1. NETWORKING CONCEPTS

2. TCP/IP The TCPIIP protocol suite was developed prior to the OSI model TCP/IP protocol suite was defined as having four layers: Host-to-network, Internet Transport Application

3. TCP/IP

4. the OSI model specifies which functions belong to each of its layers, the layers of the TCP/IP protocol suite contain relatively independent protocols At the transport layer, TCP/IP defines three protocols: Transmission Control Protocol (TCP), User Datagram Protocol (UDP), Stream Control Transmission Protocol (SCTP). At the network layer, the main protocol defined by TCP/IP is the Internetworking Protocol (IP)

5. TCP/IP Network Layer Job is to permit host to inject packets into any n/w & have them to travel independently to the destination They may arrive in a different order than sent and higher layers rearrange it if order delivery is required At the network, TCP/IP supports the Internetworking Protocol. IP four supporting protocols: ARP,RARP, ICMP, and IGMP

6. NETWORK LAYER Internetworking Protocol (IP) It is an unreliable and connectionless protocol no error checking or tracking IP does its best to get a transmission through to its destination, but with no guarantees. IP transports data in packets called datagrams, each of which is transported separately Datagrams can travel along different routes and can arrive out of sequence or be duplicated.

7. NETWORK LAYER Internetworking Protocol (IP) IP does not keep track of the routes no facility for reordering datagrams once they arrive at their destination. Address Resolution Protocol(ARP) used to associate a logical address with a physical address On LAN, each device on a link is identified by a physical or station address, usually imprinted on the network interface card (NIC). ARP is used to find the physical address of the node when its Internet address is known

8. NETWORK LAYER Reverse Address Resolution Protocol(RARP) allows a host to discover its Internet address when it knows only its physical address Internet Control Message Protocol(ICMP) mechanism used by hosts and gateways to send notification of datagram problems back to the sender Internet Group Message Protocol(IGMP) used to facilitate the simultaneous transmission of a message to a group of recipients

9. TRANSPORT LAYER transport layer was represented in TCP/IP by two protocols: TCP and UDP TCP and UDP are responsible for delivery of a message from a process (running program) to another process UDP Unreliable connectionless protocol that do not want sequencing or flow control TCP Reliable connection oriented protocol that allows a stream on one machine to be delivered without error

10. TRANSPORT LAYER TCP At the sending end of each transmission, TCP divides a stream of data into smaller units called segments Each segment includes a sequence number for reordering after receipt, together with an acknowledgment number for the segments received Segments are carried across the internet inside of IP datagrams On receiving end, TCP collects each datagram as it comes in and reorders the transmission based on sequence numbers

11. APPLICATION LAYER Equivalent to the combined session, presentation, and application layers in the OSI Contain all high level protocol like TELNET,FTP TELNET allows user on one machine to log on to distant machine and work there FTP for way to move data from one machine to other