IP Fundamentals

IP Fundamental:-

An IP address is a numeric identifier assigned to each machine on an IP network. It designates the specific location of a device on the network. (Internet Protocol) is the primary network protocol used on the Internet, developed in the 1970s. On the Internet and many other networks, IP is often used together with the Transport Control Protocol (TCP) and referred to interchangeably as TCP/IP.

An IP address is a software address, not a hardware address –the latter is hard coded on a network interface card (NIC) and used for finding hosts on a local network. Data on an Internet Protocol network is organized into packets. Each IP packet includes both a header (that specifies source, destination, and other information about the data) and the message data itself.IP functions at layer 3 of the OSI model.

Public IP addresses

A public IP address is any valid address, or number, that can be accessed over the Internet.  Internet standards groups, such as the Network Information Center (NIC) or the Internet Assigned Numbers Authority (IANA), are the organizations responsible for registering IP ranges and assigning them to organizations, such as Internet Service Providers (ISPs).In the Cloud (n) system, a public IP address is an identifier assigned to a virtual router on the network. Any resources that will be available over the Internet will require a public IP address.  Public IP addresses can be added in the Cloud Console.

Private IP addresses

A private IP address is any number or address assigned to a device on a private TCP/IP Local Area Network that is accessible only within the Local Area Network.  For a resource inside the Local Area Network to be accessible over the Internet, a device within the Local Area Network must be connected to the Internet with a public IP address, and the networking must be appropriately configured.  The same Internet standards organizations have reserved the following three IP address ranges that will never be registered publicly.

IP Addressing Scheme:-

An IP address consists of 32 bits of information. These bits are divided into four sections, referred to as octets or bytes, each containing 1 bytes (8 bits). We can depict an IP address using one of three methods:-

• Dotted-decimal, as in 172.16.30.56
• Binary, as in 10101100.00010000.00011110.00111000
• Hexadecimal, as in AC.10.1E.38

Classes of IP addresses:-

• Class A Addresses :- Range 0 to 127 Format :-  node.node.node

• Class B Addresses :- Range 128 to 191 Format :-  Network.node.node

• Class C Addresses :- Range 192 to 223 Format :-  Network.Network.node

• Class D Addresses :- Range 224 to 239, used for multicast addresses

• Class E Addresses :- Range 240 to 255, used for scientific purposes

IP Frame format:-

The IP packet format consists of these fields:-

• Version field(4 bits) indicates the version of IP currently used.
• • IP Header Length (IHL) field(4 bits) indicates how many 32-bit words are in the IP header.
  • Type-of-service field(8 bits) specifies how a particular upper-layer protocol would like the current datagram to be handled. Datagrams can be assigned various levels of importance through this field.
  • Total Length field(16 bits) specifies the length of the entire IP packet, including data and header, in bytes.
  • Identification field(16 bits) contains an integer that identifies the current datagram. This field is used to help reconstruct datagram fragments.
  • Flags field(4 bits; one is not used) controls whether routers are allowed to fragment a packet and indicates the parts of a packet to the receiver.
  • Time-to-live field(8 bits) maintains a counter that gradually decrements to zero, at which point the datagram is discarded. This keeps packets from looping endlessly.
  • Protocol field(8 bits) indicates which upper-layer protocol receives incoming packets after IP processing is complete.
  • Header Checksum field(16 bits) helps ensure IP header integrity.
  • Source Address field(32 bits) specifies the sending node.
  • Destination Address field(32 bits) specifies the receiving node.
  • Options field(32 bits) allows IP to support various options, such as security.
  • Data field(32 bits) contains upper-layer information.