The number of layers will depend on the model you refer to. The ISO/OSI model defines 7 layers. You can also use those 7 layers when examining the Internet protocol way of doing things, but the upper layers become collapsed into one.

You can find many good descriptions of the protocol layers online, by just searching under "ISO/OSI protocol layers." My short answer to your main question is, the IoT would have to involve all of those layers.

Here's a brief description of the 7-layer model:

1. Physical layer: the physical medium, such as twisted pair or a type of fiber optic cable, and the way bits are represented on that medium.

2. Data link layer: the protocol to gain access to the physical layer, and the way data frames are arranged and used, on that physical medium.

3. Network layer: that describes, for example, the IP datagram, how they are formatted, addressed, routed. The network layer is a way to allow communications to occur among just about any different types of physical networks. For instance, IP datagrams can flow from Ethernet to WiFi to ATM networks, over SONET or DSx telco links, over satellite links, and so forth. Same IP datagram wrapper can carry packets through and between any number of network technologies.

4. Transport layer: this layer allows different types of end to end links to be created. For example, you can establish a two-way connection, "error free," which seems very much like a connection-oriented telephone link, or you can establish less rigorous end to end links. This layer also does the error checks, end to end, and even error correction in some cases.

5. Session layer: this is how the end to end connection becomes established. In some cases, it can be very simple, almost non-existent, such as when broadcasting frames.

6. Presentation layer: the way parameters are formatted and defined.

7. Application layer: interface to the application program.

The Internet model essentially collapses layers 5-7 into one. In practical reality, the software that comes with applications incorporates every task that layers 5-7 must do.

So, from that description, I would say that IoT would involve all of the layers. Even simple devices, such as thermometers or switches, need the services of these layers, to be useful in an Internet setting.

Dear Mohammad,

Colleague Albert added a satisfactory answer. More elaborate IOT layer architecture is given in detail in the paper of the attached link: https://arxiv.org/ftp/arxiv/papers/1708/1708.04560.pdf

Best wishes

The ISO/OSI model is a great basis to divide "things". Digging deeper you may find out that the upper layers can be divided into sublayers to ease overview.

https://en.wikipedia.org/wiki/OSI_model is a good point to start with.

Dear Muhammad Esmaeili,

The detailed answer is already given by Mr. Albert. Whether you follow OSI or TCP/IP layered model, fundamental principle that must be kept in mind is that at any layer the protocols (communication/networking and/or application protocols) should all be made energy efficient and optimized considering the constrained nature of IoT devices.

Specifically, if you want to read about IoT architecture for multimedia communication, then following publication Article Internet of Multimedia Things: Vision and Challenges

best regards,

This is a good reference explaining the suggested layering architectures of IoT recently:

https://www.slideshare.net/mustafasadiqeng/internet-of-things-a-survey-on-enabling-technologies-protocols-and-applications-81868406

but in some papers what i read was perception layer,transportation layer,application layer.is it right?

then in which layer we will do edge computing in osi model?could you differentiate edge and fog computing? name some opensource tools to work in edge computing?

Sasi, I know that there is a tendency, for every new use case, to create a different set of protocol layers. I've even seen this done for digital TV! But I mostly object to this unnecessary form of "creativity," when dealing with something that works over the Internet. I just don't find it helpful. It leads people to believe that this IoT is something fundamentally new, when it is not. In my opinion, it is much easier to understand new concepts when they are addressed as an evolution, or as a special case, of what came before.

Unfortunately, once that new language becomes entrenched, we are all more or less forced to at least understand how it fits.

In this case, for example, the "perception layer" is something that would otherwise be part of the application program, and that single "transportation layer" is too aggregated to be of much use. The IoT is expected to operate over Internet networks, so as such, the 7-layer model still applies (even if layers 5-7 are aggregated).

The "perception layer" is where "data from multiple sensors is collected and converted to digital." Well, that's fine, if a special-purpose layer is required to explain something that applications have always done in the past. In fact, applications can do that and any number of other tasks.

I think it's more important to understand the bigger picture, rather than being misled into thinking that IoT is a whole different animal.

Dear Albert,

Thanks a lot for your kind reply and valuable answer.