Jennifer Rexford Princeton University MW 11:00am-12:20pm

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SDN Software Stack COS 597E: Software Defined Networking. Jennifer Rexford Princeton University MW 11:00am-12:20pm. Background: Enterprise Networks and VLANs. Internet. Simple Enterprise Design. Single layer-two subnet Hubs and switches Gateway to the Internet Single IP address block. - PowerPoint PPT Presentation

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Understanding, Accommodating, and Leveraging Radical Changes in Mobility of Users, Devices, and Software

Jennifer RexfordPrinceton UniversityMW 11:00am-12:20pmSDN Software StackCOS 597E: Software Defined NetworkingBackground: Enterprise Networks and VLANs2Simple Enterprise DesignSingle layer-two subnetHubs and switchesGateway to the InternetSingle IP address blockLocal servicesDHCPDNS3SSSGS

DHCP serverDNS server1.2.3.11.2.3.761.2.3.51.2.3.150

Internet1.2.3.0/240.0.0.0/0Limitations of Simple DesignScalabilityLarge switch tablesFlooding overheadBroadcast (ARP, DHCP)PerformanceSpanning treeSecurityNo access controlNo isolation4SSSGS

DHCP serverDNS server1.2.3.11.2.3.761.2.3.51.2.3.150

Internet1.2.3.0/240.0.0.0/0Hybrid of Switches and Routers5RRRREthernet Bridging - Flat addressing - Self-learning - Flooding - Forwarding along a treeIP Routing - Hierarchical addressing - Subnet configuration - Host configuration - Forwarding along shortest pathsR1.2.3.192/261.2.3.128/261.2.3.0/261.2.3.64/26

InternetVirtual Local Area NetworksGroup related hostsSame company Same role (e.g., faculty vs. students)All WiFi usersTreat them as a single LANSingle IP address blockSingle broadcast domainNo access controlIndependent of their location6Rewire the network in software!Example: Two VLANs7Red VLAN and Orange VLANSwitches forward traffic as neededRORORRROOORORRROOOMaking VLANs WorkChanging the Ethernet headerAdding a field for a VLAN tagImplemented on the bridges/switches but can interoperate with old Ethernet cardsBridges/switches trunk linksSay which VLANs are accessible via which interfacesApproaches to mapping access links to VLANsEach interface has a VLAN colorEach MAC address has a VLAN color8VLANs in SDNHybrid deploymentVLAN for SDN adoptersRemaining traffic using legacy protocolsSwitch-controller communicationSeparate VLAN Using legacy protocolsTagging of packetsVLAN header as a virtual tag on packets9Server Virtualizationand Virtual Switches10Virtual Machines (VMs)11

Virtual Machine (VM)Virtual machineSoftware implementation of a computerWith interface identical to bare hardwareDevices, interrupts, memory, page tables, etc.Hypervisor (virtual machine monitor)Creates and runs virtual machinesManages execution of the guest OSesSubdivides the hardware resourcesExecutes privileged instructions

12Motivations for VMsDiverse operating systemsRunning software for obsolete platformsResearch, experimentation, and testingSharing a single hostServer consolidation (lower cost, energy)Isolation of applications or customers/tenantsFast provisioning of new serversSnapshotting system stateBackup and redeploymentMigrating a VM to a different host machineVM introspectionTrack configuration settingsIdentify configuration mistakes or compromises

13Virtual Switches14

SDN Software Stack15SDN Software Stack16Network OSApplicationSwitchSwitchSwitchAPISDN Software Stack17NOXApplicationOVSOVSOVSOpenFlowDiscussionWhat is a good division of labor?Good design for the protocol?Good abstractions for the NOS?How apt is the operating system analogy?What parts of the system need standards?What are interesting SDN applications?

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