SERIAL PORTS AND COMMUNICATION

HELLO FRIENDS
Today i am going to discuss serial  ports and how they communicate or serial communication . i am writing about this technology due to one of
my friend,you want to know why? actually  few days back my friend
went for an interview and he was asked by interviewer that tell
me something about SERIAL AND PARALLEL PORT programming
He got confuse and start stammering .After an interview he gave me call
and start discussing the things. I also became curious after this and start
to search and read about it.

So lets start today's agenda what is serial port and how they communicate.Do not worry i will discuss parallel port in my next blog

SERIAL COMMUNICATION AND SERIAL PORTS:

With a serial connection, information is sent across one wire, one data bit at a time. The 9-pin serial connector on most PCs uses two loops of wire, one in each direction, for data communication, plus additional wires to control the flow of information as you can see in the picture. In any given direction, data is still flowing over a single wire.


now i will give one more picture about pins details

there are only two pins(pin 1 and pin 2) are used for sending and receiving the bits or data.The rest of them are for data flow control.

Now discuss how the serial port communicate or serial communication.IN serial communication only one bit is send at a time.when first bit reach to destination then second start to travel

In serial communication basically there are two fundamental electrical lines one is for clock and other is for data.the actual data is transferred  BIT by BIT on data line.The clock line signals when a bit ends and other bit start.The clock line changes it level,that is when it goes HIGH from low or vice versa  ,signal this for transmission of next bit.

Do serial port need different cable for transmission? yes of course.they are known as serial cable.serial cable has two ends .one end of serial cable know as DTE (data terminal equipment) and other is known as DCE (data circuit-terminating equipment).

so my laptop port is DTE port and the cable connector also know as MALE .I  have give enough example to make the thing clarify.In my upcoming  blogs I  will discuss about parallel port..

SO COFFEE TIME !!

BYE  FOR NOW

DIFFERENCE BETWEEN HASHING AND ENCRYPTION

HELLO friends

When i first read about hashing and encryption i got little bit confused and was thinking "WHAT IS THE DIFFERENCE BETWEEN THEM". Actually I got introduce with these two terms when i was configuring my routers password specially when i was configuring ppp authentication.After that i decide to explore about these two stuffs


let start with brief analysis of both terms and how they are different with each other.

Hashing an encryption both of them are use to hide the original contents of data into some unrecognizable format. so it is clear that both of them  are use to protect the data from intruders.
                                                  

The basic difference is that ENCRYPTION is a reversible process while HASHING is a irreversible process.
Now i will discuss in details regarding algorithm of each one.

    
CASE 1 -HASHING

Basically, this hash algorithm is a formula used to convert a variable-length message into a fixed-length hash. It is also important to understand that this is a one-way function. A message can produce a hash, but a hash cannot produce the original message. After the hash is calculated, it is sent over the network together with the message. At the other end, the receiver performs the same action. It sends the message and the shared key through the hash algorithm and then compares the two hashes to verify whether they match.

    



Now i will tell you what is going on .As you can see that we have a plain text "JOHN" and we have to convert it into cipher text with hashing algorithm. suppose Y is our hashing table algorithm.It always convert plain text "john" into "XYZ" cipher text.Everytime cypher text will be "XYZ".

NOTE-Please pay attention here in third figure that cypher text "XYZ" is not going to convert into "JOHN"
plain text.so it is not easy or intruder to catch private data.

In the above figure(where routers are shown) it is application of hashing algorithm.

CASE 2 -ENCRYPTION.
Now it is time for encryption fundamentals.In encryption also plain text is converted into cypher text and it is reversible process.i will explain with the help of figure below
.
      

refer to above (left) figure ."JOHN" is our plain text and "X" is our encryption algorithm and what we found here every time algorithm"X" will produce different cypher text. As we can see from figure first time cipher text was"XYZ" and second time it is "ABC".so we can conclude that every time it will produce different cipher text unlike HASHING ALGORITHM.

refer to above (right) our cipher text "XYZ" is going to convert into plain text "JOHN" by using encryption algorithm "X".

ENCRYPTION has two class-

1> SYMMETRIC ENCRYPTION-less secure,both peer uses same key yo encrypt and decrypt the data  .      


  2> ASYMMETRIC   ENCRYPTION -more secure ,each peer uses different key to encrypt or decrypt the    

       data                                                             

     

                                               

HOPE THIS DOCUMENT WILL PROVE
USEFUL TO ALL TECH GEEKS.

now i am not anymore confused because i got the concept.








BYE FOR NOW.

DIFFERENT TYPE OF PROTOCOLS

Today i am going to discuss classification of ROUTING PROTOCOLS.
let me discuss different type/class of routing protocols
.
basically routing protocols is divided into two parts-
1> INTERIOR GATEWAY PROTOCOL
2> EXTERIOR GATEWAY PROTOCOL

now INTERIOR GATEWAY PROTOCOL is divided into two parts
1>DISTANCE VECTOR ROUTING PROTOCOLS
2>LINK STATE ROUTING PROTOCOLS

now DISTANCE VECTOR ROUTING PROTOCOLS is divided into 3 parts and i am also giving example of each one

1>CLASSFUL-- RIP and IGRP are example of classful routing protocols where IGRP is cisco proprietary

2>CLASSLESS--RIPV2 and EIGRP are example of classless routing protocols where EIGRP is cisco proprietary

3>1PV6-RIPng and EIGRP for IPV6 are example of IPV6 routong protocols.

now its time for LS routing protocols and again it is classified on same parameters that is classless,ipv6.but in this classification classfull is not present

1>CLASSLESS-OSPFv2 and IS-IS are example of classless routing protocols of link state

2>IPV6--OSPFv3 and IS-IS for IPV6 are example of IPV6 of link state routing protocols..

now its time for EXTERIOR GATEWAY PROTOCOLS PATH VECTOR,again classification on same parameters classful,classless,ipv6.let me give you example to make it more clear.

1>CLASSFUL-- EGP is an example of classful exterior gateway protocols path vector

2>CLASSLESS--BGPv4 is an example of classless exterior gateway protocols path vector

3>1PV6-BGPv4 FOR IPV6 is an example of ip version 6 exterior gateway protocols path vector

i am providing some images of diffrent protocols which will make you help to understand this stuff-