Changes between Version 43 and Version 44 of 2ndInstMeasWork

Timestamp:

07/18/10 18:34:16 (14 years ago)

Author:

fahmy@cs.purdue.edu

Comment:

--

2ndInstMeasWork

@@ -212 +212 @@
   *agreed to organize first discussion and writing
 
-Define an approach based on OMF/OML and S3:
-  HTTP(S)[[BR]]
-  REST vs SOAP[[BR]]
-  Authorization by credentials or ?  If credentials, how to revoke?[[BR]]
-  Pass XML fragments[[BR]]
-  Define basic API[[BR]]
+Most instrumentation services follow the following steps: (1) request,
+(2) measure, (3) process, (4) transport, and (5) retrieve. A user of
+the instrumentation service will request certain measurements, which
+results in the provisioning and configuration of measurement
+probes. The probes generate a set or a stream of measurement data
+which may be further processed and potentially transported to a
+different location. Finally, the results of the requested measurements
+are stored in one or more repositories from which they can be
+retrieved and/or queried by authorized users, tools and services,
+either immediately (real-time) or at a later time (history).[[BR]]
+
+Depending on usage scenarios and objectives, several different
+architectures for instrumentation and measurement can emerge.  Current
+GENI instrumentation projects leverage a number of popular tools to
+construct their service. For example, the Scalable Sensing Service
+project (S3) implements "sensor pods" (measurement points) as
+cgi scripts accessible through any web-server that supports cgi. Boa,
+a light-weight open source web-server, is currently used.  Therefore,
+starting/stopping the sensor pods is simply accomplished by starting
+and stopping the server.  This framework enables convenient third
+party measurements; that is, measurements between two nodes can be
+initiated by a third node.  Periodic measurements are configured as
+"cron" jobs on the sensor pods.  A sensing information manager ensures
+the liveness of the service using vxargs. The sensing information
+manager also collects the measurements from the sensor pods using
+rsync, and stores them in a data store (S3).[[BR]]
+
+In contrast, OML (OMLTridentCom,OMLwiki) takes a distributed
+stream-based approach. Probes are assumed to produce a stream of
+measurement tuples which are streamed through a configurable set of
+filters and caches to a repository. The repository, like S3, provides
+a web service interface allowing users and other services to retrieve
+the results (pull mode). However, users/services can also directly
+subscribe to a stream for operation in push mode. OML is integrated
+into the OMF control framework to simplify configuration of the entire
+distributed setup, as well as provide to support for "steerable"
+experiments, where the orchestration of an experiment can be
+influenced by the simultaneously collected measurements.[[BR]]
+
+Another instrumentation service currently in GENI is perfSONAR, which
+sits somewhere in the middle. Various distributed monitoring services
+are "wrapped" into individual web services called "Measurement Points"
+(MPs) which return their results using the Open Grid Forum's Network
+Measurement Working Group (NMWG) XML schema. A set of other services,
+such as the Measurement Archive, Lookup, Authentication, Topology,
+Transformation, and Resource Protector provide a comprehensive suite
+of services.  perfSONAR is migrating to Representational State
+Transfer (REST), viewed as a lighter-weight service-oriented
+architecture over existing web service technologies, e.g.,
+SOAP. XML-RPC and SNMP are also leveraged in several current
+measurement projects.[[BR]]
+
+APIs[[BR]]
+
+There are essentially two types of measurement APIs: one concerning
+itself with the configuration of the various elements and services
+participating in the measurement and monitoring activities, and the
+other facilitating the transfer of the measurement data itself.[[BR]]
+
+The provisioning and configuration of instrumentation functionality in
+a large federated environment serving many experimenters and spanning
+many countries with their respective legal frameworks is clearly a
+complex undertaking.  However, at a fundamental level, instrumentation
+requires discovering, provisioning, and configuring resources, within
+the constraints of policies and user privileges. This is essentially
+functionality that the GENI control framework (CF) is (or will be)
+providing.  What is not covered by the CF is the protocol for encoding
+and transporting measurement data between entities. Here, we must
+differentiate between two types of operations: the push or streaming,
+and the pull or requesting mode of operation. Both are not unique to
+this domain and there are several standards and widely used solutions.[[BR]]
+
+OML will soon be using the Internet Protocol Flow Information Export
+(IPFIX) protocol standardized by the IETF for streaming measurements
+from an exporter to a collector. perfSONAR, as discussed above, is
+using SOAP and the Open Grid Forum's Network Measurement Working Group
+(NMWG) XML schema for returning measurements back to a requester.  In
+OML, once an application has been modified to integrate OML
+measurements, two possible configurations are possible: passing
+general arguments on the command line of the enhanced application, or
+using an XML configuration file. The XML configuration file allows
+the user to multiplex the measurement stream and apply different
+filters inside the application and between Measurement Points
+(OMLTridentCom,OMLwiki).[[BR]]
+
+
+References:[[BR]]
+
+(S3) P. Yalagandula, P. Sharma, S. Banerjee, S. Basu, and S.-J Lee.
+S3: A scalable sensing service for monitoring large networked
+systems.  In Proceedings of the ACM SIGCOMM Workshop on Internet
+Network Management (INM), Sept. 2006.[[BR]]
+
+(OMLTridentCom) J. White, G. Jourjon, T. Rakatoarivelo, M. Ott.
+Measurement Architectures for Network Experiments with Disconnected
+Mobile Nodes.  In Proceedings of TridentCom, 2009.[[BR]]
+
+(OMLwiki) http://omf.mytestbed.net/wiki/oml/Documentation
+
+
 
 ===  Topic 6  GENI I&M  Interfaces and Protocols (APIs):  Data Flows and Data File Transfers ===