Question

Why do think understanding the OSI Model is important from a work standpoint? Give an example.

Answer 1

OSI Model was the 1st and still the “cleanest” global approach in trying to split a very complex set of problems to manageable and coherent sub-problems.Usually in present context knowledge of OSI layer is required in troubleshooting network related problems. I think it was, and is a success story in that respect. My great frustration is that the very well developed ISO OSI protocols never became a real-life culture but were left to shrink in the favor of the rather messy family of TCP/IP protocols that need continuous maintenance and patching still today.

OSI model is important because of its features like :

1. OSI model enables us to easily understand the big picture of network.
2. OSI models we can understand how hardware and software work together.
3. Thrrough OSI models we can understand new technologies as they are developed.
4. Through OSI models troubleshooting is easier by separate networks.
5. OSI models can be used to compare basic functional relationships on different networks.

However, the OSI reference model could also be said to be unimportant as there are no longer any current products that actually use this model. The only one I recall was DECNet long ago, although there were probably others.

Example:while connecting to the neighbor system

First, you want to communicate with your neighbor system, you need a physical connection.

i.e Cables, coax—-> Physical layer

Even though you are connected physically, you need to address yourself.

i.e MAC —-> Datalink Layer

MAC is a Physical Address for your device through which devices in a network identify yours.

Basically ethernet, wifi, wimax etc…

Now you have a MAC and Physical connection, all you need is a logical address

i.e IP —-> Network Layer

IP of a system is not permanent, when you use DHCP or when your ISP uses DHCP.

It is a temporary address given to your system. You can have a dedicated IP for your system, that costs you.

Now, you have a good setup of network with physical links and address but how do you communicate?

All you need is a protocol which transfers data from your system to another.

i.e TCP, UDP —-> Transport Layer

There should be an intermediate node which manages the setting up and taking down of the association between two communicating end points that is called a connection.

i.e SIP, RTP —-> Session Layer

The data that flows in a network will be in the form of 1’s and 0’s, so there should be a node which translates those 1’s and 0’s to plain text (human readable format) and if necessary compression and decompression. This is done by presentation layer

i.e Jpeg Mpeg —-> Presentation Layer

Finally, What you see in your monitor is the final application and the result of the combination of all these protocols.