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The Need for A Network Resource Status Service IMIC Workshop 1999 Boston University

QuO. The Need for A Network Resource Status Service IMIC Workshop 1999 Boston University. John Zinky jzinky@bbn.com BBN Technologies GTE www.dist-systems.bbn.com/tech/QuO August 30, 1999. Specifying QoS Parameters is a Familiar Concern To Even the Youngest User. User-Level QoS.

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The Need for A Network Resource Status Service IMIC Workshop 1999 Boston University

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  1. QuO The Need for A Network Resource Status ServiceIMIC Workshop 1999 Boston University John Zinky jzinky@bbn.com BBN Technologies GTE www.dist-systems.bbn.com/tech/QuO August 30, 1999

  2. Specifying QoS Parameters is a Familiar Concern To Even the Youngest User User-Level QoS Size of Picture Sample Rate of Sound System-Level Requirements Mbytes of Movie File Type of Movie Player Access Speed of ISP CPU/Memory

  3. Distributed Objects with QoS Extensions is a Powerful Abstraction Layer on Which to Build Applications Applications for geographically dispersed, heterogeneous environments Collaborative Planning Simulation WorkFlow Distributed Objects are the first abstraction layer that unifies CPU, storage, and communications CORBA + QuO QoS TCP/IP • This interface needs to be hidden from applications • It is too complicated • It is changing too quickly RSVP Multicast Ethernet ATM

  4. ISP ISP Trading-Off Bandwidth, CPU and Storage is the Key to Creating QoS Aware Applications. • Storage is moving into the edge network • The Bandwidth bottleneck is at the edge of the network • Java Applets move CPU away from the servers to the client Client Server Web Node Web Farm The backbone network is getting faster, but dumber

  5. Client Object Client Object Client Object Network Client Object The QoS Problem: Who is in Charge of Managing QOS • QoS is well-controlled for some location of Client and Object • QoS is unruly across the network • How can we resolve this?

  6. Logical Method Call Object Application Developer Client ORB Proxy ORB Proxy Middleware Developer COTS ORB COTS ORB Network Client Network Server Simple Client/Server-Base CORBA Implementation Does Not Manage QoS in the Network

  7. Contract Contract Network QuO Adds QoS Control and Measurement Into the CORBA Remote Method Call Logical Method Call Application Developer Client Object SysCond SysCond Delegate Delegate SysCond SysCond SysCond Qosketeer SysCond SysCond ORB Proxy ORB Proxy Mechanism/Property Manager Mechanism Developer Specialized ORB Specialized ORB Client Network Server

  8. Network QuO Clients Connect to CORBA Objects using Functional and Quality Interfaces Functional Quality Client Interface Description Language Defines the Functional Interface Quality Description Languages Define the System Interface IDL QDL The Client sees NO change in the functional interface, I.e. the language bindings are the same A QuO Connection logically moves the object into the client’s address space QuO Delegate Client ORB Server ORB QuO helps spread the object’s functionality to the most desirable location; extending the strict Client-Server implementation of the object The QuO Connection integrates the individual QoS agreements for the Network, Client, and Server, by using a contract QuO Delegate Remote Object

  9. CMU REMOS is an Example of Network Configuration and Status Dissemination Service

  10. QuO Instrumentation Collects Resource Status and Measures Delivered QoS Measured QoS Expected QoS Client Object Correlate Probes Disseminate Delegate Delegate Infer Probes Probes Integrate Translate Piggybacked Measurements Collect QuO Gateway QuO Gateway Probes Probes Status Resource Resource Resource

  11. Configuration Information (Query-based) The expected Capacity between two IP addresses The expected MIP of the Client and Server computers Possible Caches at Client, Servers and Proxies Status Information (Subscription-based) Number Greedy Flow over bootleneck link Load Average of Hosts Available cache size Applications Need to be Aware of Available Resources

  12. Distributed Objects infrastructure is the place to make trade-offs between Bandwidth, CPU, Storage. A Resource Configuration and Status Service is needed to make these trade-offs The Network infrastructure must be involved with creating this service. Two levels of service are needed Query-based to get Configuration Subscription-based to get Status The service should be as Ubiquitous as DNS DNS is Administrative, not physical Conclusion: Resource Awareness is a Missing Service that should be offered by Networks

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