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  • NESTOR : NEtwork Self managemenT and ORganization
    and the configuration of network backup services Another example is the IP interface configuration of every node connected to a switch must match the VLAN configuration active on its port The current implementation of CDL is based on the Object Constraint Language OCL OCL was developed as part of the Unified Modeling Language UML standard it order to formally define the semantics of the UML Unlike OCL statements CDL separates the object model from the constraint definitions for two reasons First the most interesting constraints are the ones that make statements about the configuration of multiple RDL interfaces In such cases it may not be clear which object should own the constraint For example the aforementioned backup constraint is as much a property of the user account as of the backup service Second the same manager will not always perform model authoring and constraint authoring Device and service models will usually be obtained from the vendor or may be bundled in some standard model package Attaching domain specific constraints to RDL interfaces will limit the sharing of these models nestor IpHost allInstances select h h hostname null forAll h1 h2 h1 h2 implies h1 hostname h2 hostname The simple CDL constraint mentioned earlier is shown in the above figure The constraint states that for all object instances implementing the RDL interface nestor IpHost those who have a non null name should all have different names In the OCL syntax the right arrow operator operates on collections of objects sets bags and sequences The allInstances operator iterates over all classes implementing a particular interface Select is an operator that filters out elements in a collection that do not satisfy the boolean expression condition In this case select will remove all IP hosts that have a null name Finally the forAll operator states that for every pair of IP host instances the following boolean expression on the remaining IP host instances must be valid if two hosts objects are different different instances then their names must be different NESTOR Architecture and Operations The overall architecture of the NESTOR system is depicted in the figure below In the top layer Managers perform network configuration by accessing and manipulating data in a unified object relationship network model A systems administrator or a software agent may play the role of a Manager Systems administrators may interactively access the repository through a graphical or text based user interface tool or they may execute scripts or programs tailored specifically for a particular task NESTOR Managers access the repository using the Directory Access Protocol DAP a remote interface permitting Managers to execute either locally or remotely The Resource Directory Server RDS maintains an object repository that stores and controls access to model object instances Repository objects reflect configuration settings at the real network elements plus meta information that is supplied or inferred from multiple sources For example a model object representing a network host may contain information instrumented from the host such as network interface configuration meta information

    Original URL path: http://www.cs.columbia.edu/dcc/nestor/ (2016-02-17)
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  • Pegasus: Embedded Training Technologies
    of experiences An operator of a complex system typically activates responses to emergent scenarios and coordinates the interpretation of the scenario and the responses with other individuals involved in the operations of the system The problem of training in its broadest form is that of teaching operators to activate the best responses to emergent scenarios and pursue the best coordination procedures A typical system for which embedded training is applicable is broadly depicted in the figure above The system interacts with an external scenario through respective monitoring and control instrumentation of sensors black arrow and effectors red arrow It processes the scenario data acquired by the sensor instrumentation presents it to operators black arrow and acquires their response control actions red arrow to handle respective actions on the scenario For example consider a complex weapon system The scenario to which the system responds is defined by a battlefield situation Sensors acquire various parameters of the scenario process these and display data to the operators of the system The operators respond by activating certain functions which in turn cause effects on the scenario such as shooting a missile or a bomb In order to train operators it is necessary to present to them simulated scenarios acquire their responses and simulate their effects on the scenarios These activities can be accomplished by incorporating embedded training software as investigated by Pegasus It is also necessary to evaluate operators responses identify improvements and generate scenarios that improve operators performance The primary idea underlying the embedded training architecture is to augment the monitoring and control instrumentation of the target system with instrumentation to support training mode and then attach this instrumentation to the Pegasus training server This permits the Pegasus server to access the instrumentation of the target system and a create simulated scenarios b

    Original URL path: http://www.cs.columbia.edu/dcc/pegasus/ (2016-02-17)
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  • QoSME by Phil Wang
    the QoSockets extensions to the sockets mechanisms for QoS reservation and management QoSockets automatically generates the instrumentation to monitor QoS It scrutinizes interactions among applications and transport protocols and collects in QoS Management Information Bases MIBs statistics on the QoS delivered The main advantages of QoSockets are the following 1 Support of single API for transport layer QoS negotiation connection establishment and data transmission and of single API for OS QoS negotiation 2 Support of a single QoS negotiation protocol 3 Generality across application QoS needs 4 Automatic management of application QoS needs QoSockets are available for Solaris and Linux and support RSVP ATM adaptation ST II TCP UDP and Unix native protocols DOWNLOAD QoSockets Solaris 2 x version for SPARCstation with examples Linux 2 0 version for X86 PC with examples RSVP Release 4 2a3 Linux sources and binaries in TAR format gzipped Solaris sources and binaries in TAR format gzipped RSVPD binary Linux only PUBLICATIONS P Wang Y Yemini D Florrisi J Zinky and P Florissi Experimental QoS Performances of Multimedia Applications P G S Florissi QuAL Quality Assurance Language Ph D Thesis P G S Florissi and Y Yemini Management of Application Quality of Service P G

    Original URL path: http://www.cs.columbia.edu/dcc/qosockets/ (2016-02-17)
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  • VAN-Home
    vs treat the network as a best effort packet transport wire to best support their needs Third MENAs may perform dynamic vs vendor pre defined application layer vs network layer functions at edge nodes As an illustrating example a web caching application has many components deployed at edge nodes in order to provide coverage for certain network areas it may configure its components with certain topology e g a ring for increased reliability and may require guaranteed node and link resources in order to process and transport cached contents and it performs application level URL routing and cache management MENAs thus represent a new class of applications requiring new network services difficult to accomplish with current network services and APIs Application Program Interfaces The Virtual Active Network VAN architecture is an application middleware architecture to support the needs of multi edged network computing The VAN architecture allows MENAs through abstractions to deploy their service components in a VAN with desired service type caching filtering etc topology feature coverage and connectivity resource constraint processor cycle and link bandwidth and reliability constraint number of virtual links traversing a physical link The VAN architecture dynamically construct the requested VAN by employing algorithms to

    Original URL path: http://www.cs.columbia.edu/dcc/van/ (2016-02-17)
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  • NetScript

    (No additional info available in detailed archive for this subpage)
    Original URL path: /dcc/netscript/ (2016-02-17)


  • MarketNet main page

    (No additional info available in detailed archive for this subpage)
    Original URL path: /dcc/marketnet/ (2016-02-17)


  • Isochronets: a High-Speed Network Switching Architecture
    synchronized to reflect latency along tree links Synchronization is per band size which is large compared to frame transmission time It can thus be accomplished trough relatively simple mechanisms Furthermore synchronization errors can be easily accommodated Routing along a green band is accomplished by configuring the switches to route frames on incoming tree links to the appropriate output tree links for the duration of the band A source sends frames by scheduling transmission to the green bands of its destination In similarity to circuit switch or burst switch networks green bands allocate reserved network resources However the units to which resources are allocated are neither point point connections not traffic bursts but routes Routes represent long lived entities and thus processing and scheduling complexities can be resolved over time scale much longer than latency Scheduling transmissions to the green bands of the destination offers the basis for synchronization of the end nodes to the network operation Isochronets can be used to signal periphery nodes when destination becomes available leading to a novel transfer mode called Loosely synchronous Transfer Mode LTM The same signals can propagate through protocols at any layer and enhance their functionality The resulting Synchronous Protocol Stack SPS can support novel application with stringent synchronization requirements Isochronets offer several advantages Scalability with respect to transmission speeds Conversions of frames from optical to electronic representation in order to be processed is not required Provision of tunable guaranteed QoS of end end transport Protocol independence Internetworking is reduced to media layer bridging Minimization of processing and queueing latency in the transport path Support for asynchronous synchronous and isochronous traffic streams Efficient interfacing with end nodes Bandwidth heterogeneity is accommodated Status The following is a list of the on going research in Isochronets Design of the Isochronets architecture that includes the

    Original URL path: http://www.cs.columbia.edu/dcc/research/isochronets/isochronets.html (2016-02-17)
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  • People in the DCC Lab
    Research Associates Danilo Florissi Lab Administrator Susan Tritto Graduate Students Alexander V Konstantinou Gong Su Recent Alumni Patricia Gomes Soares Florissi German Goldszmidt Jakka Sairamesh Apostolos Dailianas Sushil da Silva

    Original URL path: http://www.cs.columbia.edu/dcc/people/ (2016-02-17)
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