revision tcp ip part 1

REVISION OF TCP/IP
=================

==> IP transports datagrams (packets) from the source node to the destination node.
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TCP      (header size= 20 bytes)
===
TCP provides a connection-oriented reliable service for sending messages.
- splits a message into packets
- reassembles packets at the destination.
- resends packets that were lost in transit.
- it does error control.
- everything is in an order.

eg. Whatsapp
>hi
>mo
>sup
>?

UDP      (header size= 8 bytes)
===
UDP is connectionless, unreliable service for sending datagrams.
- message is small enough to fit into a packet.
- simpler (and faster) than TCP.
- never splits the data into multiple packets.
- does not care about error correction.
- does not maintain an order
Eg. Instagram

>mo
>hi
>?
>sup
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IP layer
========
==> IP layer provides a connectionless, unreliable delivery system for the packets.
    - each packet is independant of another.
    - IP layer does not maintain any history
    - Each IP packet must contain the Source address and the destination address.
    - does not guarantee the delivery of the packets.

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TCP header size - 20 bytes
UDP header size - 8 bytes

IPv4 size - 20 bytes
IPv6 size - 40 bytes