WIXLIB

Depart. Electronic EngineeringMobile Intelligent Network LabActions and Packet Forwarding (2/4)- CONTROLLER indicates that theswitch should forward this packetto the controller- IN PORT instructs the switch toforward the packet back out of theport on which it arrived.- TABLE only applies to packetsthat the controller sends to theswitch. The packets are then processed bynormal OpenFlow packet processingpipeline.Lab21042

Depart. Electronic EngineeringMobile Intelligent Network LabActions and Packet Forwarding (3/4) In V.1.0, there are two optionalvirtual ports: NORMAL andFLOOD.- A packet forwarded to NORMALport is sent to legacy forwardinglogic in the case of a hybrid switch.- FLOOD instructs the switch to senda copy of the packet along minimumspanning tree, except the input port.Lab21043

Depart. Electronic EngineeringMobile Intelligent Network LabActions and Packet Forwarding (4/4) For a table miss, the virtual port CONTROLLER is used. There are two optional actions in V.1.0: enqueue and modifyfield.- Enqueue specifies a queue to a particular port.- Modify-field informs the switch how to modify certain header fields.The action box has three fundamental options:(A) Forward the packet out, possibly modifyingcertain header fields first(B) Drop the packet(C) Pass the packet to the controller through aOpenFlow PACKET IN (Pkt In) messageLab21044

Depart. Electronic EngineeringMobile Intelligent Network LabMessaging Between Controller andSwitch If the switch knows the IP address of the controller, the switchwill initiate this connection. Each message between controller and switch starts with theOpenFlow header.Lab21045

Depart. Electronic EngineeringMobile Intelligent Network LabOpenFlow Message Types andProtocol SessionLab21046

Depart. Electronic EngineeringMobile Intelligent Network LabInitialization Phase The HELLO messagesare exchangedto determine the highest OpenFlowversion supported by the peers,where the lower of the two is used. The controller uses the FEATURESmessage pair to interrogate theswitch about the supported features. The controller modifies existing flowentries in the switch via theFLOW MOD message.Lab21047

Depart. Electronic EngineeringMobile Intelligent Network LabOperation Phase The PACKET IN message is the waythe switch passes data packets backto the controller for exceptionhandling. The controller uses PACKET OUT tosend data packets to the switch forforwarding out through the dataplane.Lab21048

Depart. Electronic EngineeringMobile Intelligent Network LabMonitoring Phase ECHO messages are used byeither side to ascertain that theconnection is still alive and tomeasure the current latency orbandwidth of the connection. PORT STATUS is used tocommunicate changes in portstatus. Statistics are obtained from theswitch via the STATS message pair.Lab21049

Depart. Electronic EngineeringMobile Intelligent Network LabExample: Controller Programming Flow Tableinput port(1/3) Adding aflow entryAdding a flow for packets entering theswitch on any port, with source IPaddresses 192.168.1.1 and destination IPaddress 209.1.2.1, source TCP port 20,and destination port 20. All other matchfields have been wildcarded. The outportport is specified as P.destinationEthernetaddressoutput portAll Ethernet frames entering theswitch on input port K with adestination Ethernet address of0x000CF15698AD should be outputon output port N.source IPdestination IPLab210output port50

Depart. Electronic EngineeringMobile Intelligent Network LabExample: Controller Programming Flow Table(2/3) Modifying aflow entryAt time tb, the controller sends aFLOW MOD (MODIFY) commandfor flow entry zero. The controllerseeks to modify the correspondingflow entry such that there is a onehour (3600-second) idle time on thatflowLab21051

Depart. Electronic EngineeringMobile Intelligent Network LabExample: Controller Programming Flow Table(3/3) A packet arriving at theswitch through port 2 withsource IPv4 address of192.168.1.1 and destinationIPv4 address of 209.1.2.1. The packet-matching functionscans the flow table startingat flow entry 0 and finds amatch in flow entry F. Flow entry F stipulates that amatching packet should beforwarded out port P.Lab21052

Depart. Electronic EngineeringMobile Intelligent Network LabExample: Switch Forwarding Packet toControllerLab21053

Depart. Electronic EngineeringMobile Intelligent Network LabOpenFlow 1.1 AdditionsLab21054

Depart. Electronic EngineeringMobile Intelligent Network LabOpenFlow V.1.1 OpenFlow 1.1 had little impact other thanas a stepping stone to OpenFlow 1.2. SDN community waited for V.1.2 (the firstversion by ONF) before creatingimplementations. Five major new features-Multiple flow tablesGroupsMPLS and VLAN tag supportVirtual portsController connection failureLab21055

Depart. Electronic EngineeringMobile Intelligent Network LabMultiple Flow Tables In V.1.1, it is possible to defer further packet processing tosubsequent matching in other flow tables. Instruction is introduced to be associated with a flow entry. Flow tables can be chained by GOTO instructions.Lab21056

Depart. Electronic EngineeringMobile Intelligent Network LabMultiple Flow Tables For an incoming packet, an action set is initialized and then modifiedby instructions through the processing pipeline. When the pipeline ends, the actions in the action set are executed inthe following order:1. Copy TTL inward4. Copy TTL outward7. QoS: Apply QoS actions (e.g.set queue)2. Pop5. Decrement TTL8. Group: Apply actions torelevant action buckets if agroup action is specified3. Push6. Set: Apply set field actions9. Output to specified portLab210 If there is neither a group nor output action, the packet is dropped57

Depart. Electronic EngineeringMobile Intelligent Network LabMultiple Flow Tables Note that actions specified by an Apply-Actions instruction areimmediately executed. When a matched flow entry does not specify a GOTO flow table,the processing pipeline completes, and actions in the currentaction set are then executed. In normal cases, the final action is to forward a packet to anoutput port, to the controller, or to a group table. The flexibility of multiple flow tables comes at a price forLab210adapting existing hardware switches58

Depart. Electronic EngineeringMobile Intelligent Network LabExample: Multiple Flow Tables The packet first matches entry 1 inTable 0.- An action “output to port P” is addedto the action set.- The pipeline then jumps to Table Kaccording to the GOTO instruction. The packet matches entry F inTable K.- Since there is no GOTO instructionhere, actions in the action set areexecuted.Lab21059

Depart. Electronic EngineeringMobile Intelligent Network LabGroups Group table consists of groupentries.- Each entry consists of one or moreaction buckets. Refinements on flooding, such asmulticast, can be achieved inV.1.1 by defining groups asspecific sets of ports. One group’s buckets may forwardto other groups, providing thecapability to chain groups togetherLab21060

Depart. Electronic EngineeringMobile Intelligent Network LabGroupsLab21061

Depart. Electronic EngineeringMobile Intelligent Network LabMPLS and VLAN Tag Support Multiprotocol label switching (MPLS) and virtual local areanetworks (VLAN) are supported by adding PUSH and POPactions.- When a PUSH action is executed, a new header (or tag) is inserted infront of the current outermost header.- On the other hand, POP is used to remove the current outermostheader. The matching logic is replaced by V.1.2, and will be discussedlater.Lab21062

Depart. Electronic EngineeringMobile Intelligent Network LabVirtual Ports A V.1.1 switch classifies ports into standard ports and reservedvirtual ports. Standard ports consist of- Physical ports- Switch-defined virtual ports Reserved virtual ports consist of-ALL,CONTROLLER,TABLE,IN PORT,LOCAL (optional),NORMAL (optional)FLOOD (optional)Lab21063

Depart. Electronic EngineeringMobile Intelligent Network LabController Connection Failure Two modes are introduced for loss of connection betweenswitch and controller:- In fail secure mode, the switch continues to operate as a normal V.1.1 switch except that all messagesdestined for the controller are dropped.- In fail standalone mode, the switch additionally ceases its OpenFlow pipeline processing and continues tooperate in its native, underlying switch or router mode.Lab21064

Depart. Electronic EngineeringMobile Intelligent Network LabOpenFlow 1.2 AdditionsLab21065

Depart. Electronic EngineeringMobile Intelligent Network LabOpenFlow V.1.2 Eight major new features1.2.3.4.5.6.7.8.Extensible match supportExtensible set field packet-rewriting supportExtensible context expression in “packet-in”Multiple controller enhancementsExtensible error messages via experimenter error typeIPv6 supportSimplified behavior of flow-mod requestRemoved packet parsing specificationLab21066

Depart. Electronic EngineeringMobile Intelligent Network LabExtensible Match Support A generic and extensible packet-matching capability has beenadded in V.1.2 via the Openflow Extensible Match (OXM)descriptors.- OXM defines a set of type-length-value (TLV) pairs that can describe ordefine virtually any of the header fields.Lab21067

Depart. Electronic EngineeringMobile Intelligent Network LabExtensible Match SupportLab210OXM TLV Layout68

Depart. Electronic EngineeringMobile Intelligent Network LabExtensible Match Support The ability to match on any combination of header fields isprovided within the OPENFLOW BASIC match class. The EXPERIMENTER match class opens up the opportunity formatching on fields in the packet payload- providing a near-limitless horizon for new definitions of flows.Lab21069

Depart. Electronic EngineeringMobile Intelligent Network LabExtensible set field Packet RewritingSupport It is allowed to set the value of any packet header field that maybe used for matching. For EXPERIMENTER match class,- it is possible to modify any packet fields (including the payload) that isnot part of the standard OXM header fields.Lab21070

Depart. Electronic EngineeringMobile Intelligent Network LabExtensible Context Expression inPACKET IN The OXM encoding is also used to extend the PACKET INmessage sent from the switch to the controller.Lab21071

Depart. Electronic EngineeringMobile Intelligent Network LabMultiple Controllers In V.1.2, the switch may be configured to maintain simultaneousconnections to multiple controllers. If a message pertains to multiple controllers, it is duplicated anda copy sent to each controller. Three different roles of controllers: slave, master and equal- In slave mode, the controller may only request data from the switch.- Both master and equal modes allow the controller the full ability toprogram the switch.- Only one controller in master mode is allowed, while other controllersare in slave mode.Lab21072

Depart. Electronic EngineeringMobile Intelligent Network LabOpenFlow 1.3 AdditionsLab21073

Depart. Electronic EngineeringMobile Intelligent Network LabOpenFlow V.1.3 OpenFlow V.1.3 was released on April 13, 2012.- This release was a major milestone, especially for ASIC designers.- It is likely that the real-life chips that support V.1.3 will have to limit thenumber of flow tables to a manageable number. Thirteen major new features1. Refactor capabilitiesnetogiation6. Auxiliary connections11. Cookies inPACKET IN2. More flexible table-misssupport7. MPLS BoS matching12. Duration for stats3. IPv6 extension headerhandling support8. Provider backbonebridging tagging13. On-demand flowcounters4. Per-flow meters9. Rework tag order5. Per-connection event filtering10. Tunnel-ID metadataLab21074

Depart. Electronic EngineeringMobile Intelligent Network LabMore Flexible Table-miss Support A table miss was configurable as one of three options:- dropping,- forwarding to the controller,- and continuing matching in the next table. V.1.3 expands on this limited handling capability via theintroduction of the table-miss flow entry.- The table-miss flow entry is of the lowest priority (zero) and all matchfields are wildcards.- The advantage of this approach is that full semantics of flow entry(including instructions and actions) are applicable for a table miss.- For example, a table-missed packet may be passed to another flowtable by a GOTO instruction for further processing.Lab21075

Depart. Electronic EngineeringMobile Intelligent Network LabPer-Flow Meters Meters are defined on a per-flowbasis and reside in a meter table. V.1.3 instructions may direct packetsto a meter identified by a meter ID. V.1.3 meters are only rate-limitingmeters.multiple meter bands There may be multiple meter bandsattached to a given meter.meter tableLab21076

Depart. Electronic EngineeringMobile Intelligent Network LabPer-Flow Meters When a packet is processed by a meter, at most one band is used. This band is selected based on the highest bandwidth rate band that islower than the current measured bandwidth for that flow. If the current measured rate is lower than all bands, no band is selected,and no action is taken. If a band is selected, the action prescribed by the band type field is taken.Lab21077

Depart. Electronic EngineeringMobile Intelligent Network LabExample: Enforcing QoS via MeterBands The packet from Port 2 matches a flowentry with an instruction which directsthe packet to Meter 3.- If the bandwidth limits are exceeded, thepacket is dropped.- Otherwise, the packet undergo furtherprocessing in the pipeline.Lab21078

Depart. Electronic EngineeringMobile Intelligent Network LabPer Connection Event Filtering In the previous versions, all controllers must receive the samekind and quantity of asynchronous notifications from the switch. V.1.3 introduces a SET ASYNC message that allows thecontroller to specify the sorts of async messages it is willing toreceive from a switch.Lab21079

Depart. Electronic EngineeringMobile Intelligent Network LabAuxiliary Connections As deployment of OpenFlow grows, performanceconsiderations have become increasingly important. V.1.3 allows multiple connections per controller-switch channel. The major advantage is to achieve greater overall throughput,both in control plane and data plane.Lab21080

Depart. Electronic EngineeringMobile Intelligent Network LabCookies in PACKET IN In the case of PACKET IN messages, it issomewhat wasteful to require the switch tomatch over and over for the same flow. V.1.3 allows the switch to pass a cookieV.1.3 flow entrywith the PACKET IN message.- The switch maintains the cookie in a new fieldin the flow entry.- The cookie allows the switch to cache the flowentry pointed to by this cookie, and prevent thefull packet-matching process.Lab21081

Depart. Electronic EngineeringMobile Intelligent Network LabLab21082

Standardization of OpenFlow The nonprofit Internet organization openflow.org was created in 2008. - As a mooring to promote and support OpenFlow. - The physical organization was really just a group of people that met informally at Stanford University. - The first release, OpenFlow1.0.0, appeared on Dec. 31, 2009.