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= Conducting Experiments in DETERLab =

DETERLab is regarded as a scientific instrument to 
create knowledge and understanding through 
observation and measurement of cyber security 
technologies. DETERLab provides a 
flexible software framework to 
structure the experiment environment 
and execute the procedue 
while ensuring experiment validity and repeatability. 
In this section we discuss each of these aspects in 
detail. 

== Environment ==

The experiment environment defines the set of 
resources required to configure a DETERLab experiment. 
It consists of three planes: 

* '''an experiment plane: ''' 

  The plane that carries the experiment traffic. 
  It consists of the set of experiment nodes, substrates,
  and their topological structure. 
  The functional behaviors are 
  mapped onto the experiment nodes.
  The structure is defined in the TopDL/ns-2 
  description file.


* '''a control plane: ''' 
   The plane to send and receive  control specific instructions and 
   signalling commands to the experiment nodes. 
   In addition to the experiment nodes, other control-specific 
   nodes such as an orchestrator and a bridge may also belong to the control plane. 
   The topological structure of the control plane 
   is defined by the testbed or configured per experiment
   in the TopDL/MesDL description file.
   The topology consists of directors, bridges, overlays, and orchestrators 

* '''a data plane: '''
   The plane to carry measurement specific traffic for 
   for analysis and visualization. 
   In addition to the experiment nodes, other data specific 
   nodes, such as aggregators and collectors, 
   may also belong to the data plane. 
   The topological structure of the data plane 
   is defined by the testbed or configured per experiment
   in the description TopDL/MesDL file.  
   The topology consists of sensors, collector, aggregators and queriers 

Each of the above plane may be combined 
due to resource constraints on the testbed. 

== Workflow ==

The experiment workflow defines the dynamic 
procedure enacted to conduct a DETERLab experiment. 
It consists of three main activities: 

* '''Event Streams: '''
    An event is a  signal to invoke a particular behavior on the experiment nodes. 
    The event streams in an experiment are 
    partially ordered set of events defined as a directed acyclic graph. 
    An experiment workflow consists on one or more event streams  
    defined in an AAL  description file. 
    All event signals are sent over the control plane 
    typically by the orchestrator. 

* '''Triggers: '''
    A synchronization point in the dynamic experiment workflow. 
    The trigger may be ''time-based'', that is the orchestrator waits for 
    a particular amount of time to lapse or ''event-based'', where the 
    orchestrator waits to receive a signal before proceeding with the 
    workflow. Triggers can be used to synchronize one or more event streams.
    All triggers are sent over the control plane.
    Triggers are defined as part of the experiment workflow in 
    the AAL description file. 


* '''Collectors: '''
   A signal to enable sensing and collection of experiment measurements for 
   feedback as 
   triggers and for analysis. 
   All sensing and collection measurements are sent over the data plane. 
   Collectors may be defined within the procedure description AAL file. 


== Validity Management ==

The experiment validity is maintained by a set of constraints and 
invariants asserted throughout the experiment lifecycle. 
They relate to the experiment environment and the workflow as follows: 

* '''Environment:'''
     During the process of defining and configuring the environment, 
     the constraints and invariants can be used to 
     ensure the validity of a particular configuration step. 
     Some constraints and invariants may indicate key 
     capacity requirements for validity, 
     for example, CPU requirements for experiment nodes,
     while some may be functional requirements, such as, 
     number of available client hosts.
     The constraints and invariants are defined in an ECL description file
     and processed by the DETERLab validity management framework. 

* '''Workflow:''' 
    During experiment execution, the constraints and invariants 
    can be used to ensure that the experiment proceeds in accordance 
    with these assumptions. The constraints can thus be used to ensure 
    ''safety'', that is, the experiment will not do anything bad and 
    ''liveness'' that is, the experiment will do something useful.   
    The constraints and invariants are defined in an ECL description file
    and processed by the DETERLab validity management framework. 
      
  


== Repeatability ==
 
Take a description, resolve it, and rerun it again and again