Cross-Layer Optimization (CLO) Problem Statement

1. Cross-Layer Optimization (CLO) Problem Statement Young Lee, Susan Hares, Greg Bernstein

2. Application Layer (Host Layer) Distributed Resources: servers, content, data sets, computing power, cache/mirror Uses Network Resources Different QoS requirements for each application Cross-Layers Application Layer Transport Layer Transport to Network Layer • Bandwidth, Connections, Links, • Connection Processing (Creation, Deletion, Management) • Admission Control, Resource Reservation • Applications uses resources in IP, MPLS, and/or Optical Transport Networks, Layer 2 Network Layer

3. Applications need • Assured performance levels associated with the application. • Optimized resource utilization via cross-layer interaction between application and network layers, • A cross-layer management paradigm that is dynamic, interactive, elastic, adaptive, and flexible across application-network layers. • Elastic – stretches the network during growth • Adaptive – changes with network

4. Current and Emerging Application Resources • Live Data Sources • Video or audio from live sporting or entertainment events, data feeds from radio telescopes, remote medical surgery • Processing Resources • Raw computational capability for cloud computing, transactional capabilities for e-commerce, processing for streaming media, transcoding capabilities for video and audio, etc... • Storage Resources • Disk farms, tape libraries, etc... • Content/Data Sets • Video, audio, commercial, scientific, etc...

5. Application Service Profiles Characteristics & QoS Requirement of application service from a network perspective: • Location profile: locations of both the clients and the sources • QoS profile: (i) Delay Tolerance Bound; (ii) Jitter Tolerance Bound; (iii) PacketDelivery Ratio Tolerance; (iv) Network Availability, etc. • Connectivity profile: (i) P-P; (ii) P-MP; (iii) MP-MP; (iv) Any Cast • Directionality profile: (i) uni-directional; (ii) bi-directional • Bandwidth profile: Maximum, average, and minimum bandwidth requirements for the connectivity, maximum burst rate, maximum burst duration, etc. • Duration of service profile: service time of the application • Network media profile: (i) optical only; (ii) no microwave, etc. • Restoration profile: (i) Reroute required; (ii) do not re-route, etc. • Security profile: (i) dedicated end-to-end VPN-like resource allocation; (ii) dedicated physical resource allocation Communicate these application profiles to network via a common mechanism between application and network layer

6. File/Content Distribution Systems Download of images/audio/video/software via the network; Common optimization problems in this system includes: • Cache and Mirror placement problem • Coordination of the application and network (transport and IP) topological information is key to optimization • Efficient transfer of content to servers • Coordinated point-to-multipoint concurrent path optimized with network loading condition in both application and network is key to optimization • Client to server assignment problem • Current server load and network latency between client and server are key QoS

7. CDN Network Surrogate Surrogate Surrogate CE CE CE PE PE PE DNS server (ANC) TNC Transport Network Service request PE PE PE CE CE CE CE User User User User CE CE User User Content Distribution Network (CDN) • DNS server performs the ANC function. • It receives users’ requests • Based on surrogate’s availability, transport network resource and user’s position, it chooses the best surrogate to serve the user. • It sets up a PE-to-PE connection between the surrogate and the user through communication with the TNC in the transport network. • The users who share the same surrogate and the access PE can share the PE-to-PE connection. • B/W modification capability is also needed

8. Streaming Content Distribution Systems The streaming case increases the need for coordinated multi-layer monitoring and configuration primarily due to more stringent QoS constraints on bandwidth and jitter. • Optimization problems for a live streaming service include: • Server selection and placement problems (application based multi-cast) • Leaf attachment problem and tree construction (network-based multi-cast) • Additional optimization decisions required with on-demand streaming • Client stream sharing • Batch or multicast server selection problem

9. Video On Demand VoD Service Controller (ANC) 3. Download request 1. service request 2. VNT 3. Reserve End User Super Head End (SHE) Location 1 Content Distribution CE Local Area Head End 1 CE TNC PE Content Source PE Transport Network PE PE Super Head End (SHE) Location 2 CE End User CE PE Local Area Head End 2 Application Cloud End User ANC – Application Network Controller TNC- Transport Network Controller CE Local Area Head End 3 • VoD Service Controller (VSC) performs the ANC Function • Local Area HE sends a query the VSC for video download • VSC makes a decision which SHE should send the video to the Local Area HE based on: • Transport Network Topology (that TNC provides) and Server (SHE) status and • Movie Availability • QoS: Delay and Jitter sensitive • Connection: One-way

10. Conferencing and Gaming These applications increase the complexity of the overall application connectivity and the need for cross-layer coordination of monitoring, configuration. • Bi-directional connections and asymmetric bandwidth between the server and the user location • Multipoint-to-multipoint connectivity with hard QoS constraint on latency and bandwidth • Data path formation and reformation for MP-MP can be very inefficient without considering the underlying network resources • Network path computation and path reservation may be required to ensure the end-users service objective. • Gaming adds additional scalability on QoS requirement and the connectivity.

11. Video Conferencing Architecture Service request Meeting Room Destination 1 Video Conferencing Controller (ANC) CE PE 10 Mbps TNC Meeting Room Source Meeting Room Destination 2 30 Mbps CE PE PE CE PE CE PE Meeting Room Destination 3 CE Meeting Room Destination 4 ANC – Application Network Controller TNC- Transport Network Controller • Video Conferencing Controller (VCC) performs the ANC function. • It receives client requests • It sets up the P-MP connections via the TNC in the transport network • QoS: Delay and Jitter sensitive • Connection: Asymmetric P-MP connections (uplink: 10 Mbps; downlink: (N-1)*10 Mbps • where N is the number of participants) • Desk Top conferencing is envisioned to connect 100’s of clients which will require higher B/W.

12. Video Gaming Service Architecture Game Server Game Server Game Server CE CE CE PE PE PE Video Game Controller (ANC) Transport Network TNC PE PE Service request PE CE CE CE CE Gamer Gamer Gamer Gamer CE CE Gamer Gamer ANC – Application Network Controller TNC- Transport Network Controller • Video Game Controller (VGC) performs the ANC function. • It receives client requests • It sets up the P-P connections via the TNC in the transport network • Server location and B/W availability from Server to Client are key info for decision • B/W modification capability is critical • QoS: Delay and Jitter sensitive • Connection: Asymmetric P-P/MP-MP connections (uplink: 100 Mbps; downlink: 10 Mbps) • Up to 100,000 clients connections (E.g., Worldwide war games)

13. Grid Computing/Remote Medical Grid computing supports extremely large transfers of files and streaming data. The volume of the traffic makes it critical to synchronize changes to application and network. • Key issues with Grid Computing include: • Instantiation of the connectivity with high data rates (100’s Gbps) and/or data set size (1000’s) • Controlling very high speed network Remote medical application adds more complexity over Grid Computing in that it requires fast setup of 100Gbps level of connectivity with higher security and more stringent jitter requirements including MP-MP connectivity. • Lambda-level optical transport with control plane would be required with a sophisticated path computation algorithm across layer. (Optical Bypass application)

14. Problem Statement The lack of common coordination mechanism between the application and each of the layers in the “network” does not allow coordinated cross-layer optimization: • Coordinated “query” of application and network requirements to determine available computing and network resources (including resource availability and demand as a function of time); • Coordinated provisioning processes (resource reservation) of both application and network layers based resource availability on both layers (statistical and/or real time); • Coordinated cross-layer monitoring; and • Quick re-optimization based on policy of the application/network upon churn

15. Existing Solutions Only Provide Partial Solutions • IETF Management solutions: SNMP, Netconf/Yang, • Do not provide the necessary context to view across multiple layers, multiple devices/technologies. • Lack of a context that allows synchronization of actions for read-view, write-view, notify-view and actions. • MPLS OAM • MPLS OAM is limited to MPLS device. The current scope of MPLS OAM does not support non-MPLS devices for its configuration and provisioning functions. • Lacks topology sharing and configuration interface. • ITU-T Y.2011/2012 • Defines application network interface (ANI); however, it does not address any details on cross-layer synchronization of information, configuration and provisioning • IETF ALTO WG • Current scope does not address the multi-layer synchronization problems • Does not provide the mechanism to configure/re-optimize and provision across layers.

16. Roll-forward, Roll-back For massive data or time critical Implies synchronization or Atomic handling SNMP Example Application Source End Point Consuming Resource End Point Consuming Resource Application Source CE CE Transport MIB Transport MIB Bridge MIB Bridge MIB PE Network Egress PE Network Ingress L2VPLS MIB- L2VPLS MIB- Bridge MIB L2 Core Transport Network L2 L2VPLS MIB- PE Data path Application Source Transport MIB

17. Potential Solutions

18. Cross-Layer Optimization Functions(Enablers) CLO functions: • To exchange network capabilities (Network Capability Exchanges) • To initiate service instantiation of application to network with profile exchange (Provisioning) • To exchange topology and/or traffic-engineering related information between the layers (Coordination ofcross-layer D/B’s for joint optimization) • To exchange application/network congestion/failure information (Coordination of configuration changes) CLO functions

19. CLO functions CLO functions Information sharing and CLO entity ownership • Information to be shared across layer depends on CLO ownership • CLO by application provider  Sharing of some type of topology information • CLO by network provider  sharing of some type of application information • Other possibilities include neutral 3rd party “broker” CLO Entity 3rd Party Broker CLO Entity

20. Generalized Data Path Connectivity (Single Domain) Application Source End Point Consuming Resource End Point Consuming Resource Application Source CE CE CLO Functions PE Network Egress PE Network Ingress Core Transport Network (L1 or L2 or L3/MPLS-TE) Data path

21. Multi-Layer, Multi-Device, Multi-Domain Scope of CLO Application Carrier 1 IP L3 Based Carrier 2 L2/SPBB Based Carrier 3 OTN/WDM OTN/WDM WDM (ROADM) Multi-Domain Adaptation and Translation Cross Layer Communication

22. Summary – Proposal to IETF Create an IETF WG to: • Define Cross-layer optimization functions and architecture • Develop protocols that would enable: • Information Exchange between Application and Network Layers • Topological and TE (Virtual/Abstract) view of each layers to be exchanged per query • Monitoring data exchange • Allow the Application Layer to request for a path estimation (path feasibility) to Network Layer • Allow the Application Layer to initiate a provisioning connection/flow to network layer • Multi-layer, multi-technology adaption and translation • Potential multi-domain

23. Thank You