DATA TRANSMISSION
Data packets -
⭐
Data like images, videos are broken down into packets which make it easier to
transmit information. This is done by the TCP (transmission control protocol). It
involves routing which is finding the optimum (shortest) path between routers in order
to transmit data.
Packets → chunks of information called ‘payload’
Header:
- Destination IP address
- Sender IP address
- Packer number
- Error checking method
Payload:
- The actual data
Trailer:
- Additional error checks
- A notification to identify the end of a packet
Error checks:
⭐
Done to ensure corruption did not occur, which includes deletion of some data,
addition of data that wasn’t sent at first, modification in the data.
Packet switching:
The data is first broken down into packets, containing the sender and receivers IP
addresses, as well as packet number and error checking methods. Routers contain
routing tables which help them identify the closest router. Routing occurs where
packets hop between each router which is the closest and fastest direction (optimum)
depending on the internet traffic. Eventually, all the packets reach the receiver where
an error checking method like a parity check is done to see if any bits have flipped or
not. Any corrupted data can be requested to be resent. When all the data arrives, using
the packet number, the data is rearranged into its original form.
Data transmission:
Serial → singular bit is sent over one wire, one at a time
- Data arrives in order
- Cheap over long and short distances
- Less likely for errors
- Can get expensive over very long distances
- Very slow
Parallel → multiple bits are sent over multiple wires.
- Large quantities of data can be transmitted fast
