2

I have an endless amount of books and websites at my disposal, but this question stays totally unanswered, or rather every author invests his own solution for this problem. It's even placed within different layers depending on which Wikipedia article you're just reading.

        TCP/IP
|--------------------|
| application layer  |
|--------------------|
|   transport layer  |
|--------------------|
|    internet layer  |
|--------------------|
|        link layer  |
|--------------------|

I assume in my question that we all agree that TCP/IP consists of four layers. Yes, I've seen different views on this as well. Mainly people adding a fifth layer at the bottom for the physical stuff or they added a fifth layer beneath the application layer, just to place TLS there.

As far as I understand the whole thing, TLS (and the old dying SSL), are situated in the application layer of TCP/IP and acting as a wrapper around other application layer protocols (e.g. HTTP). Further they act on behalf of e.g. TCP, but the protocol is merely sitting in front of the actual application protocol rather than in the transport layer and sharing the space with TCP.

Well, I'd love to hear a clarification of this maybe not so important problem.

  • 2
    If you understand the functionality and purpose of TLS, why the need to arbitrarily insert it into a model. The model is just that, an approximation of the real world, not the ultimate source of truth in the universe. – Brett Lykins Oct 26 '14 at 22:49
  • 1
    When I read this question, my first thought was that you're asking the Internet to answer your homework questions, thank you for confirming this. – Benjamin Dale Oct 26 '14 at 23:39
6

Given the 4-layer model you are working within, TLS would fall the Application Layer. The Transport Layer only deals with the connection mode between processes - TCP/UDP multiplexing and the like.

4

As far as I understand the whole thing, TLS (and the old dying SSL), are situated in the application layer of TCP/IP

Correct.

and acting as a wrapper around other application layer protocols (e.g. HTTP). Further they act on behalf of e.g. TCP, but the protocol is merely sitting in front of the actual application protocol

I don't know what 'wrapper around' or 'on behalf of' or 'in front of' mean. TLS operates as an application protocol layered directly over TCP, and other application protocols such as HTTPS operate over TLS.

rather than in the transport layer and sharing the space with TCP.

Correct.

  • "and acting as a wrapper around other application layer protocols (e.g. HTTP)." I think your wording is odd here. HTTP over TLS wouldn't mean TLS encapsulated(or "wrapped with") in HTTP, would be the oppsite. Much as GRE over IPsec is GRE going "over" an IPsec medium. – codey Oct 30 '14 at 1:57
  • @codey It isn't my wording, it's the OP's. All his terminology: 'wrapped round' and 'on behalf of' and 'sitting in front of', is poor and therefore confusing. – user207421 Oct 30 '14 at 4:22
  • Wording is from en.wikipedia.org/wiki/Transport_Layer_Security so don't bash me. The explanation at Wikipedia made sense for me, so I reused it. But many books are explaining it differently. If I had to explain it myself: HTTP to TLS, TLS to TCP, TCP to IP, IP to link layer and vice versa. In the end HTTP and TLS simply share their place in the application layer. How does this sound to you? Otherwise, how would you phrase it? – Fleshgrinder Oct 30 '14 at 9:28
  • @Fleshgrinder Nobody has bashed you. There are several problems with that article. I'll fix it presently. The only word that is necessary here is 'over'. HTTPS is HTTP running over TLS running over TCP, for example. – user207421 Jan 12 '16 at 18:20
-2

Actually, TLS (Transport Layer Security) is initialized in the transport layer and is ended in the application layer. It is must so that the data received in the application layer by the viewer is protected till the end.

  • Many thanks for your answer, do you have some prove for your claim? – Fleshgrinder Oct 29 '14 at 11:39
  • 1
    I don't know what you could possibly mean by 'initialized in the transport layer'. TLS is not contained in the transport layer in any way. It is implemented entirely in the application layer. – user207421 Oct 30 '14 at 1:16
  • I now find that this answer is inaccurately plagiarized without acknowledgment from a dubious section of the Wikipedia article dealing with OSI, so it isn't even answering the question, which is about the four-layer TCP/IP model, not OSI.. – user207421 Jan 12 '16 at 18:44

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