if there are many paths in a big network deciding which way to direct the traffic is done by the switching
switching provides a feel like one-to-one connection

divided into 3 categories
1.Circuit switching
2.Message Switching
3.packet switchng subdivided into (i)datgram approach (ii)virtual circuit approach

1.Circuit switching:
before seding data,A dedicated path is stablished between sender and reciever
there are 3 phases in this switching technique
phase-1 connection establishment
phase-2 data transfer
phase-3 connection disconnection

ex:telephone network

2.Message Switching

In this switching message is transferred as complete unit and then forward using store and forward mechanism at intermediary nodes at intermediary nodes message is broken into pieces

3.Packet switching

this switching technique is used by internet
in packet switching message is broken into individual chunks called packets
each packet will sent individually
each packet will have source ip,destination ip and sequence number

sequence nos will helps to
reorder the packets at destination,deect missing packets,send acks.

i)datagram switching
its also called as connectionless switching
each piece of data is called datagram
datagram contains destination info intermediary devices use this to forwrd the data to right destination

ii)virtual circuit switching

also called as connection oriented switching
in this technique a pre planned route is established before sending data
path is fixed evry packet follow same path