L AIDN

GO ...

TCP/IPTransmission Control Protocol / Internet Protocol...

Communications Protocol

• All communications between devices require that the devices agree on the format of the data. The set of rules defining a format is called a protocol. At the very least, a communications protocol must define the following:

• rate of transmission (in baud or bps)

• whether transmission is to be synchronous or asynchronous

• whether data is to be transmitted in half-duplex or full-duplex mode

• In addition, protocols can include sophisticated techniques for detecting and recovering from transmission errors and for encoding and decoding data.

TCP/IP• The Internet protocol suite is the set

of communications protocols which is used for the Internet and similar networks.

• Generally the most popular protocol stack for wide area networks.

• It is occasionally known as the DoD model due to the foundational influence of the ARPANET.

• TCP/IP provides end-to-end connectivity

• Basically it contain 4 layers.

• Creates a reliable connection between two computers. TCP is one of the main protocols in TCP/IP networks. Whereas the IP protocol deals only with packets, TCP enables two hosts to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent.

Transmission Control Protocol

(TCP)

INTERNET PROTOCOL (IP)

• Provides addressing scheme.. IP specifies the format of packets, also called datagrams, and the addressing scheme. Most networks combine IP with a higher-level protocol called Transmission Control Protocol (TCP), which establishes a virtual connection between a destination and a source.

• IP by itself is something like the postal system. It allows you to address a package and drop it in the system, but there's no direct link between you and the recipient. TCP/IP, on the other hand, establishes a connection between two hosts so that they can send messages back and forth for a period of time.

• The current version of IP is IPv4. A new version, called IPv6 or IPng, is under development.

TCP Header

• Before data is sent, the transmitting host contacts the receiving host to set up a connection-P n known as a virtual circuit. This makes T-Connection-oriented. During the handshake the two hosts agree upon the amount of information to be sent before an acknowledgment is needed (Windowing). TCP takes the large blocks of data from the upper layers and breaks them up into segments that it numbers and sequences. TCP will the pass the segments to the network layer, which will route them through the Internetwork. The receiving TCP can put the segments back into order. After packets are sent, TCP waits for an acknowledgment from the receiving end of the virtual circuit. If no acknowledgment is received then the sending host will retransmit the segment

Main Function of TCP/IP...

TCP accepts data from applications and segments it into a desirable size for transmission between itself and the remote devices. The segment size is determined while TCP is negotiating the connection between the two devices. Either device can dictate the segment size.

TCP maintains timers to identify when packets have taken too long to get to their destination. When an

acknowledgment is not received for a packet and the timer expires, TCP will resend the packet to the destination.

TCP/IP uses sequence numbers to ensure that all packets sent by an application on one device are read in the correct order by an application on another device. The packets might not be received at the transport layer in the correct order, but TCP sequences them in their original order before passing them to the application layer.

Any time two devices are communicating, the possibility exists that one device can send data faster than the other

can accept it. If this happens, the receiving device puts the extra packets into a buffer to be read at the first chance it

gets. When this data overflow persists, however, the buffer is eventually filled and packets begin to drop. TCP performs

some preventive maintenance called flow control to avoid the problem.

Provides acknowledgment times

Segments application layer data stream

Enables sequence number checking

Provides buffer management

Main Function of TCP/IP..TCP uses the concept of the three-way handshake to

initiate a connection between two devices.• A TCP connection begins with a device sending a

request to synchronize sequence numbers (a SYN packet) and initiate a connection.

• The other device receives the message and responds with a SYN message and the sequence number increased by one.

• The first device responds by sending an acknowledgment message (an ACK) to the second device, indicating that the device received the sequence number it expected.

TCP uses a checksum to identify packets that have changed during transport. If a device receives a packet with a bad checksum, it drops the packet and does not send an acknowledgment for the packet. So the sending device will resend the packet. Any time TCP receives a duplicate packet it will drop the duplicate. Any time a TCP device sends data to another device, it

must wait for the acknowledgment that this data was received, To increase the bandwidth utilization, TCP can

change the window size. Whatever the window size is negotiated to be, acknowledgments will only be sent

after that many packets have been received at the receiving device. TCP sets the window size dynamically during a connection, allowing either device involved in the communication to slow down the sending data rate

based on the other devices capacity. This process is known as sliding window because of TCP's ability to

change the window size dynamically.

Initiates connections with 3-way handshake

Performs acknowledgment windowing

Performs error and duplication checking

LayerName

CommonComponents

OSI Reference

Application

HTTP, SMTP, POP3

FTP, DNS

Application

Presentation

Session

Transport TCP, UDP Transport

NetworkIP, ICMP Network

PhysicalEthernet, FDDI

Data Link

Physical

TCP-IP

M

od

el

Working..

APPLICATION LAYER

• This layer makes the Communication B/w Program and Transport protocol.

• Protocols :- HTTP,SMTP,FTP,SNMP,DNS,TELNET

• Application Layer talks to the transport layer through a port . SMTP-25, HTTP-80, FTP-20,21

APPLICATION

TRANSPORT

• The Transport Layer get data from the Application Layer and Divided it into several data packets.

• Both UDP and TCP will get the data from the Application layer and add a HEADER to it when transmitting data. On this header there are several control information, in a particular the source port number.

• UDP header has 8bytes while TCP header has 20 or 24 Bytes.

Working..

NETWORK LAYER

• The network layer is responsible for packet forwarding including routing through intermediate routers, whereas the data link layer is responsible for media access control, flow control and error checking.

• The network layer provides the functional and procedural means of transferring variable length data sequences from a source to a destination host via one or more networks while maintaining the quality of service functions.

Working..

TRANSPORT LAYER

Working..

PHYSICAL LAYER• This layer is define by what type

of Physical Network your computer is connected to. Almost always connected to an Ethernet Network.

• TCP/IP is the set of protocol that deals with layers 3 to 7 from OSI reference model, while Ethernet is a set of protocol that deals with layer 1 and 2 form OSI.

• Ethernet has three Layers

1. Logic Link control (LLC)

2. Media Access Control (MAC)

3. Physical

Logic Link Control (LLC)

•The Logic Link layer (LLC) is in charge of adding information of which protocol on the Internet layer delivered data to be transmitted, so when receiving a frame from the network this layer on the receiving computer has to know to which protocol from the Physical layer it should deliver data. This Layer is Define by IEEE 808.2 Protocol.

Media Access Control (MAC)

• The Media Access Control layer (MAC) is in change of assembling the frame that will be sent over the network.

• This Layer is in charge of adding the source MAC address and the target MAC address – as we explained before.

• MAC address is the physical address of a network Card

• Frames That are targeted to another network will use the router MAC address as the target address.

• This Layer is defined by IEEE 802.3 Protocol, if a cabled network is being used, or by IEEE 802.11 Protocol, if a wireless network is Being Used.

Physical Layer

• The Physical layer is in charge of converting the frame Generated by the MAC layer into electricity (if a cable network is used) or into electromagnetic waves (if a wireless network is being used).

• This layer is also defined by IEEE 802.3 Protocol, If a Cable network is used, or by IEEE 802.11 Protocol, if a Wireless network is used

Full Physical Layer..

Thank you…

Some Universal References..

• http://www.google.com

• http://www.Wikipedia.org

• http://computer.howstuffworks.com/osi1.htm

• http://www.hardwaresecrets.com/article/How-TCP-IP-Protocol-Works-Part-1/433

• http://netcert.tripod.com/ccna/internetworking/dod.html

By :- NIKET.CH & VIKAS PANDEY

E-mail :-

vikaspandey786@hotmail.comniket786@hotmail.com

Website :-

http:/niket786.webs.com

Blog :-

innovtechno.blogspot.com

Slide Share :-

Facebook :-

http://www.fb.com/niket786

http:/www.fb.com/vikaspandey03