VROOM: Virtual ROuters On the Move Yi Wang (Princeton) With: Kobus van der Merwe (AT&T Labs - Research) Jennifer Rexford (Princeton)

2  Key idea Routers should be free to roam around  Useful for many network management tasks Simplify network maintenance Simplify service deployment Save power …  Feasible in practice Virtual ROuters On the Move (VROOM)

3 VROOM: The Basic Idea  Virtual routers (VRs) form logical topology physical router virtual router physical link logical link

4 VROOM: The Basic Idea  VR migration does not affect the logical topology physical router virtual router physical link logical link

5 Tight Coupling of Logical and Physical  Today, the physical and logical configurations of a router is tightly coupled Hardware upgrade requires logical re-configuration Customer re-homing requires re-configuration  The less re-configurations, the better Less protocol reconvergence Less traffic disruption Less configuration errors and overhead

6 VROOM Separates the Logical and Physical  All logical configurations/states remain the same before/after the migration IP addresses remain the same Routing protocol configurations remain the same Routing-protocol adjacencies stay up No protocol (BGP/IGP) reconvergence  Network topology stays intact Adjacent routers won’t know the router has moved  Virtually no disruption to traffic Our most recent results show that the traffic downtime can be eliminated

7 Application 1: Planned Maintenance  Today’s best practice: “cost-out/cost-in” Router reconfiguration & protocol reconvergence  VROOM NO reconfiguration of VRs, NO reconvergence PR-A VR-1 PR-B

8 Application 1: Planned Maintenance  Today’s best practice: “cost-out/cost-in” Router reconfiguration & protocol reconvergence  VROOM NO reconfiguration of VRs, NO reconvergence PR-A VR-1 PR-B

9 Application 1: Planned Maintenance  Today’s best practice: “cost-out/cost-in” Router reconfiguration & protocol reconvergence  VROOM NO reconfiguration of VRs, NO reconvergence PR-A VR-1 PR-B

10 Application 1: Planned Maintenance  Today’s best practice: “cost-out/cost-in” Router reconfiguration & protocol reconvergence  VROOM NO reconfiguration of VRs, NO reconvergence PR-A VR-1 PR-B

11 Application 1: Planned Maintenance  Today’s best practice: “cost-out/cost-in” Router reconfiguration & protocol reconvergence  VROOM NO reconfiguration of VRs, NO reconvergence PR-A VR-1 PR-B

12 Application 2: Service Deployment Production network Test network CE  Deploy a new service in a controlled “test network” first

13 Application 2: Service Deployment Production network Test network  Roll the service out to the production network after it matures  VROOM guarantees seamless service to existing customers during the roll-out

14 Application 3: Power Saving  Big power consumption of routers Millions of Routers in the U.S. Electricity bill: $ hundreds of millions/year (Source: National Technical Information Service, Department of Commerce, Figures for 2005 & 2010 are projections.)

15 Application 3: Power Saving  Observation: the diurnal traffic pattern  Idea: contract and expand the physical network according to the traffic demand

16 Application 3: Power Saving Dynamic change in a day - 3PM

17 Application 3: Power Saving Dynamic change in a day - 9PM

18 Application 3: Power Saving Dynamic change in a day - 4AM

19 Enabling Technologies 1.Virtual routers Vendors: Cisco VRF, Juniper logical routers, … Research community: GENI, Cabo, … Today’s virtual routers have to stay put 2.Live virtual machine migration Available from VMWare, Xen, … Typically limited to LANs Don’t have dedicated forwarding engine (e.g., FIBs, line cards, …)

20 Enabling Technologies 3.Programmable transport layers Long-haul links are reconfigurable  Layer 3 point-to-point links are multi-hop at layer 1/2 Benefit for VROOM: links are easily migratable Chicago New York Washington D.C. : Multi-service optical switch (e.g., Ciena CoreDirector)

21 Enabling Technologies 3.Programmable transport layers Long-haul links are reconfigurable  Layer 3 point-to-point links are multi-hop at layer 1/2 Benefit for VROOM: links are easily migratable Chicago New York Washington D.C. : Multi-service optical switch (e.g., Ciena CoreDirector)

22 Enabling Technologies 4.Packet-aware access networks Access links are becoming inherently virtualized  Customers connects to provider edge (PE) via pseudo- wires (virtual circuits) Benefit for VROOM: multiple customers can share the same physical interface on PE routers Dedicated physical port Shared physical port

23  These enabling technologies offer great flexibilities from physical layer to IP layer  VROOM harnesses these flexibilities in a structured way to power network management

24 VROOM Architecture  Virtual router migration Dynamic bindings between logical interfaces and physical interfaces

25 VROOM Architecture  Virtual link migration Leverage programmable transport networks

26 VROOM Architecture  Minimize downtime In commercial routers, data plane runs in dedicated hardware (line cards) Idea: keep the data plane forwarding traffic while migrating the control plane

27 Deciding Where To Migrate  Physical constraints Latency  E.g, NYC to Washington D.C.: 2 msec Link capacity  Enough remaining capacity for extra traffic Platform compatibility  Routers from different vendors Router capability  E.g., number of ACLs supported  Good news: these constraints limit the search space of migration destinations

28 Conclusions & Ongoing Work  Conclusions VROOM separates the tight coupling between physical and logical router configurations Simplify network management, enable new applications  Ongoing work Formulate migration scheduling as a constrained optimization problem, create automated solver Prototype with NetFPGA card as data plane Explore other VROOM applications

29 Thanks! Questions & Comments Please! Contact: Yi Wang

30 Backup Slides

31 VROOM Architecture  Edge migration Leverage packet-aware transport networks  Virtualized interfaces (label-based)  Virtualized access links (pseudo-wires)  No need for a per customer physical interface on PE routers

32 Packet-aware Access Network

33 Packet-aware Access Network PE CE P/G-MSS: Packet-aware/Gateway Multi-Service Switch MSE: Multi-Service Edge Pseudo-wires (virtual circuits) from CE to PE

34 Events During Migration  Network failure during migration The old VR image is not deleted until the migration is confirmed successful  Routing messages arrive during the migration of the control plane BGP: TCP retransmission OSPF: reliable flooding

35 Prototype Evaluation  Configure a Xen virtual machine to work as a software router  Leverage the live migration functionality provided by Xen  Use GRE tunnels to emulate virtual links No assumption on the underlying physical/link layer technology

36 Prototype Evaluation  Before migration

37 Prototype Evaluation  During migration (VR migrated, links not yet)

38 Prototype Evaluation  After migration (VR & links migrated)

39 Prototype Evaluation  Ping packets between NR1 and NR2 (1 msec interval)  Observations Increased latency during migration Short period of downtime at the end of migration 563 msec