Protocol

Protocol  means set of rules or language of network. Protocol is communication language of computer or software programming to send and receive bits.  There are different types of protocol like  TCP/IP,  IPX/SPX,  AppleTalk  etc.

TCP/IP

TCP/IP can be use in very large network and it can provide very high security. We cannot access Internet without TCP/IP.  TCP/IP is protocol suite or protocol stack, it is combination of more than 2,600 protocols.  The main protocol in TCP/IP suite are :-

1. TCP(Transmission Control Protocol)     

        It is connection oriented and reliable protocol, it can guarantee the delivery of packets, it use windowing process and it can be use in very large networks.  Windowing means some packets will be send to destination, if acknowledgement will be receive then more packets can be send. TCP can wait for acknowledgement until TTL works.  Time To Live is particular time in seconds for which packet will remain on network. Windowing process use WinSock (Windows Socket) protocol. Maximum size of packet or datagram is 64KB.

2. UDP (User Datagram Protocol)

        It connectionless and non-reliable protocol. It does not guarantee the delivery of packets. It does not use windowing process. It is faster than TCP and can be use in small networks.

3. ICMP (Internet Control Message Protocol)

It works with Ping and Tracert commands. It is use to collect the network information, to check network connection and for network troubleshooting. It can provide messages like Reply, Request time out, Destination host unreachable etc.

4. IGMP (Internet Group Management Protocol)

It can make the group of computers which belongs to same network  and it can make connectivity faster within a group. IGMP is mostly use in multicasting.

5. ARP (Address Resolution Protocol)

It can resolve IP address into MAC address. Data can be deliver only to the physical address and not to the logical address.

NOTE: RARP(Reverse ARP) is use to resolve MAC address into IP address.

6. IP (Internet Protocol)

It is use for logical connection, it is carrier protocol, it is faster and it can also stop broadcasting.

TCP/IP Port

These are logical port. OS use some numbers to identify any protocol or service which are known as Port Number.  Port numbers are assign by IANA (Internet Assigned Numbers Authority). Maximum port numbers are 1 to 65535 and well-known port numbers are 1 to 1024.  For example  :-

HTTP=80,  HTTPS or SSL= 443,  RPC=145,  IMAP=143,  POP=110,  NNTP=119,   SMTP=25,  Telnet=23,  SSH=22,  FTP=21,  DHCP=67,  DNS=53,  LDAP=389,  ICMP=1, Global Catalog=3268,  Kerberos=88,  EIGRP=88,  OSPF=89,  RIP=520   etc.

IP Address

It is logical address or numerical identification of a computer.

It has  IP version 4 and IP version 6.

IP version 4

It is 32 bit address in the decimal format with 4 octets.  It has 2 parts, Network ID and Host ID.

Network ID tell the number of network bits or tell that computer belongs to which network.

Host ID tell the number of hosts per network or tell the unique identification of a computer in particular network.

Subnet Mask is a number which can differentiate between Network ID and Host ID.

It  can  tell  the network bits.   We can use Network Prefix  instead  of  Subnet Mask like     /8   instead of  255.0.0.0

For example :-

Four octets of IP address are  W.X.Y.Z

Minimum value of one octet (All bits are Off):-

0              0              0              0              0              0              0      0      =        0

Maximum value of one octet (All bits are On):-

1              1              1              1              1              1              1      1      =        ?

Every bit has value :-

1              1              1              1              1              1              1      1     

2⁷                          2⁶             2⁵             2⁴             2³             2²             2¹          2⁰

^{128             64               32               16               8                 4                 2        1}            

If we add values of all bits, then 128+64+32+16+8+4+2+1=255

It means IP address value can be 0.0.0.0   to  255.255.255.255

We can use value of binary bits to convert binary into decimal and also to convert decimal into binary.

For eg:     110010

0      0      1      1      0      0      1      0

128  64     32    16    8      4       2      1      =50

For eg:     200

                       

        11001000                   

So,  value of one octet can be 0  to  255

It is divided into different classes.

Class                  Range

                (W  Octet)

  A            1-126

  B            128-191

  C            192-223

  D            224-239

  E            240-254

NOTE: We have to check W octet to identify class of IP address.

        1.228.255.127  -> It is IP address of Class A

        200.1.1.1   -> It is IP address of Class C

NOTE: Subnet Mask will never tell class of IP address but only network ID and host ID

NOTE:

0      is subnet ID or LAN card address

255  is broadcast address

127  is Loopback address and use for network troubleshooting

Class A,B,C (1 to 223) are used for general purpose

Class D (224 to 239 or 224.0.0.0 to 239.255.255.255) reserve for multicasting

Class E (240 to 254) use by NASA for R & D

 

Assuming that we are using default subnet mask :-

(Subnet Mask will not tell class, it will tell network ID and host ID)

       

Types of IP Address

1. Public IP address

They are use to connect Internet directly and has to be register by IANA or APNIC or InterNIC.  Except private IP and special IP,  all are public IP.

2. Private IP address

They are use within private network (LAN and Intranet). They are use to save public IP address, to manage IP addressing etc.

Private IP for class A             ->   10.0.0.1  to    10.255.255.254

      

Private IP for class B             ->   172.16.0.1      to    172.31.255.254

Private IP for class C             ->   192.168.0.1    to    192.168.255.254

3. Special IP address

They are also use within private network but for special purpose only.

(i) Loopback Address -> Any IP address starting with 127.0.0.1

(ii)ICS (Internet Connection Sharing) -> 192.168.0.1  to 192.168.0.254

(iii)APIPA   ->   169.254.0.0   to   169.254.255.254  (or   169.254.0.0)