IBM CTI 2572 manual Internet Protocol, IP Address

5.2 Internet Protocol

Internet Protocol (IP) provides a basic packet delivery service. Technically, this service is defined as unreliable, connectionless, and best-effort. Unreliable means that delivery is not guaranteed by the protocol. The packet may be lost, duplicated, delayed, or delivered out of order. Connectionless, as defined previously, means that each packet is treated independently of all others. Finally, best-effortmeans that IP software makes an earnest attempt to deliver packets and does not discard packets capriciously.

IP defines the structure of the unit of data transfer, called an internet datagram. IP also defines the rules and procedures for routing datagrams, how and when error messages should be generated, and the conditions under which a packet will be discarded. The datagram consists of an IP header and the data from the upper layer protocol. Fields in the datagram header contain control information and the IP address of both the source and the destination node.

		IP DATAGRAM
ETHERNET			ETHERNET
HEADER	IP	DATA	TRAILER
	HEADER

IP CONTROL	IP	IP	IP
	SOURCE	DESTINATION		DATA
INFORMATION			OPTIONS
	ADDRESS	ADDRESS

Figure 12 Datagram

IP Address

An IP address is a 32 bit field which uniquely identifies the network and the host computer node. The IP address is conceptually divided into four 8 bit bytes (called octets in some technical publications). An IP address is usually expressed in dotted notation, with one byte expressed as its decimal equivalent. For example, an address containing all 1’s would be notated 255.255.255.255 (see below).

Notation

Binary

Decimal

Byte 1

11111111

255

Byte 2

11111111

255

Byte 3

11111111

255

Byte 4

11111111

255

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CTI 2572 Technical Overview Manual