Cross-Layer Optimization (CLO) Architectural Possibilities

1. Cross-Layer Optimization (CLO) Architectural Possibilities Greg Bernstein, Young Lee

2. Cross Layer Optimization(Rough Categories) • Planning • Service objectives, service size and scale • Service structure (architecture) – clients, servers, control points, etc… • Network topology and capabilities – connectivity and capacities • Determine service viability, level of service possible, “application placement problems” • Provisioning • Network and Application resource allocation • Network admission control and reservations • Application server and control point allocation and initialization • Monitoring & Adaptation • Network and Application Usage and Fault monitoring • Network and Application Re-optimization (client/server selection, etc.), Fault recovery/mitigation

3. Cross-Layer Optimization Functions CLO functions: • Exchange either or both network capabilities or application demand • To exchange topology and/or traffic-engineering related information between the layers • To initiate service instantiation of application to network with profile exchange (provisioning) • To exchange application/network congestion/failure information (monitoring) Capabilities Topology Provisioning Utilization monitoring Fault monitoring

4. Information used in Cross Layer Optimization • Application Layer • Client/Customer identification of some type, e.g., IP address. • Server types and identification • Application data flows and QoS requirements; These may be statistical in nature and vary over time • Server load and fault conditions • Network Layer • Network topology, client & server locations within that topology • Network capabilities and capacities with respect to QoS, etc… • Other possibilities include neutral 3rd party “broker” • Network load and fault conditions Application Network

5. Architectural Entities Application CLO Gateway (ACG) Accesses application related data and processes Communicates with Network Gateway Communicates with application CLO processes Provides information abstraction and access limitations to outside entities Network CLO Gateway (NCG) Accesses network related data Communicate with Application Gateway Communicate with network processes such as admission control, resource reservation, connection processing, etc. Communicates with network CLO processes Provides information abstraction and access limitations to outside entities Application Application CLO Gateway Network CLO Gateway Network Page 4

6. Information Sharing and Privacy • Information Privacy • Limit information flow; use abstraction, don’t provide full access to management or control planes. • Application CLO Processes • May need some type of network information, e.g., some type of topology information • Network CLO Processes • May need some type of application information, e.g., client and server identification • 3rd Party CLO • Uses both application and network info Application CLO Processes ACG ACG ACG 3rd Party CLO Processes Network CLO Processes NCG NCG NCG

7. Next Steps • Categorize, scope, and prioritize problem space to be addressed • Look for commonality and differences across: • Application areas and approaches • Networking technologies • CLO functions • Define architectural alternatives • Types of entities and their functions • Define potential interfaces and information flows • Between application and network CLO gateways and external entities • Between application CLO gateway(s) and application processes and data • Between network CLO gateway(s) and network processes and data