What is a Protocol .Explain IP and TCP ?

Protocol  :  A  protocol  is  a  set of  rules  which govern  how computers  can   communicate.  (or) A   protocol  is  a   set  of  rules   to  communicate  client  is  server.

Protocol  dictates  the   way  that  addresses  are  assigned  to  machines,  formats  in   which  can be  sent  in  one   go.

The   whole  of  the  Internet   is  under  pinned   by  just  two Protocols. 1) Internet   protocol  (IP) 2) Transmission   control   protocol  (TCP)

The  world  wide web  address  a  couple  more into   the internet 1)    HTTP  (Hypertext  transfer  protocol) 2)    Common  gateway  Interface  (CGI)

Ip  and  TCP:

The  two  protocols  upon  which  the  whole  Internet   runs  are  Internet  protocol  and  Transmission  control  protocol.

These  protocols  provide  all  of  the  requirements  to  transmit   is   receive  data  across   complex  WANS.

Networks   are made  of  layers    with  each   layer  providing  a  different  type  of  functionality.

Internet   protocol: In   the Internet  layer  of  a  sending  machine   the  data  is  split   in  to  packets  which  also  contain  addressing   information   about  the   recipient. Implementations   at  the  Internet  protocol  are   Probably  the  most  common    way  to  generating  is   addressing    data  packets. If   packets  have   b/w  20  and  60 bytes  of  header   information  and  up  to  65,515  bytes  of  data. The  structure   of  header, which  contains  all  of  the  information  that  might  be  needed  to  get  a  packet   from  point  A   to  point  B. IP packet header

I.P was designed to be used in military networks which had the ability to survive catastrophic failures of some nodes.

If  you built a network in which all data passed through a single point in , for instance , one point was terminally damaged in some way then your whole network would be rendered useless.

IP doesn’t work like that.

If some node was destroyed , data would simply find a way to its destination.

IP as relatively limited functionality.

The protocol makes no Guatantee of delivery.

Just bacause a packet of data is sent , there is no reason to except that it will arrive.

Large messages , which means any over 65,515 bytes , must be sent as a series of packets.

Because these packets may be sent along different routes they can arrive in a different order from that in which they were sent.

TCP( Transmission control protocol )

If several packets were sent , TCP must store them as they arrive until the whole data set is stored.

IP gets the data on to and off the network but on its own it provides no support for all applications.

The data packets are not sequenced.

TCP fills in some of the gaps left by IP.

A packet sent from a system which was TCP has another set of headers in addition to the IP-address.

These provide control information for use by TCP. The TCP header

When a host receives a data packet the IP code removes the IP header & passed the packet on to TCP code.

If only one packet was sent the TCP headers are removed and the packet is passed on to the application.

As each packet is stored, TCP sends an acknowledgement message back to the sending message back to the sending machine indicating which packet it now has.

If can acknowledgement is not received by the server for a specific packet it will transmit that packet once more.

Large volumes of data can be sent & their safe arrival is guaranteed.

Internet Addresses: Networking only happens if machines can identify each other and so send data to the correct plane. All machines connected to the internet and using IP have a unique address.

Some machines such as those on organizational Can’s have fixed address.

The addresses are written in the form 192.168.0.1

Each of the four bytes in the addressed is represented by an integer in the range 0 to 255.

Server runs a number of Internet connected applications at the same time.

Each application is assigned a port number.

Port number is a unique address of an application given by local o/s.