Comparing the OSI model (7 layer) to the 5 layer model, have been asked a question that seems illogical

Thread Starter

NeilG71

Joined Dec 9, 2022
2
I have designed a network as part of a school project. It is an Ethernet, pretty standard. A few hubs per floor, hits a router in the closet, backbone up to the equipment room etc. One of the prompts for some discussion is asking whether this is a layer 7 or a layer 5 network or both? Seems sort of ridiculous to me unless I am misunderstanding things. One does not set out to build a "layer 7 network" or a "layer 5 network" right? It is more of a conceptual model, the 5 layer model essentially combining the top three of the 7 layer model. Has anyone ever tried to order a network card and been asked to choose whether it is for a layer 5 or layer 7 network? I think not. "hello, tech support........yes........yes.......ok well you need to set the network dip switch to 7 layers instead of 5....yes...ok..please fill out a short survey?.....-click-"
I guess the answer could be both? or "depends on how you want to look at it".
 

WBahn

Joined Mar 31, 2012
27,893
I would tend to agree with you. That would seem particularly true at the level of your hubs (why hubs and not switches?) and routers, which is where the two models are in pretty strong agreement.
 

Thread Starter

NeilG71

Joined Dec 9, 2022
2
I would tend to agree with you. That would seem particularly true at the level of your hubs (why hubs and not switches?) and routers, which is where the two models are in pretty strong agreement.
Thanks,
Yes, they are actually switches in my drawings, Cisco 110-24t's in fact.

This is the prompt:
  • Explain if this infrastructure has been built on a 5-layer model, an OSI 7-layer model, or both. Provide a rationale.

It has an SD-WAN hooking up a couple other facilities, AT&T business fiber Internet, etc, so it spans all layers. Even some applications specified.
I think I am going to just talk about the protocols, vs where they operate etc., make the case that it could be looked at either way. I have an associates in Data Com from 22 years ago, though I never worked that into a career change. I did change careers about 5 years ago and there is some opportunity to work on some industrial process control systems. This class is part of an Information Technology bachelor's program. Hopefully the bachelors might help me get a controls position next time one opens up, I am getting the practical experience now in any case. And if not, it gives me something to do during the slow hours when everything at the plant is running well.

Thanks again,
Neil
 

WBahn

Joined Mar 31, 2012
27,893
Since it has some applications specified, that is where to focus on. Is there anything in the spec or the design that would hint at a delineation between Session, Presentation and Application functions?
 
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