1、The “Platform as a Service” Model for Networking,Eric Keller, Jennifer Rexford Princeton UniversityINM/WREN 2010,Hosted Infrastructures,Shift towards hosted and shared infrastructures Cloud computingBenefits: Dynamically scale up/down Cost benefits,2,Hosted Network Infrastructure,Poised to happen fo
2、r networking Similar benefits Additional driver: in-network inaccessibility,?,3,Old News,Im not the first to believe this Large body of research in Network Virtualization Run multiple virtual networks concurrently on a shared infrastructure,4,Thats the Wrong Approach,Instead abstraction should be a
3、platform Customers can focus on their application/service “Single Router Platform”,5,Whats the problem with network virtualization?,6,Undesirable Business Model (for infrastructure provider),Infrastructure Providers,Applications,End Users,Service Providers,Owns and maintains physical routers/links,B
4、uilds application which uses in-network functionality (e.g., Virtual Worlds provider using a multi-cast service),Leases slices of virtualized routers to create network Runs custom software/protocols/configurations (e.g., a multi-cast or reliable connectivity),7,Infrastructure Providers,Applications,
5、End Users,Service Providers,Owns and maintains physical routers/links,Builds application which uses in-network functionality (e.g., Virtual Worlds provider using a multi-cast service),Leases slices of virtualized routers to create network Runs custom software/protocols/configurations (e.g., a multi-
6、cast or reliable connectivity),Commodity Service (unappealing to traditional ISPs),Undesirable Business Model (for infrastructure provider),8,Difficult to Manage (for application providers),Same as managing physical network Traffic engineering Configuring a distributed collection of routers Deal wit
7、h failure Managing resources to meet demandYes, but wont service providers deal with that?,9,Limited Market Opportunity (for service providers),Applications just want some control Either service provider provides it or develop themselves Services must be general to have a large market Are there real
8、ly that many generic services? Dont count on infrastructure providers Thats todays model,10,If not network virtualization, then what?,11,Cloud Computing Landscape,Infrastructure as a Service (IaaS) e.g., Amazon EC2, Rackspace Cloud Abstraction is managing set of virtual machines Freedom: run any sof
9、tware you want Effort: manage redundancy, all software Platform as a Service (PaaS) e.g., Google App Engine, Heroku Write application using libraries and without worrying about actual servers Freedom: tied to specific platform capabilities Effort: apps scale automatically, build on the platform (And
10、 everything in between),12,Key Differences (why IaaS makes sense for computing),Compute: Legacy applications Workflow used to writing applications on servers Network: Limited developer community Not the end application,Platform enabling in-network functionality, without having to manage a network,Go
11、al,13,The Router Platform (PaaS),Present customers (application developers) with platform Decoupled from physical infrastructure Customers can focus on their application/service Infrastructure owner has freedom in managing the infrastructure,14,The Single Router Abstraction,Router abstraction covers
12、 functionality, doesnt bother with physical infrastructure Router more than just routing Note: this is preliminary thinking,Data Plane,Routing Software,General purpose functions,Customer Program,API,15,Interactive Program,Customer provides executable script (rather than static configuration file) In
13、itialization routine Dynamic modification to configuration Driven by events (control message, event notification),Data Plane,Routing Software,General purpose functions,Customer Program,API,16,Routing,Specify sessions with neighboring routers Customers routers or infrastructure providers neighbors Kn
14、ow what links are available Interface to query, metrics, callback when change,Data Plane,Routing Software,General purpose functions,Customer Program,API,17,Data Plane,Direct configuration of data plane functions Setting up multi-cast groups, access control lists, etc.,Data Plane,Routing Software,Gen
15、eral purpose functions,Customer Program,API,18,General-Purpose Processing,As name suggest, can be anything Can be written by customer as well,Data Plane,Routing Software,General purpose functions,Customer Program,API,19,Customer Controlled Routing,ISP chooses one route, no choice to customers Custom
16、er: Configure Router in ISP,Dest.,C1,C2,ISP,X,Y,Low cost route,Low latency route,20,Cloud Computing,IaaS offerings give you servers and connectivity Customer: configure middlebox (firewall, load balancer), VPN, route selection,21,Gaming/Live Video Streaming,Limited ability to setup multi-cast, perfo
17、rm update aggregation Customer: configure router to manage multi-cast group, add custom software,update,22,Gaming/Live Video Streaming,Limited ability to setup multi-cast, perform update aggregation Customer: configure router to manage multi-cast group, add custom software,update,23,Challenge: The P
18、hysical Reality,24,Challenge: The Physical Reality,Physical Infrastructure is Distributed,25,Challenge: The Physical Reality,Physical Infrastructure is Distributed Physical Infrastructure is Shared,Customer 1,Customer 2,Customer 3,26,Distributed Router Workload,Network virtualization specify exact t
19、opology Single router platform specify work to be doneLeeway to distribute this workload Some tied to physical router (e.g., BGP session) Some can be replicated (for latency or to handle work) Configure “inter-processor communication”,27,Dynamically Adjust Distribution,Estimates are used to choose h
20、ow to distribute Monitor the routers CPU, update freq., traffic Re-distribute workload as necessary e.g., migrate BGP session e.g., add replicated instances Comes at cost,28,Shared Infrastructure,Virtualization is part of solution Routing sessions can be shared Tag message, process it, send out base
21、d on tag,C1,C2,Inf Prov,29,Conclusion,Shift towards hosted and shared infrastructure Can help management of private infrastructures Worth exploring an alternate to the IaaS model Some challenges in the single router platform,30,Questions?,Contact info: ekellerprinceton.edu http:/www.princeton.edu/ekeller,31,
