1. Cabo: Concurrent Architectures are Better than One Nick Feamster, Georgia Tech Lixin Gao, UMass Amherst Jennifer Rexford, Princeton

2. 2 Network Virtualization

3. 3 Flexible Network Topology

4. 4 VINI: Virtual Network Infrastructure XORP (routing protocols) UML eth1eth3eth2eth0 Click Packet Forward Engine Control Data UmlSwitch element Tunnel table Filters Experimentation with new architectures (bake off) –Experiments can share same physical infrastructure –Important characteristics for repeatable experiments Simultaneous experiments Long-running deployment studies Resource isolation

5. 5 Idea: Infrastructure is the Architecture Pluralist: No single winning architecture –Simultaneously running architectures Network Operations –Transitioning to new software, configurations, etc. –Different networks for different services (e.g., VoIP) –Security: sandboxing unwanted traffic –Topology-specific routing protocols ISPs rent slices of resources to each other –Or, perhaps even rent resources from third parties

6. 6 Today: ISPs Serve Two Roles Infrastructure providers: Maintain routers, links, data centers, other physical infrastructure Service providers: Offer services (e.g., layer 3 VPNs, performance SLAs, etc.) to end users Role 1: Infrastructure ProvidersRole 2: Service Providers No single party has control over an end-to-end path.

7. 7 Coupling Causes Problems Deployment stalemates: Secure routing, multicast, etc. –Focus on incremental deployability cripples us Shrinking profits and commoditization: ISPs cannot enhance end-to-end service –No single ISP has purview over an entire path As of 5:30 am EDT, October 5 th, [2005], Level(3) terminated peering with Cogent without cause…even though both Cogent and Level(3) remained in full compliance …We are extending a special offering to single homed Level 3 customers. Cogent will offer any Level 3 customer, who is single homed to the Level 3 network on the date of this notice, one year of full Internet transit free of charge at the same bandwidth currently being supplied by Level 3. … How do you think they're going to get to customers? Through a broadband pipe.. we have spent this capital and we have to have a return … there's going to have to be some mechanism for these people who use these pipes to pay for the portion they're using. –Edward Witacre Peering Tiffs: End-to-end connectivity is in the balance

8. 8 Proposal: Concurrent Architectures are Better than One (Cabo) The business entities that play these two roles may be the same in some cases Infrastructure providers: maintain physical infrastructure needed to build networks Service providers: lease slices of physical infrastructure from one or more providers

9. 9 Similar Trends in Other Industries Commercial aviation –Infrastructure providers: Airports –Infrastructure: Gates, hands and eyes, etc. –Service providers: Airlines Other examples: Automobile industry SFO ATL BOS ORD

10. 10 Communications Networks, Too! Packet Fabric: share routers at exchange points FON: resells users wireless Internet connectivity Infrastructure providers: Buy upstream connectivity, broker access through wireless Nomads: Users who connect to access points Service provider: FON as broker Two commercial examples Broker

11. 11 Application #1: End-to-End Services Secure routing protocols Multi-provider VPNs Paths with end-to-end performance guarantees TodayCabo Competing ISPs with different goals must coordinate Single service provider controls end-to-end path

12. 12 Application #2: Virtual Co-Location Problem: ISP/Enterprise wants presence in some physical location, but doesnt have equipment there. Today: Backhaul, or L3 VPN from single ISP Cabo: Lease a slice of anothers routers, links TokyoNYCATL

13. 13 Challenge #1: Embedding Given: virtual network and physical network –Topology, constraints, etc. Problem: find the appropriate mapping onto available physical resources (nodes and edges) Many possible formulations –Specific nodes mapping to certain physical nodes –Generic requirements: three diverse paths from SF to LA with 100 MBps throughput –Traffic awareness, dynamic remapping, etc. –Approximate solutions

14. 14 Challenge #2: Simultaneous Operation Problem: Service providers must share infrastructure Approach: Virtualize the infrastructure –Nodes PlanetLab Virtual Machines Virtual Routers –Links (previous lessons in QoS?) Capabilities are similar to those needed for VINI –Many of the same functions needed –Likely more federation in Cabo

15. 15 Challenge #3: Substrate Problem: Service providers must be able to request physical infrastructure (infrastructure providers must be able to instantiate it) –Discovering physical infrastructure Decision elements (cf. 4D proposal) –Creating virtual networks Requests to decision elements (initially out of band), which name virtual network components –Instantiating virtual networks Challenges include embedding and accounting

16. 16 Requirements Router virtualization –Scheduling of node CPU, link bandwidth, etc. Programmable software in each slice –Service providers will customize Support for substrate –Out-of-band communication –Accounting: what bandwidth has been reserved?

17. 17 Economic Challenges Service providers: great deal –Opportunity to add value by creating new services –Service differentiation Infrastructure providers –Can being an infrastructure provider be profitable? –Who will become infrastructure providers vs. service providers?

18. 18 Summary ISPs are infrastructure + service providers is problematic –Deployment stalemate –Commoditization Cabo: Concurrent Architectures are Better than One –Separate infrastructure from service providers Applications –Multi-provider VPNs, end-to-end services and protocols, … Challenges –Simultaneous operation –Bootstrapping More Information: http://www.cc.gatech.edu/~feamster/papers/cabo-tr.pdf