How BGP protocol belongs to Application Layer of OSI model?

Question

It is generally said that BGP protocol belongs to Application Layer of OSI model but how is this possible ?

It is made use of by border routers which belongs to level-3 then will that mean border routers are special kind of routers which act at application layer?

How do they differ from general routers?

Answer 1

When OSI refers to an application layer it does not essentially means the end system, BGP operates over the transport layer TCP on port number 179. It was defined in the RFC 1771.

Border Gateway nodes are intermediate nodes and the job is to find out the shortest path to reach an AS. I would suggest please go through the following video which should clarify the working

Comments

are the layers of OSI model physical or conceptual?

by this i mean whether each layer of OSI model is present in one or other physical form(like hardware or software) or is just simply logical(just for us to understand)?

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OSI is a model and designed by the fact of logical layers which can be present in the physical form also.

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then where is transport layer located if it is physical?

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Transport is over network layer??