JOLNet: a geographical SDN network testbed

The JOLNet experimental testbed aims to deploy an SDN geographical overlay network facility, in order to extensively and concretely assess the SDN technology and its operational impact. As a matter of fact, initial introduction of some SDN tools has now been actually finalized, albeit mainly with a short term and focused approach, in limited network context and to address specific problems. However, besides its promises, a longer term generalized SDN adoption in production networks – i.e., a whole multi-service network built around SDN – still brings a quite disruptive potential and therefore represents a big challenge. He software archieture of JolNet is represented in Figure 1


Figure 1– Jolnet API exposure

Along with many architecture open issues, its impact on Carrier’s organization, network operations practices and processes is still to be fully understood and assessed. The trial implementation of an «open» experimental network testbed will allow to concretely assess the key SDN technologies. The JOLNet facility, due to its openness, represents also a vehicle to experimentally assess new future-oriented solutions and improvements in many technical areas, including: network virtualization technologies, SDN controllers, network and service applications, end-user SDN-enabled applications. Moreover, the adoption of the OpenStack framework in JOLNet is key to investigate the synergies between SDN and NFV and the integration of a “distributed Data Center” with the geographical network environment.

In order to achieve maximum flexibility, allowing partners to interoperate and program the network in any feasible way, the Jolnet architecture exposes APIs at any level (see Figure 4), from data plane, where application can directly interact in order to change forwarding tables or low level routing protocols, to control layer with new network appliances declaring requirements in term of data path, QOS, computational elements and resources, storage that the Jolnet framework should compile in real behaviors.


Figure 2 – Jolnet Points of Presence

The JOLNet infrastructure foundation is based on Telecom Italia Lab (TILab) network, whose branches are in all the TILab sites that are part of the JOL (Joint Open Lab[1]). The experimental testbed infrastructure has a physical star topology on which a JOLNet logical topology can be designed in a very flexible way. We start with a full mesh topology among the 6 JOLNet PoPs (Phase 1). Each of the PoPs is provided with two OpenFlow-capable nodes: one access node acting as a CPE device for the users and one node forming the network backbone. If needed, the topology may be further enriched by instantiating more logical OpenFlow switches in each site. Besides the network resources, the PoP also includes a thighlty coupled virtualization server: the several Virtual Machines (VM) are used to run JOLNet system components, such as: virtual router, network virtualization (e.g. FlowVisor), SDN controller, buth they are also available to instantiate VMs to run user-defined applications in their own slices.

Some key technical areas for experimental investigation on an experimental facility like the JOLNet include: IT and TLC Network integration, distributed vs. centralized control architecture and controller interworking, network applications development, NorthBound API definition, hybrid network models deployment. Furthermore, the testbed aims to stimulate the development of new tools to be used in future SDN networks, along with new “network-aware” applications, able to take advantage from a tighter interaction with the network.

Specific experimental research topics proposed to be run on JOLNet include:

  • Advanced network virtualization techniques (overcoming the limitations of current FlowVisor model)
  • Distributed controller architecture for resilient transport networks, in a hybrid IP/SDN scenario
  • Scalability analysis of OpenFlow controllers
  • Performance analysis of a controller under DoS attacks
  • Evaluation of the OpenDaylight framework and tools
  • Stateful Path Computation for the distributed controller IP/SDN transport network scenario
  • Performance of OpenFlow network enabling user programmable data plane services
  • LISP-based mobility on a OpenFlow/OpenDaylight network
  • SDN-enabled EPC (Evolved Packet Core)
  • Cooperative provisioning of network and cloud resources and services in a multi-domain scenario
  • Monitoring and dynamic adaptation of resources for energy saving and green networking
  • Network application to enable rapid VM migration between DCs
  • Load-friendly bulk data transfer mode
  • End-to-end multipath techniques for cloud services

[1] The JOL initiative is a research partnership started by Telecom Italia with five prominent Italian universities hosting joint laboratories addressing cutting-edge technological innovation research topics.