Tuesday, December 12, 2017

Federated Experiments

The physical interconnection among the available FLEX testbeds makes use of the GEANT network. All of them are academic institutes, and thus their connection to the Internet is facilitated over the GEANT network. Nevertheless, dedicated Layer 2 connections are used from each testbed directly to the other, in order to make use of an end-to-end isolated channel, by employing virtual circuits. These circuits are usually terminated as a VLAN interface at each testbed end. Nevertheless, since in many countries the connection to the GEANT network and subsequently to another testbed site requires a subscription service, the respective partners in FLEX have utilized only one link to the IMEC testbed. From there and through the automatic VLAN stitching process of jFed, an end-to-end link can be instantiated and provided, for example from NITOS to University of Malaga. For the setup of such an experiment, the jFed user has to use one node from w-iLab.t testbed and configured as a router interface, and subsequently connect it with two "dedicated external network connections" configured as the two testbeds that he/she wants to use (e.g. in the figure NITOS and UMA).

 

jFed Physical Interconnection 

 

jFed Based Reservation

As the work in FLEX in terms of the resources reservation, authorization and access is extending the existing work established under the Fed4FIRE umbrella, the FLEX-introduced resources have been respectively described, in order for the existing tools to be able to handle requests for them. The FLEX resources regard either LTE networks (base stations and EPCs), LTE UEs (USB dongles and Android Smartphones) and Software Defined Radio (SDR) devices, that are interoperable with the OpenAIrInterface platform. The tools we refer to is mainly the jFed tool and other reservation control mechanisms (e.g. NITOS Scheduler, imec w-iLab.t reservation tool), used for gaining control over the resources, by either a reservation through a calendar based GUI for the future, or via direct swap-in if the resources are idle and not used by another experimenter. For FLEX, we advertise each LTE network as a pair of eNodeB and EPC, though the handling EPC may be changed by jFed during the reservation of the resources. You can start your experiment by dropping an LTE network connection on the canvas. Configuring this connection brings up the following interface, as listed below:

NITOS jFed Setup

Configuring the femtocell supports a number of different parameters. You can use the RSpec editor on jFed to configure the LTE network parameters. These parameters are translated through each testbed’s brokering service to the commands for the LTErf tool, used for managing and handling the base stations and the EPCs. Hence, for any default pair of eNodeB and EPC at each testbed, a new “LTE network” entity is present at the jFed tool that can be configured and used. In Figure 4, the respective RSpecs for the eNodeBs. Any of the advertised values apart from the vendor and model name of the femtocell can be configured during the reservation process, by changing the parameters on the RSpec file of the experiment. Below are some of the parameters that are listed in the RSpec and are supported by the NITOS broker to be changed before the experiment.

 

NITOS eNB RSpecs

 

NITOS UE RSpecs

 

Federation Use Case - NITOS - w-iLab.t

The following experiment use case can be built entirely through jFed. We employ the mobile nodes of w-iLab.t testbed, with the EPC of the NITOS testbed. The intercommunications of the different entities takes place over GEANT. You can start by loading the following RSpec onto jFed. By hitting run on jFed you will see the experiment starting and the nodes being configured. A complete walkthrough on the process can be found here.

jFed Federation case

 

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