We finished our last post writing about the Transport Layer of the OSI Reference Model of the network. Now, I’m going to summarize the Internet & Network layers of such model.
Internet Layer.
The Internet layer primarily defines the Internet Protocol (IP) and defines IP addressing, so, that devices can have its own unique IP. In addition, the Internet layer defines the process of routing to let routers deliver packets of data to the correct destination.
The data encapsulated in the Internet layer is a called a packet.
Network Layer.
The Network access layer defines the hardware and protocols required to deliver data across some physical network. It includes all the variations of Ethernet protocols, PPP and Frame Relay.
The data including Ethernet header/trailer and PPP header/trailer in the Network layer is called a frame.
In a brief, the TCP/IP model consists of the following layers:
- Application
- Transport
- Internet
- Network Access
The next post of this CCNA crash course will about the OSI reference model of the network.
802.11
I was studying the book: “802.11 (Wi-Fi) Networking Handbook” by Neil Reid and Ron Seide plus a lot of user’s posts in forums… I did it mainly because my home network connection was very slow and because I wanted to improve my knowledge in wireless connections.
I realized that I made the right decision. I learned that my OpenSUSE wireless driver was not the cause of my slow connection… I just a few steps to tune up my wireless connection and I want to share with you a few tips to do it:
- Make sure that your wireless devices are using the same wireless protocol specification of your router.
- Look up for the best channel.
- Auto negotiate the speed of your device.
Also, consider that encryption reduces transfer speed in more or less factor; however, it’s best to loose a few bit/s than to be easily cracked.
TCP/IP and OSI are the two networking models that builds nowadays networks. A networking model is an organized of set of documents that describes functions required in a network.
We live completely relax about computers and mobile devices having communications among themselves. However, once upon a time, when there were no networking and every vendor made their devices to communicate only with others of their brand, this communication was hard to occur. So, it was necessary to create an open standardized networking model that all vendors would support. It gave origin to the design and development of the Open System Interconnection (O.S.I. model). A few years later, the U.S. Defense Department opened a contract to develop a new network model. Then, it was the origin of what was called the TCP/IP networking model.
TCP/IP architectural model and example protocols.
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| TCP/IP Architecture Layer | Example Protocols |
| Application | HTTP, POP3, SMTP |
| Transport | TCP, UDP |
| Internet | IP |
| Network Access | Ethernet, Frame Relay |
The TCP/IP Application Layer.
This netwokr layer provides an interface between software running on a computer and the network itself.
The TCP/IP Transport Layer.
The TCP/IP transport layer consists of 2 main protocols: the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP).
This post will be continued with more information about the TCP/IP layers, protocols involved as well as the OSI network model.
