OSI model
- Application generates a packet to be sent on the network and send it to layer below.
- The next layer is called as transport layer which manages end to end
communication between two machines. The protocol used can be TCP or
UDP. What is difference between these two protocol is another subject
altogether.
- Once packet is formed at transport layer, it is sent to network
layer which adds source and destination IP in the packet.Most important
field which is added at IP or network layer is Time To Live (TTL) which
is used by intermediate routers/switches to decide if packet needs to be
forwarded or not. (How destination IP is found?)
- After network layer, packet reaches data link or MAC layer, where
source and destination MAC address of machines are added. We will see
how these fields change between every two neighbors. (How destination
MAC is found?)
- Data link layer push this packet to physical layer where it is sent as stream of “0” and “1” on physical medium available.
