The TCP/IP Model is the implemented network protocol suite
of the internet, the OSI Model is now considered a theoretical
model because it was never caught on like TCP/IP but it has been a very
influential model. Cisco uses both the OSI and the TCP/IP models to talk about
how data is separated into pieces which are turned into smaller packages. This
process is called encapsulation which happens from Layer 7 down
to Layer 1. The encapsulated packets or packages travel across the network or
the internet and are rebuilt - decapsulation) at the receiving
host end. Decapsulation happens from the bottom up, Layer 1 to Layer 7
As data is built into packets or packages it is done in layers. By separating
the networking process into layers developers and engineers are able to isolate
the necessary functions for their products and not concern themselves with the
entire networking architecture. In this way, a layered approach and the rules
and protocols recommended by each layer, promote hardware compatibility, easier
software development, and competition. By clearly separating the role of each
layer networkers are able to easily troubleshoot network failures. It is common
for network technicians to identify a layer 1 issue as an unplugged network
cable. Similarly a computer which can ping an ip address but is unable to ping a
domain name is operating fine at layer 3 but is having an issue at layer 7. See
my video tutorials below for an explanation of network layer
characteristics.
