Bài giảng Các giao thức định tuyến: SDN (Software defined network)

Bài giảng Các giao thức định tuyến: SDN (Software defined network). Chương này cung cấp cho học viên những nội dung gồm: Các “mặt phẳng” trong mạng; kế hoạch dữ liệu; kế hoạch kiểm soát; kế hoạch quản lý; mạng SDN; ứng dụng SDN - ảo hóa mạng; chương trình điều khiển;... Mời các bạn cùng tham khảo chi tiết nội dung bài giảng!
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Bài giảng Các giao thức định tuyến: SDN (Software defined network)SDN-SoftwareDefinedNetwork Các“mặtphẳng”trongmạng•  Dataplane:processinganddeliveryofpacketswith localforwardingstate –  Forwardingstate+packetheaderàforwardingdecision –  Filtering,buffering,scheduling•  Controlplane:computingtheforwardingstatein routers –  Determineshowandwherepacketsareforwarded –  Routing,trafficengineering,failuredetection/recovery,...•  Managementplane:configuringandtuningthe network –  Trafficengineering,ACLconfig,deviceprovisioning,... Dataplan Data PlaneStreaming algorithms on packets –  Matching on some header bits –  Perform some actionsExample: IP Forwarding 1.2.3.4 1.2.3.7 1.2.3.156 5.6.7.8 5.6.7.9 host host ... host host host ... host LAN 1 LAN 2 router router router WAN WAN 1.2.3.0/24 5.6.7.0/24 11 forwarding table Controlplan•  Computepathsthepacketswillfollow –  Populateforwardingtables –  Traditionally,adistributedprotocol•  Example:Link-staterouting(OSPF,IS-IS) –  Floodtheentiretopologytoallnodes –  Eachnodecomputesshortestpaths –  Dijkstra’salgorithm Controlplan 1.  Figure out which routers and links are present. 2.  Run Dijkstra’s algorithm to find shortest paths. “If a packet is going to B, then send it to output 3”Data 2 1 “If , send to 3” 3 Managementplan Management PlaneTraffic Engineering: setting the weights –  Inversely proportional to link capacity? –  Proportional to propagation delay? –  Network-wide optimization based on traffic? 2 3 1 1 3 2 3 1 5 4 3 15 Timescales Timescales Data Control ManagementTime- Packet Event (10 Human (minscale (nsec) msec to sec) to hours)Location Linecard Router Humans or hardware software scripts 9DataplanvsControlplan Data and Control Planes control planedata plane Processor Line card Line card Line card Switching Line card Fabric Line card Line card 10 SDNNetwork•  Anetworkinwhichthecontrolplaneis physicallyseparatefromthedataplane. –  Controlplanofconventionalroutersaremoved uptocentralizedcontrolprograms•  Asingle(logicallycentralized)controlplane controlsseveralforwardingdevices SDNnetwork SoJwareDefinedNetwork(SDN) ControlProgramA ControlProgramB NetworkOS Packet Forwarding Packet Forwarding Packet Packet ForwardingForwarding Packet Forwarding 26 ApplicationofSDN:Network virtualisation•  Consideramulti-tenantdatacenter –  Wanttoalloweachtenanttospecifyvirtualtopology –  Thisdefinestheirindividualpoliciesandrequirements•  Datacenter’snetworkhypervisorcompilesthese virtualtopologiesintosetofswitch configurations –  Takes1000sofindividualtenantvirtualtopologies –  Computesconfigurationstoimplementall simultaneously•  Thisiswhatpeoplearepayingmoneyfor.... –  EnabledbySDN︎sabilitytovirtualizethenetwork Controlprogram•  Controlprogramoperatesonviewofnetwork –Input:globalnetworkview(graph/database) –Output:configurationofeachnetwork device•  Controlprogramisnotadistributedsystem –  Abstractionhidesdetailsofdistributedstate NetworkOS(onController)•  NetworkOS:createsaconsistent,up-to-date networkview –  Runsonservers(controllers)inthenetwork –  ONOS,NOX,ONIX,Floodlight,Trema, OpenDaylight,HyperFlow,Kandoo,Beehive, Beacon,Maestro,...+more•  Usesforwardingabstractionto: –  Getstateinformationfromforwardingelements –  Givecontroldirectivestoforwardingelements OpenFlowbasics OpenFlow BasicsControl Program A Control Program B NetworkOS OpenFlowProtocolEthernet Switch Control Path OpenFlow Data Path (Hardware) 35 OpenFlowbasics•  Meansofcommunicationbetweencontrollerand switch•  OpenFlowenablesnetworkcontrollerstodetermine thepathofnetworkpacketsacrossanetworkof switches•  O ...