The TCP/IP transport layer consists of two main protocol options:
the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP).

TCP/IP needs a mechanism to guarantee delivery of data across a network and the transport layer handles this. In short the transport layer provides a service to the layer above it, the application layer.

The benefits of TCP error recovery cannot be seen unless the data is lost. Let’s say Bob’s web browser was to request information from Larry’s server,  if either transmission were lost (Bob’s request to Larry or Larry’s response to Bob), HTTP would not take any direct action, but TCP would resend the data and ensure that it was received successfully.

In the above example demonstrates a function called adjacent-layer interaction, which defines the concepts of how adjacent layers in a networking model, on the same computer, work together. The
higher-layer protocol (HTTP) needs to do something it cannot do (error recovery). So, the higher layer asks for the next lower-layer protocol (TCP) to perform the service, and the next lower layer performs the service. The lower layer provides a service to the layer above it.

TCP/IP defines a large collection of protocols that allow computers to communicate.

What is discussed in chapter 2 is very general in nature and will be gone into depth in later chapters.

TCP/IP defines the details of each of these protocols inside documents called Requests for Comments (RFC).

The TCP/IP model represented in column 1 of the table lists the four layers of TCP/IP, and column 2 of the table lists several of the most popular TCP/IP protocols.

The TCP/IP Application Layer

The application layer provides an interface between software running on a
computer and the network itself. The application layer does not define the application itself, but rather it defines services that applications need—such as the capability to transfer a file in the case of HTTP.

Important general concepts behind networking models: when a particular layer on one computer wants to communicate with the same layer on another computer, the two computers use headers to hold the information that they want to communicate. The headers are part of what is transmitted between the two computers. This process is called same-layer interaction.

Sorry about the delay of the next post in the network series, I’ve been busy working on a new website.

I have many interests and one is to show people how to make money online, I came across a program dealing in cash gifting. Cash gifting has been around for hundreds of years and back in the late 60’s early 70’s, it got a bad reputation when some yahoos turned it into an illegal pyramid scheme.

I checked out several cash gifting programs and picked out the one I thought was the best. A bunch of people got together and made a conference call to the IRS to explain what our system was about and make sure it was legal. I have a recording of that conversation and plan on adding it to my website in the near future.

You’ve heard the old saying, ask 10 IRS agents the same question and get 10 different answers. Well I decided to download the pertinent documents and read them for myself as well and those I have posted on my site for anyone to download.

Why I choose this program was that many of the programs had a $500 starting level, this program starts out at $150, allowing more people to get involved, and caps out at the $10,000 level. The back office and support are VERY impressive and NO selling or special skills are required.

Anyway, that’s what I’ve been doing the past week and why I haven’t posted the next part in the network series. I’ll be another week or so finishing the site then I’ll get back to studying and posting here.

In the mean time, if you have an interest in making money online, swing by my site and check it out. Here is the link: http://www.EnjoyFinancialFreedomToday.com/