Are ports/sockets considered layer 4?

m00ndogg

What layer are ports & sockets?

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Comments

networker050184

So what is your understanding of layer 4? I think if you get that down pat you'll answer your own question.

m00ndogg

Thanks for ...
I believe that they are layer 4, but someone is trying to tell me that they are layer 5.
I am only trying to get a definitive answer from someone smarter than me.

fuz1on

You guys are both right - L3-L7.

steele84

Transport is how I remember.

LS1

I guess as long as you're not referring to network ports in a wall socket, then I think you're good

m00ndogg

I like that!
So ports are definately layer 4.
What about sockets? Same?
I would think so but would love to hear someone else say so!

Nans

m00ndogg wrote: »

I like that!
So ports are definately layer 4.
What about sockets? Same?
I would think so but would love to hear someone else say so!

A TCP socket is an endpoint instance defined by an IP address and a port in the context of either a particular TCP connection or the listening state.
A port is a virtualisation identifier defining a service endpoint (as distinct from a service instanceendpoint aka session identifier).
A TCP socket is not a connection, it is the endpoint of a specific connection.
There can be concurrent connections to a service endpoint, because a connection is identified byboth its local and remote endpoints, allowing traffic to be routed to a specific service instance.
There can only be one listener socket for a given address/port combination.

To be specific about what layer they are sockets help you identify the sessions or to separate the data from different application's which gives me a feeling that that they belong to layer 5 too. But usually they are mostly discussed in layer 4 transport

m00ndogg

Great info there Nans!!
Thanks for that...

theodoxa

A TCP or UDP Port is Layer 4 (Transport Layer). A Socket is a combination of a Layer 3 (e.g. IP) Address and Layer 4 Port, so I would say it is both Layer 3 and Layer 4.

Layer 5 is the Session Layer. It is responsible for establishing, maintaining, and tearing down Sessions. The Session Layer would establish sessions between sockets, but the Socket itself would be Layer 3/4.