Internet Protocol Suite




Internet Protocol Suite

Ø  The Internet protocol suite is the set of communication protocols used for the internet and similar networks, and generally the most popular protocol stack for wide area networks.
Ø  It is commonly known as TCP/IP.
Ø  It is occasionally known as the DoD model due to the foundational influence of the ARPANET.
Ø  TCP/IP provides end-to-end connectivity specifying how data should be formatted, addressed , transmitted , routed and received at the destination.
Ø  It has 4 abstraction layer:
-          Link Layer : contains communication technologies for a local network.
-          The internet layer connectes local networks, thus establishing internetworking
-          The transport layer handles host-to-host communication
-          The application layer contains all protocols for specific data communications services on a process-to-process level. Example HTTP specifies the web browser communication with a web server.

TCP (Transmission Control Protocol)

Ø  TCP is one of the core protocols of the internet protocol suite.
Ø  TCP provides reliable , ordered delivery of a stream of octets from a program on one computer to another program on another computer.
Ø  TCP contains major internet application such as THE WWW, email, remote administration and file transfer.
Ø  TCP provides a communication service at an intermediate level between an application program and the IP.
Ø  When an application program desires to send a large bundle of data across the internet using IP, instead of breaking the data into IP-sized pieces and issuing a series of requests, the software can issues a single requests to TCP.
Ø  TCP has reliability (error recovery) this is made possible by using sequence and acknowledgment numbers (bytes) in the TCP header field.
Ø  TCP can control flow of data , this uses the window field which determines the maximum amount at a given time.

TCP Segments Structure:

Ø  TCP accepts data from a data stream, segments it into chunks and adds a TCP header creating TCP segments.
Ø  The TCP segments encapsulated into an internet IP datagram.
Ø  The TCP segments consists of a segment header and data section.
Ø  The TCP header contains 10 mandatory fields , and an optional extension field (Options).









·         Data offset (4-bits): Specifies the size of the TCP header in 32 bit words.
·         Reserved (3-bits): For future use
·         Flags (9-bits) (aka Control bits): contains 9 1-bit flags
-          NS (1-bit): ECN-nonce concealment protection (RFC 3540)
-          CWR (1 bit): Congestion Window Reduced (CWR) flag is set by sending host to indicate that it received a TCP segment with the ECE flag set ( RFC 3168)
-          ECE (1-bit): ECP-Echo indicates
-          URG (1-bit): indicates that the urgent pointer field is significant
-          ACK (1-bit): indicates acknowledgment field is significant.
-          PSH (1-bit): Push function, Asks to push the buffered data to the receiving application.
-          RST(1-bit): Reset the connection
-          SYN (1-bit): Synchronize sequence Numbers.
-          FIN (1-bit)-No more data from sender.







TCP PORTS:

Ø  TCP uses port numbers to identify sending and receiving application end-points on a host or internet sockets.
Ø  Each side of a TCP connection has an associated 16-bit unsigned port number (0-65535) reserved by the sending or receiving application.
Ø  Arriving TCP data packets are identified as belonging to a specific TCP connection by its sockets.
Ø  TCP sockets is the combination of Source host address, source port , destination host address with his port.
Ø  Port numbers are categorized into three basic categories: well-known, registered and dynamic/private.




:: USER DATAGRAM PROTOCOL::

Ø  Member of Internet Protocol Suite, and the set of network protocol used for the internet.
Ø  With UDP, computer applications can send message (datagrams) to other hosts on an internet protocol network without prior communications to set up special transmission channels or data paths.
Ø  Attributes:
-          Transaction-oriented
-          Provides Datagrams
-          Stateless (suitable for very large number of client)
-          Lack of retransmission delays
-          Unidirectional communication

What is DATAGRAM?

Ø  A datagram is a basic transfer unit associated with a packet-switched network in which the delivery , arrival time, and order of arrival are not guaranteed by the network service.
Ø  In datagram, user only provides the destination address.
Ø  Datagram service routes datagram without first creating a predetermined path, many datagram in the same group can travel along different paths before reaching the same destination.

Structure of Datagram:

Ø  Each datagram has two components , a header and a data payload.
Ø  The header contains all the info sufficient for routing from the originating equipment to the destination without relying on prior exchanges between the equipment and the network.
Ø  Headers may include source and destination address as well as a type field.
Ø  The payload is the data to be transported.

UDP service Ports::::  
Ø  UDP applications use datagram sockets to establish host-to-host communications.
Ø  An application binds a socket to its endpoint of data transmission, which is a combination of an IP address and a service port.
Ø  UDP provides application multiplexing (via port numbers) and integrity verification (via checksum) of the header and payload.




Length:
-          A field that specifies the length in bytes of the entire datagram: header and data.
The minimum length is 8 byte since that’s the length of the header.

By Er.AJAI SINGH on Saturday, 19 January 2013 | , | A comment?
0 responses to “Internet Protocol Suite”

Leave a Reply