Exactly. Generally speaking, the notion of a communication protocol stack refers to a layered architecture (e.g., "pile" or "stack") of protocols/services, the goal of which is to provide what appears to be a simple, consistent mechanism for communication between two or more endpoints, even when the endpoints are not homogeneous, and/or the connectivity between them is non-trivial.

Like other layered architectures, protocol stacks help manage complexity and promote versatility. In particular:

• Each layer in a protocol stack only uses the services of the layer immediately beneath it, and provides services only to the layer immediately above it. Thus, each layer in a protocol stack abstracts away the complexity hidden in layers beneath itself to the layers above itself.
• Each layer in a protocol stack may be easily replaced with a similar alternate layer, provided that layer has the same interfaces. For example, TCP can be readily replaced with the much simpler UDP in applications where the data integrity guarantees provided by TCP are unneeded.

As a side note, IP a network layer protocol. The primary role of IP is determining the path data should take to travel between local networks. It really does little more; it does not guarantee that data it sends will ever be received, and does not guarantee that data that is received is actually received in the order it was sent. TCP is a transport layer protocol. It effectively builds upon the services provided by IP to make sure that data is reliably delivered, and that the order of data receipt corresponds to the order of data transmission, among other things.

Networking is a complex subject, and a brief forum posting can hardly do it justice. For a high level introduction to the subject, you might want to read Computer Networking: A Top-Down Approach. For more of an electrical engineering perspective with a bottum-up view, try Computer Networks. Finally, for a detailed treatment of TCP/IP, see TCP/IP Illustrated (you might just want to start with volume 1), which is frequently regarded as the definitive reference on the subject.

You might also want to check out this reference that was recently mentioned in the forum:


I have not read it myself, but it looks like it contains some decent survey material, even if a significant amount of the publication is very high level.

--Sasha Jevtic