INTER-LAYER - Network to Network (N2N) Interoperability

If we take a look at the traditional seven-layer OSI model for computer networking, the network layer is conventionally located within the third tier, directly standing over data link layer (layer 2) and responding to the transport layer (layer 4). However, this is a reference model that with the birth of new radio access technologies and IoT protocols, has had to adapt to be compliant with the IoT reference layer architecture in order to involve a very heterogeneous range of devices and its protocols that are no based in the traditional networking model anymore. Hence, the network layer in an IoT architecture has adopted a wider sense.

INTER-IoT understands the network layer of an IoT deployment as the protocols, systems and devices that work on the layers 2 and 3, and even 4 in some cases, of the traditional OSI model. At this level we have to contemplate pervasive and ubiquitous networks aspects not commonly involved in traditional networks.

The particularity of IoT networks is the integration of different types of protocols. These protocols are adapted to the needs of the devices, usually constrain devices, and to the data types that communicate device information. Moreover, the integration of a new device in an already operating deployment becomes a difficult task. Also, the operations on highly constrained environments are also an important restriction to take in account.

INTER-Layer approach to network interoperability

As has been depicted. the great challenges that interoperability in the network layer must face is caused by the following problems:

  • Difficulty to manage big amount of traffic flows generated by smart devices.
  • Poor system scalability, with difficulties to integrate new devices.
  • Problems in interconnection of gateways and platforms via networks used by different providers.
  • Several devices with totally different radio network access have to be accessed from a single gateway as an AP.
  • Management of device's mobility through different access points.

Thus, one of the main approaches to face these problems is the virtualization of the network layer, providing an extra tier of abstraction that facilitates management, scalability, seamless support for smart objects mobility (roaming) and information routing. This will allow the design and implementation of fully connected IoT ecosystems.

Then, INTER-IoT describes network interoperability as the quality of communicate devices belonging to different networks or different sub-areas of the same network of an IoT deployment. Very often the use of really heterogeneous protocols (6LowPAN, RPL, LoRa, SIGFox, etc) and mechanisms (tunnelling mechanisms over IP, GRE and 6LoWPAN, etc) at IoT network level are problems we desire to solve. From there arise the necessity of create the proposed interoperability solution. INTER-IoT interoperability solution will be based on virtualization and software defined paradigms but mainly on two approaches: Network Function Virtualization (NFV) and Software Defined Networks (SDN), both working together to create interoperability at the core network. The capabilities implemented within the network layer to achieve this interoperability are summarized as:

  • Decoupling of data plane from logical plane using the well-studied protocol OpenFlow.
  • Virtualizing network services at the top of the architecture.
  • Implementation of techniques for traffic engineering to handle different flows of data generated by sensors depending on its priority.

These capabilities will be enabled using the most actual technologies available in the open source community, and extending its features to be adapted to INTER-IoT use cases. This solution involves the creation of a virtual SDN network using technologies as OpenFlow protocol, OpenVSwitch and a lightweight and flexible controller, in this case; RYU.

In order to aggregate and integrate all these tools to obtain the desired network infrastructure the following recipe: Recipe 1, will describe step-by-step the methodology to set-up and test a basic version of the INTER-IoT solution.

More information about INTER-IoT network layer interoperability can be found in the official deliverables and online documentation. Please, refer to Referenced section to find out more.