YEAR 1 CO1 WEEK 23 PROTOCOLS

Is a set of rules to govern communication and data transmission

How to set up a connection How to end a connection How to start a message How to end a message How to deal with corrupted data How to format the data being sent

Error correction -odd /even parity , check sum ,echoing Connection media -Cable /wirless Mode of transmission - Simplex/duplex/serial/parallel Code used for characters -ASCII, UNICODE Bit rate - used for communication

TCP/IP is the network protocol used on the the internet

Transmission Control Protocol

Group of protocols organised by a function Many models Eg TCP = 4 layers

• We can focus on one layer at a time • when u develop software and hardware as you can focus on one small part instead of everything else • we can test it separately • we can recognise it by what layer does what

HTTP- web pages, FTP- FILE TRANSFER PROTOCOL ,SMTP- sending to a server ,POP- moves a message so can’t be seen everywhere , IMAP- copies message so can be seen everywhere

Layer 4 - Application Layer3 - Transport Layer 2 - Internet/ IP layer Layer 1 - Network or Datalink

• Deals with the data • Provides access to email and files and websites across ip network Layer where communication process begins. Interacts directly with software application such as Web browsers and email clients. Prepares data for transmission by converting into format that can be sent + received over the network.

• Splits data into packets and number sequentially • Adds port number to be used • error checking • Connection-less mode transmitter just send packets with out setting up session Receives data from application layer. Responsible for end-to-end communication between source and destination. Breaks data into smaller equal parts called packets. Each assigned numbers so can be reassembled in the correct order.

• Sorts out how data gets from one place to another • sorts out ip Receives packets from transport layer. Adds header to each packet containing senders IP address + recievers IP address. Responsible for routing each packet across network using the IP addresses in the headers.

Receives packets from Internet Layer and prepares for transmission over physical network. Translates digital packets into electrical, optical or wireless signal. On receiving end translated back to digital packets.

Physical protocols is set of rules for hardware Logical is set of rules for software