between tables. Tablepipeline processing stops when the instruction set associated with a matching flow entry does not specifya next table; at this point the packet is usually modified and forwarded (see 5.6).

Flow entries may forward to a port. This is usually a physical port, but it may also be a logical portdefined by the switch or a reserved port defined by this specification (see 4.1). Reserved ports mayspecify generic forwarding actions such as sending to the controller, flooding, or forwarding using non-OpenFlow methods, such as normal switch processing (see 4.5), while switch-defined logical portsmay specify link aggregation groups, tunnels or loopback interfaces (see 4.4).

Actions associated with flow entries may also direct packets to a group, which specifies additionalprocessing (see 5.10). Groups represent sets of actions for flooding, as well as more complex forwardingsemantics (e.g. multipath, fast reroute, and link aggregation). As a general layer of indirection, groupsalso enable multiple flow entries to forward to a single identifier (e.g. IP forwarding to a common nexthop). This abstraction allows common output actions across flow entries to be changed efficiently.

The group table contains group entries; each group entry contains a list of action buckets with specificsemantics dependent on group type (see 5.10.1). The actions in one or more action buckets are appliedto packets sent to the group.

Switch designers are free to implement the internals in any way convenient, provided that correct matchand instruction semantics are preserved. For example, while a flow entry may use an all group toforward to multiple ports, a switch designer may choose to implement this as a single bitmask withinthe hardware forwarding table. Another example is matching; the pipeline exposed by an OpenFlowswitch may be physically implemented with a different number of hardware tables.

3 Glossary

This section describes key OpenFlow specification terms. Most terms are specific to this specification.

Action: an operation that forwards the packet to a port, modifies the packet (such as decre-menting the TTL field) or changes its state (such as associating it with a queue). Most actionsinclude parameters, for example a set-field action includes a field type and field value. Actionsmay be specified as part of the instruction set associated with a flow entry or in an action bucketassociated with a group entry. Actions may be accumulated in the Action Set of the packet orapplied immediately to the packet (see 5.8).

List of Actions: a list of actions included in a flow entry in the Apply-Actions instruction or ina packet-out message that are executed immediately in the list order (see 5.7). Actions in a listcan be duplicated, their effects are cumulative.



Set of Actions: a set of actions included in a flow entry in the Write-Actions instruction thatare added to the action set, or in a group action-bucket that are executed in action-set order (see5.6). Actions in a set can occur only once.

Action Bucket: a set of actions in a group. The group will select one or more buckets for eachpacket.

Action Set: a set of actions associated with the packet that are accumulated while the packet isprocessed by each table and that are executed in specified order when the instruction set terminatespipeline processing (see 5.6).

Byte: an 8-bit octet.

Connection: a network connection that carry OpenFlow messages between a switch and a con-troller, it may be implemented using various network transport protocols (see 6.3). An OpenFlowchannel has a main connection, and optionally a number of auxiliary connections (see 6.3.7).

Control Channel: The aggregation of components of an OpenFlow logical switch that man-age communication with controllers. The control channel includes one OpenFlow channel perOpenFlow controller.

Controller: see OpenFlow controller.

Counter: counters are the main element of OpenFlow statistics and accumulated at variousspecific points of the pipeline, such as on a port or on a flow entry (see 5.9). Counters typicallycount the number of packets and bytes passing through an OpenFlow element, however othercounters types are also defined.

Datapath: the aggregation of components of an OpenFlow logical switch that are directly in-volved in traffic processing and forwarding. The datapath includes the pipeline of flow tables, thegroup table and the ports.

Flow Entry: an element in a flow table used to match and process packets. It contains a set ofmatch fields for matching packets, a priority for matching precedence, a set of counters to trackpackets, and a set of instructions to apply (see 5.2).

Flow Table: a stage of the pipeline. It contains flow entries.

Forwarding: Deciding the output port or set of output ports for a packet, and transfering thatpacket to those output ports.

Group: a list of action buckets and some means of choosing one or more of those buckets to applyon a per-packet basis (see 5.10).

Header: control information embedded in a packet used by a switch to identify the packet andto inform the switch on how to process and forward the packet. The header typically includesvarious header fields to identify the source and destination of the packet, and how to interpretother headers and the payload.

Header Field: a value from the packet header. The packet header is parsed to extract its headerfields which are matched against corresponding match fields.

Hybrid: integrate both OpenFlow operation and normal Ethernet switching operation (see 5.1).



Instruction: instructions are attached to a flow entry and describe the OpenFlow processing thathappens when a packet matches the flow entry. An instruction either modifies pipeline processing,such as directing the packet to another flow table, or contains a set of actions to add to the actionset, or contains a list of actions to apply immediately to the packet (see 5.5).

Instruction Set: a set of instructions attached to a flow entry in a flow table.

Match Field: a part of a flow entry against which a packet is matched. Match fields can matchthe various packet header fields (see 7.2.3.8), the packet ingress port, the metadata value andother pipeline fields (see 7.2.3.9). A match field may be wildcarded (match any value) and insome cases bitmasked (match subset of bits).

Matching: comparing the set of header fields and pipeline fields of a packet to the match fieldsof a flow entry (see 5.3).

Metadata: a maskable register that is used to carry information from one table to the next.

Message: OpenFlow protocol unit sent over an OpenFlow connection. May be a request, a reply,a control message or a status event.

Meter: a switch element that can measure and control the rate of packets. The meter triggersa meter band if the packet rate or byte rate passing through the meter exceeds a predefinedthreshold (see 5.11). If the meter band drops the packet, it is called a Rate Limiter.

OpenFlow Channel: interface between an OpenFlow switch and an OpenFlow controller, usedby the controller to manage the switch.

OpenFlow Controller: an entity interacting with the OpenFlow switch using the OpenFlowswitch protocol. In most case, an OpenFlow Controller is software which controls many OpenFlowLogical Switches.

OpenFlow Logical Switch: A set of OpenFlow resources that can be managed as a single entity,includes a datapath and a control channel.

OpenFlow Protocol: The protocol defined by this specification. Also called OpenFlow SwitchProtocol.

OpenFlow Switch: See OpenFlow Logical Switch.

Packet: a series of bytes comprising a header, a payload and optionally a trailer, in that order,and treated as a unit for purposes of processing and forwarding. The default packet type isEthernet, other packet types are also supported (see 7.2.3.11).

Pipeline: the set of linked flow tables that provide matching, forwarding, and packet modificationin an OpenFlow switch (see 5.1).

Pipeline fields: set of values attached to the packet during pipeline processing which are notheader fields. Include the ingress port, the metadata value, the Tunnel-ID value and others (see7.2.3.9).

Port: where packets enter and exit the OpenFlow pipeline (see 4.1). May be a physical port, alogical port, or a reserved port defined by the OpenFlow switch protocol.

Queue: Schedule packets according to their priority on an output port to provide Quality-of-Service (QoS).



Switch: See OpenFlow Logical Switch.

Tag: a header that can be inserted or removed from a packet via push and pop actions.

Outermost Tag: the tag that appears closest to the beginning of a packet.

4 OpenFlow Ports

This section describes the OpenFlow port abstraction and the various types of OpenFlow ports sup-ported by OpenFlow.

4.1 OpenFlow Ports

OpenFlow ports are the network interfaces for passing packets between OpenFlow processing and therest of the network. OpenFlow switches connect logically to each other via their OpenFlow ports, apacket can be forwarded from one OpenFlow switch to another OpenFlow switch only via an outputOpenFlow port on the first switch and an ingress OpenFlow port on the second switch.

An OpenFlow switch makes a number of OpenFlow ports available for OpenFlow processing. The set ofOpenFlow ports may not be identical to the set of network interfaces provided by the switch hardware,some network interfaces may be disabled for OpenFlow, and the OpenFlow switch may define additionalOpenFlow ports.

OpenFlow packets are received on an ingress port and processed by the OpenFlow pipeline (see 5.1)which may forward them to an output port. The packet ingress port is a property of the packetthroughout the OpenFlow pipeline and represents the OpenFlow port on which the packet was receivedinto the OpenFlow switch. The ingress port can be used when matching packets (see 5.3). The Open-Flow pipeline can decide to send the packet on an output port using the output action (see 5.8), whichdefines how the packet goes back to the network.

An OpenFlow switch must support three types of OpenFlow ports: physical ports, logical ports andreserved ports.

4.2 Standard Ports

The OpenFlow standard ports are defined as physical ports, logical ports, and the LOCAL reservedport if supported (excluding other reserved ports).

Standard ports can be used as ingress and output ports, they can be used in groups (see 5.10), theyhave port counters (see 5.9) and they have state and configuration (see 7.2.1).



4.3 Physical Ports

The OpenFlow physical ports are switch defined ports that correspond to a hardware interface of theswitch. For example, on an Ethernet switch, physical ports map one-to-one to the Ethernet interfaces.

In some deployments, the OpenFlow switch may be virtualised over the switch hardware. In those cases,an OpenFlow physical port may represent a virtual slice of the corresponding hardware interface of theswitch.

4.4 Logical Ports

The OpenFlow logical ports are switch defined ports that dont correspond directly to a hardwareinterface of the switch. Logical ports are higher level abstractions that may be defined in the switchusing non-OpenFlow methods (e.g. link aggregation groups, tunnels, loopback interfaces).

Logical ports may include packet encapsulation and may map to various physical ports. The processingdone by the logical port is implementation dependant and must be transparent to OpenFlow processing,and those ports must interact with OpenFlow processing like OpenFlow physical ports.

The only differences between physical ports and logical ports is that a packet associated with a logicalport may have an extra pipeline field called Tunnel-ID associated with it (see 7.2.3.9) and when a packetreceived on a logical port is sent to the controller, both its logical port and its underlying physical portare reported to the controller (see 7.4.1).

4.5 Reserved Ports

The OpenFlow reserved ports are defined by this specification. They specify generic forwardingactions such as sending to the controller, flooding, or forwarding using non-OpenFlow methods, suchas normal switch processing.

A switch is not required to support all reserved ports, just those marked Required below.

Required: ALL: Represents all ports the switch can use for forwarding a specific packet. Canbe used only as an output port. In that case a copy of the packet starts egress processing on allstandard ports, excluding the packet ingress port and ports that are configured OFPPC_NO_FWD.

Required: CONTROLLER: Represents the control channel with the OpenFlow controllers. Canbe used as an ingress port or as an output port. When used as an output port, encapsulate thepacket in a packet-in message and send it using the OpenFlow switch protocol (see 7.4.1). Whenused as an ingress port, this identifies a packet originating from the controller.

Required: TABLE: Represents the start of the OpenFlow pipeline (see 5.1). This port is onlyvalid in an output action in the list of actions of a packet-out message (see 7.3.6), and submits thepacket to the first flow table so that the packet can be processed through the regular OpenFlowpipeline.

Required: IN PORT: Represents the packet ingress port. Can be used only as an output port,send the packet out through its ingress port.



Required: ANY: Special value used in some OpenFlow requests when no port is specified (i.e. portis wildcarded). Some OpenFlow requests contain a reference to a specific port that the requestonly applies to. Using ANY as the port number in these requests allows that request instance toapply to any and all ports. Can neither be used as an ingress port nor as an output port.

Required: UNSET: Special value to specify the that output port has not been set in theAction-Set. Only used when trying to match the output port in the action set using theOXM_OF_ACTSET_OUTPUT match field (see 7.2.3.7). Can neither be used as an ingress port noras an output port.

Optional: LOCAL: Represents the switchs local networking stack and its management stack.Can be used as an ingress port or as an output port. The local port enables remote entities tointeract with the switch and its network services via the OpenFlow network, rather than via aseparate control network. With a suitable set of default flow entries it can be used to implementan in-band controller connection.

Optional: NORMAL: Represents forwarding using the traditional non-OpenFlow pipeline of theswitch (see 5.1). Can be used only as an output port and processes the packet using the normalpipeline. In general will bridge or route the packet, however the actual result is implementationdependant. If the switch cannot forward packets from the OpenFlow pipeline to the normalpipeline, it must indicate that it does not support this action.

Optional: FLOOD: Represents flooding using the traditional non-OpenFlow pipeline of the switch(see 5.1). Can be used only as an output port, actual result is implementation dependant. Ingeneral will send the packet out all standard ports, but not to the ingress port, nor ports that arein OFPPS_BLOCKED state. The switch may also use the packet VLAN ID or other criteria to selectwhich ports to use for flooding.

OpenFlow-only switches do not support the NORMAL port and FLOOD port, while OpenFlow-hybridswitches may support them (see 5.1). Forwarding packets to the FLOOD port depends on the switchimplementation and configuration, while forwarding using a group of type all enables the controller tomore flexibly implement flooding (see 5.10.1).

4.6 Port changes

A switch configuration, for example using the OpenFlow Configuration Protocol, may add or removeports from the OpenFlow switch at any time. The switch may change the port state based on theunderlying port mechanism, for example if the link is going down (see 7.2.1). The controller or aswitch configuration may change the port configuration (see 7.2.1). Any such changes to port state orconfiguration must be communicated to the OpenFlow controller (see 7.4.3).

Port addition, modification or removal never changes the content of the flow tables, in particular flowentries referencing those ports are not modified or removed (flow entries may reference ports via thematch or actions). Packet forwarded to non-existent ports are just dropped (see 5.6). Similarly, Portaddition, modification and removal never changes the content of the group table, however the behaviourof some groups may change through liveness checking (see 6.7).

If a port is deleted and its port number is later reused for a different physical or logical port, anyremaining flow entries or group entries still referencing that port number may be effectively re-targeted



to the new port, possibly with undesirable results. Therefore, when a port is deleted it is left to thecontroller to clean up any flow entries or group entries referencing that port, if needed.

4.7 Port recirculation

Logical ports can optionally be used to insert a network service or complex processing in the OpenFlowswitch (see 4.4). Most often, packets sent to logical ports never return to the same OpenFlow switch,they are either consumed by the logical port or eventually sent over a physical port. In other cases,packets sent to a logical port are recirculated back to the OpenFlow switch after the logical portprocessing.

Packet recirculation via logical ports is optional, and OpenFlow supports multiple types of port re-circulation. The simplest recirculation is when a packet sent on a logical port returns back into theswitch via the same logical port. This could be used for a loopback or unidirectional packet processing.Recirculation can also happen between a port pair, in which a packet sent on a logical port returns backinto the switch via the other logical port of the pair. This could be used to represent tunnel endpoints orbidirectional packet processing. A port property describes the recirculation relationship between ports(see 7.2.1.2).

A switch should protect itself from packet infinite loops when using port recirculation. This mechanismis implementation-specific and outside the scope of this specification. For example, the switch couldattach an internal recirculation count to each packet, which is incremented for each recirculation, and theswitch drops packets for which the counter is above a switch-defined threshold. Controllers are stronglyencouraged to avoid generating combinations of flow entries that may yield recirculation loops.

Because of the wide range of possible processing, very little can be assumed about the packets recircu-lated back into the switch. Recirculated packets go back to the first flow table of the pipeline (see 5.1)and can be identified by their new input port. The packet headers may have changed, so the matchfields are not guaranteed to be the same. The logical port may do packet fragmentation and reassembly,so the packets may not match one to one and may have different sizes.

The Tunnel-ID field and some other pipeline fields associated with the packet may optionally bepreserved through the recirculation and available for matching when returning to the switch, thepipeline fields that are preserved are indicated via the port match field property (see 7.2.1.2). If apipeline field is present in both the OFPPDPT_PIPELINE_OUTPUT property of the output port and theOFPPDPT_PIPELINE_INPUT property of the return port, then this pipeline field is preserved with thepacket (its value must remain the same).

5 OpenFlow Tables

This section describes the components of flow tables and group tables, along with the mechanics ofmatching and action handling.



IngressPort

Packet +pipeline fields(ingress port,metadata...)Flow

Table0

FlowTable

1

FlowTable

n

ExecuteAction

SetActionSet

ActionSet = {}

Ingress processingSet

IngressPort Group

Table

Packet +pipeline fields

(output port,metadata...)Flow

Tablee

FlowTablee+1

FlowTablee+m

ExecuteAction

SetActionSet

ActionSet =

{output}

Egress processingSet

OutputPort Output

Port

PacketIn

PacketOut

e = first egress table-id

Figure 2: Packet flow through the processing pipeline.

5.1 Pipeline Processing

OpenFlow-compliant switches come in two types: OpenFlow-only, and OpenFlow-hybrid. OpenFlow-only switches support only OpenFlow operation, in those switches all packets are processed by theOpenFlow pipeline, and can not be processed otherwise.

OpenFlow-hybrid switches support both OpenFlow operation and normal Ethernet switching opera-tion, i.e. traditional L2 Ethernet switching, VLAN isolation, L3 routing (IPv4 routing, IPv6 routing...),ACL and QoS processing. Those switches should provide a classification mechanism outside of Open-Flow that routes traffic to either the OpenFlow pipeline or the normal pipeline. For example, a switchmay use the VLAN tag or input port of the packet to decide whether to process the packet using onepipeline or the other, or it may direct all packets to the OpenFlow pipeline. This classification mech-anism is outside the scope of this specification. An OpenFlow-hybrid switch may also allow a packetto go from the OpenFlow pipeline to the normal pipeline through the NORMAL and FLOOD reservedports (see 4.5).

The OpenFlow pipeline of every OpenFlow Logical Switch contains one or more flow tables, each flowtable containing multiple flow entries. The OpenFlow pipeline processing defines how packets interactwith those flow tables (see Figure 2). An OpenFlow switch is required to have at least one ingress flowtable, and can optionally have more flow tables. An OpenFlow switch with only a single flow table isvalid, in this case pipeline processing is greatly simplified.

The flow tables of an OpenFlow switch are sequentially numbered, starting at 0. Pipeline processing



happens in two stages, ingress processing and egress processing. The separation of the two stages isindicated by the first egress table (see 7.3.2), all tables with a number lower than the first egress tablemust be used as ingress tables, and no table with a number higher than or equal to the first egress tablecan be used as an ingress table.

Pipeline processing always starts with ingress processing at the first flow table: the packet must befirst matched against flow entries of flow table 0 (see Figure 3). Other ingress flow tables may beused depending on the outcome of the match in the first table. If the outcome of ingress processing isto forward the packet to an output port, the OpenFlow switch may perform egress processing in thecontext of that output port. Egress processing is optional, a switch may not support any egress tablesor may not be configured to use them. If no valid egress table is configured as the first egress table (see7.3.2), the packet must be process by the output port, and in most case the packet is forwarded out ofthe switch. If a valid egress table is configured as the first egress table (see 7.3.2), the packet must bematched against flow entries of that flow table, and other egress flow tables may be used depending onthe outcome of the match in that flow table.

When processed by a flow table, the packet is matched against the flow entries of the flow table toselect a flow entry (see 5.3). If a flow entry is found, the instruction set included in that flow entry isexecuted. These instructions may explicitly direct the packet to another flow table (using the Goto-Table Instruction, see 5.5), where the same process is repeated again. A flow entry can only direct apacket to a flow table number which is greater than its own flow table number, in other words pipelineprocessing can only go forward and not backward. Obviously, the flow entries of the last table of apipeline stage can not include the Goto-Table instruction. If the matching flow entry does not directpackets to another flow table, the current stage of pipeline processing stops at this table, the packet isprocessed with its associated action set and usually forwarded (see 5.6).

If a packet does not match a flow entry in a flow table, this is a table miss. The behavior on a table missdepends on the table configuration (see 5.4). The instructions included in the table-miss flow entry inthe flow table can flexibly specify how to process unmatched packets, useful options include droppingthem, passing them to another table or sending them to the controllers over the control channel viapacket-in messages (see 6.1.2).

There are few cases where a packet is not fully processed by a flow entry and pipeline processing stopswithout processing the packets action set or directing it to another table. If no table-miss flow entryis present, the packet is dropped (see 5.4). If an invalid TTL is found, the packet may be sent to thecontroller (see 5.8).

The OpenFlow pipeline and various OpenFlow operations process packets of a specific type in con-formance with the specifications defined for that packet type, unless the present specification or theOpenFlow configuration specify otherwise. For example, the Ethernet header definition used by Open-Flow must conform to IEEE specifications, and the TCP/IP header definition used by OpenFlow mustconform to RFC specifications. Additionally, packet reordering in an OpenFlow switch must conformto the requirements of IEEE specifications, provided that the packets are processed by the same flowentries, group buckets and meter bands.



5.1.1 Pipeline Consistency

The OpenFlow pipeline is an abstraction that is mapped to the actual hardware of the switch. In somecases, the OpenFlow switch is virtualised on the hardware, for example to support multiple OpenFlowswitch instances or in the case of an hybrid switch. Even if the OpenFlow switch is not virtualised,the hardware typically will not correspond to the OpenFlow pipeline, for example if a flow table onlysupports Ethernet packets, non-Ethernet packets would have to be mapped to Ethernet. In anotherexample some switches may carry VLAN information in some internal metadata while for the OpenFlowpipeline it is logically part of the packet. Some OpenFlow switches may define logical ports implementingcomplex encapsulations that extensively modify the packet headers. The consequence is that a packeton a link or in hardware may be mapped differently in the OpenFlow pipeline.

However, the OpenFlow pipeline expects that the mapping to the hardware is consistent, and that theOpenFlow pipeline behaves consistently. In particular, this is what is expected :

Tables consistency: the packet must match in the same way in all the OpenFlow flow tables,and the only difference in matching must be due to the flow table content and explicit OpenFlowprocessing done by those flow tables. In particular, headers can not be transparently removed,added or changed between tables, unless explicitly specified by OpenFlow processing.

Flow entry consistency: the way the actions of a flow entry apply to a packet must be consistentwith the flow entry match. In particular, if a match field in the flow entry matches a specific packetheader field, the corresponding set-field action in the flow entry must modify the same header field,unless explicit OpenFlow processing has modified the packet.

Group consistency: the application of groups must be consistent with flow tables. In particular,actions of a group bucket must apply to the packet the same way as if they were in a flow table,the only difference must be due to explicit OpenFlow processing.

Packet-in consistency: the packet embedded in the packet-in messages must be consistent withthe OpenFlow flow tables. In particular, if the packet-in was generated directly by a flow entry,the packet received by the controller must match the flow entry that sent it to the controller.

Packet-out consistency: the packet generated as the result of a packet-out request must beconsistent with the OpenFlow flow tables and the packet-in process. In particular, if a packetreceived via a packet-in is is sent directly without modifications out a port via a packet-out, thepacket on that port must be identical, as if the packet had been sent to that port instead ofencapsulated in a packet-in. Similarly, if a packet-out is directed at flow tables, the flow entriesmust match the encapsulated packet as expected by the OpenFlow matching process.

Port consistency: the ingress and egress processing of an OpenFlow port must be consistentwith each other. In particular, if an OpenFlow packet is output on a port and generates a physicalpacket on a switch physical link, then if the reception by the switch of the same physical packeton the same link generates an OpenFlow packet on the same port, the OpenFlow packet must beidentical.



5.2 Flow Tables and flow entries

A flow table consists of flow entries.

Match Fields Priority Counters Instructions Timeouts Cookie Flags

Table 1: Main components of a flow entry in a flow table.

Each flow table entry (see Table 1) contains :

match fields: to match against packets. These consist of the ingress port and packet headers,and optionally other pipeline fields such as metadata specified by a previous table.

priority: matching precedence of the flow entry.

counters: updated when packets are matched.

instructions: to modify the action set or pipeline processing.

timeouts: maximum amount of time or idle time before flow is expired by the switch.

cookie: opaque data value chosen by the controller. May be used by the controller to filter flowentries affected by flow statistics, flow modification and flow deletion requests. Not used whenprocessing packets.

flags: flags alter the way flow entries are managed, for example the flag OFPFF_SEND_FLOW_REMtriggers flow removed messages for that flow entry.

A flow table entry is identified by its match fields and priority: the match fields and priority takentogether identify a unique flow entry in a specific flow table. The flow entry that wildcards all fields(all fields omitted) and has priority equal to 0 is called the table-miss flow entry (see 5.4).

A flow entry instruction may contain actions to be performed on the packet at some point of the pipeline(see 5.8). The set-field action may specify some header fields to rewrite. Each flow table may not supportevery match field, every instruction, every action or every set-field defined by this specification, anddifferent flow tables of the switch may not support the same subset. The table features request enablesthe controller to discover what each table supports (see 7.3.5.18).

5.3 Matching

On receipt of a packet, an OpenFlow Switch performs the functions shown in Figure 3. The switch startsby performing a table lookup in the first flow table, and based on pipeline processing, may performtable lookups in other flow tables (see 5.1).

Packet match fields are extracted from the packet. Packet match fields used for table lookups dependon the packet type, and typically include various packet header fields, such as Ethernet source addressor IPv4 destination address (see 7.2.3). In addition to packet headers, matches can also be performedagainst the ingress port, the metadata field and other pipeline fields. Metadata may be used to passinformation between tables in a switch. The packet match fields represent the packet in its current state,if actions applied in a previous table using the Apply-Actions instruction changed the packet headers,those changes are reflected in the packet match fields.



Groupaction ?

Outputaction ?

Yes

NoDrop packet

Start egress processing action set = {output port} start at first egress table

Match intable n ?

Packet In clear action set initialise pipeline fields start at table 0

Execute action set : update packet headers update match set fields update pipeline fields

Goto-Table n ?

Table-miss flow

entryexists ?

Drop packet

No

No

Yes

Yes

Yes

No

Yes

Outputaction ?

Yes

No

Packet Out

No

Drop packet

Yes No

Match intable n ?

Goto-Table n ?

Table-miss flow

entryexists ?

Drop packet

No

No

Yes

Yes

Yes

No

Drop packetDrop packetDrop packet

switchhas egress

tables ?

switchhas egress

tables ?

Update countersExecute instruction set : update action set update packet headers update match set fields update pipeline fields as needed, clone packet to egress



Update countersExecute instruction set : update action set update packet headers update match set fields update pipeline fields as needed, clone packet to egress

IngressEgress

Figure 3: Simplified flowchart detailing packet flow through an OpenFlow switch.



A packet matches a flow table entry if the values in the packet match fields used for the lookup matchthose defined in the flow table entry. If a flow table entry field has a value of ANY (field omitted), itmatches all possible values in the header. If the switch supports arbitrary bitmasks on specific matchfields, these masks can more precisely specify matches.

The packet is matched against the table and only the highest priority flow entry that matches thepacket must be selected. The counters associated with the selected flow entry must be updated and theinstruction set included in the selected flow entry must be applied. If there are multiple matching flowentries with the same highest priority, the selected flow entry is explicitly undefined. This case can onlyarise when a controller writer never sets the OFPFF_CHECK_OVERLAP bit on flow mod messages and addsoverlapping entries.

IP fragments must be reassembled before pipeline processing if the switch configuration contains theOFPC_FRAG_REASM flag (see 7.3.2).

This version of the specification does not define the expected behavior when a switch receives a mal-formed or corrupted packet.

5.4 Table-miss

Every flow table must support a table-miss flow entry to process table misses. The table-miss flow entryspecifies how to process packets unmatched by other flow entries in the flow table (see 5.1), and may,for example, send packets to the controller, drop packets or direct packets to a subsequent table.

The table-miss flow entry is identified by its match and its priority (see 5.2), it wildcards all matchfields (all fields omitted) and has the lowest priority (0). The match of the table-miss flow entrymay fall outside the normal range of matches supported by a flow table, for example an exact matchtable would not support wildcards for other flow entries but must support the table-miss flow entrywildcarding all fields. The table-miss flow entry may not have the same capability as regular flow entry(see 7.3.5.18). The table-miss flow entry must support at least sending packets to the controller usingthe CONTROLLER reserved port (see 4.5) and dropping packets using the Clear-Actions instruction(see 5.5). Implementations are encouraged to support directing packets to a subsequent table whenpossible for compatibility with earlier versions of this specification.

The table-miss flow entry behaves in most ways like any other flow entry: it does not exist by default ina flow table, the controller may add it or remove it at any time (see 6.4), and it may expire (see 6.5). Thetable-miss flow entry matches packets in the table as expected from its set of match fields and priority(see 5.3): it matches packets unmatched by other flow entries in the flow table. The table-miss flowentry instructions are applied to packets matching the table-miss flow entry (see 5.5). If the table-missflow entry directly sends packets to the controller using the CONTROLLER reserved port (see 4.5), thepacket-in reason must identify a table-miss (see 7.4.1).

If the table-miss flow entry does not exist, by default packets unmatched by flow entries are dropped(discarded). A switch configuration, for example using the OpenFlow Configuration Protocol, mayoverride this default and specify another behaviour.



Match

Find highestprioritymatchingflow entry

Apply-actions{list of actions} modify packet update match fields update pipeline fields if output or group clone packet

Clear-actions empty action setWrite-actions{set of actions} merge in action set

Goto-table{table-id}

Extractheaderfields

Apply Instructions

Flow Table

Packet

ActionSet

PipelineFields

EgressPacket clones

ExecuteActionSet

FlowTable

flow entry

flow entryflow entry

flow entry

flow entrytable missflow entry

Figure 4: Matching and Instruction exectution in a flow table.

5.5 Instructions

Each flow entry contains a set of instructions that are executed when a packet matches the entry. Theseinstructions result in changes to the packet, action set and/or pipeline processing (see Figure 4).

A switch is not required to support all instruction types, just those marked Required Instructionbelow. The controller can also query the switch about which of the Optional Instruction types itsupports.

Optional Instruction: Apply-Actions action(s): Applies the specific action(s) immediately,without any change to the Action Set. This instruction may be used to modify the packet betweentwo tables or to execute multiple actions of the same type. The actions are specified as a list ofactions (see 5.7).

Optional Instruction: Clear-Actions: Clears all the actions in the action set immediately.

Required Instruction: Write-Actions action(s): Merges the specified set of action(s) into thecurrent action set (see 5.6). If an action of the given type exists in the current set, overwrite it,otherwise add it. If a set-field action with a given field type exists in the current set, overwrite it,otherwise add it.

Optional Instruction: Write-Metadata metadata / mask: Writes the masked metadata valueinto the metadata field. The mask specifies which bits of the metadata register should be modified(i.e. new metadata = old metadata & mask | value & mask).



Optional Instruction: Stat-Trigger stat thresholds: Generate an event to the controller if someof the flow statistics cross one of the stat threshold values.

Required Instruction: Goto-Table next-table-id: Indicates the next table in the processingpipeline. The table-id must be greater than the current table-id. The flow entries of the last tableof the pipeline can not include this instruction (see 5.1). OpenFlow switches with only a singleflow table are not required to implement this instruction.

The instruction set associated with a flow entry contains a maximum of one instruction of each type.The experimenter instructions are identified by their experimenter-id and experimenter-type, thereforethe instruction set may contain a maximum of one experimenter instruction for each combination ofexperimenter-id and experimenter-type. The instructions of the set execute in the order specified bythis above list. In practice, the only constraints are that the Clear-Actions instruction is executedbefore the Write-Actions instruction, the Apply-Actions is executed before the Write-Metadata andthat Goto-Table is executed last.

A switch must reject a flow entry if it is unable to execute the instructions or part of the instructionsassociated with the flow entry. In this case, the switch must return the error message associated withthe issue (see 7.5.4.4).

5.6 Action Set

An action set is associated with each packet. This set is empty by default. A flow entry can modify theaction set using a Write-Action instruction or a Clear-Action instruction associated with a particularmatch. The action set is carried between flow tables. When the instruction set of a flow entry doesnot contain a Goto-Table instruction, pipeline processing stops and the actions in the action set of thepacket are executed (see Figure 3).

An action set contains a maximum of one action of each type. The set-field actions are identified by theirdestination field types, therefore the action set contains a maximum of one set-field action for each fieldtype (i.e. multiple fields can be set, but each field can only be set once). The effect of copy-field actionsin the action set is undefined due to race conditions, and therefore its implementation discouraged. Theexperimenter actions are identified by their experimenter-id and experimenter-type, therefore the actionset may contain a maximum of one experimenter action for each combination of experimenter-id andexperimenter-type. When an action of a specific type is added in the action set, if an action of the sametype exist, it is overwritten by the later action. If multiple actions of the same type are required, e.g.pushing multiple MPLS labels or popping multiple MPLS labels, the Apply-Actions instruction shouldbe used (see 5.7).

The action set for egress processing has one restriction, both the output action and the group action cannot be added to the egress action-set. The action set for egress processing is initialised at the beginningof egress processing with an output action for the current output port, whereas the action set for ingressprocessing starts empty.

The actions in an action set are applied in the order specified below, regardless of the order that theywere added to the set. If an action set contains a group action, the actions in the appropriate actionbucket(s) of the group are also applied in the order specified below. The switch may support arbitraryaction execution order through the list of actions of the Apply-Actions instruction.



1. copy TTL inwards: apply copy TTL inward actions to the packet

2. pop: apply all tag pop actions to the packet

3. push-MPLS: apply MPLS tag push action to the packet

4. push-PBB: apply PBB tag push action to the packet

5. push-VLAN: apply VLAN tag push action to the packet

6. copy TTL outwards: apply copy TTL outwards action to the packet

7. decrement TTL: apply decrement TTL action to the packet

8. set: apply all set-field actions to the packet

9. qos: apply all QoS actions, such as meter and set queue to the packet

10. group: if a group action is specified, apply the actions of the relevant group bucket(s) in theorder specified by this list

11. output: if no group action is specified, forward the packet on the port specified by the outputaction

The output action in the action set is executed last. If both an output action and a group action arespecified in an action set, the output action is ignored and the group action takes precedence. If nooutput action and no group action were specified in an action set, the packet is dropped. If no groupaction is specified and the output action references an non-existent port, the packet is dropped. Theexecution of groups is recursive if the switch supports it; a group bucket may specify another group, inwhich case the execution of actions traverses all the groups specified by the group configuration.

The output action is processed differently in ingress and egress (see 5.1). When the ingress action setcontains an output action or a group action forwarding the packet to a port, the packet must startegress processing on that port (see 5.1). If the output action references the ALL reserved port, a clone(copy) of the packet start egress processing for each relevant port (see 4.5). When the egress action setcontains an output action, the packet must exit egress processing and must be processed by the port,and in most cases it is forwarded out of the switch.

5.7 List of Actions

The Apply-Actions instruction and the Packet-out message include a list of actions. The semantics ofthe list of actions is identical to the OpenFlow 1.0 specification. The actions of a list of actions areexecuted in the order specified by the list, and are applied immediately to the packet.

The execution of a list of actions starts with the first action in the list and each action is executed onthe packet in sequence. The effect of those actions is cumulative, if the list of actions contains two PushVLAN actions, two VLAN headers are added to the packet.

If the list of actions contains an output action, a clone (copy) of the packet is forwarded in its currentstate to the desired port where it starts egress processing. If the output action references the ALLreserved port, a clone of the packet start egress processing for each relevant port (see 4.5). If the outputaction references an non-existent port, the clone of the packet is dropped. If the list of actions containsa group action, a clone of the packet in its current state is processed by the relevant group buckets (see



5.10). The set of pipeline fields is cloned with the packet. Any modifications done to a clone of thepacket or its pipeline fields generated by the output or group action, for example changing a headerfield or the metadata field in a group bucket or an egress table, applies only to that clone and does notapply to the original packet or other clones.

After the execution of the list of actions in an Apply-Actions instruction, pipeline execution continueson the modified packet (see 5.1). The action set of the packet is unchanged by the execution of the listof actions.

5.8 Actions

A switch is not required to support all action types, just those marked Required Action below. Thecontroller can also query the switch about which of the Optional Action it supports.

Required Action: Output port no. The Output action forwards a packet to a specified OpenFlow port(see 4.1) where it starts egress processing. OpenFlow switches must support forwarding to physicalports, switch-defined logical ports and the required reserved ports (see 4.5).

Required Action: Group group id. Process the packet through the specified group (see 5.10). Theexact interpretation depends on group type.

Required Action: Drop. There is no explicit action to represent drops. Instead, packets whose actionsets have no output action and no group action must be dropped. This result could come from emptyinstruction sets or empty action buckets in the processing pipeline (see 5.6), or after executing a Clear-Actions instruction (see 5.5).

Optional Action: Set-Queue queue id. The set-queue action sets the queue id for a packet. When thepacket is forwarded to a port using the output action, the queue id determines which queue attachedto this port is used for scheduling and forwarding the packet. Forwarding behavior is dictated by theconfiguration of the queue and is used to provide basic Quality-of-Service (QoS) support (see section7.3.5.8).

Optional Action: Meter meter id. Direct packet to the specified meter (see 5.11). As the result ofthe metering, the packet may be dropped (depending on meter configuration and state). If the switchsupports meters, it must support this action as the first action in an list of actions, for backwardcompatibility with earlier versions of the specification. Optionally, a switch supporting meters may alsosupport the meter action in other positions in an list of actions, multiple meter actions in an list ofactions and the meter action in the action set (see section 7.3.5.14).

Optional Action: Push-Tag/Pop-Tag ethertype. Switches may support the ability to push/pop tagsas shown in Table 2. To aid integration with existing networks, we suggest that the ability to push/popVLAN tags be supported.

Newly pushed tags should always be inserted as the outermost tag in the outermost valid location forthat tag (see 7.2.6.6). When multiple push actions are added to the action set of the packet, they applyto the packet in the order defined by the action set rules, first MPLS, then PBB, than VLAN (see 5.6).When multiple push actions are included in a list of actions, they apply to the packet in the list order(see 5.7).

Note: Refer to section 5.8.1 for information on default field values.



Action Associated Data DescriptionPush VLAN header Ethertype Push a new VLAN header onto the packet.

The Ethertype is used as the Ethertype for the tag. OnlyEthertype 0x8100 and 0x88a8 should be used.

Pop VLAN header - Pop the outer-most VLAN header from the packet.Push MPLS header Ethertype Push

Technology

Openflow switch-v1.5.0.noipr