Protocols

Protocols

 Protocol is a language which is used to communicate with two machines or to transfer data within a network.  Systems typically do not use single protocol to transmision files, they use family of protocols as IPX/SPX, Net Bios, TCP/IP and many other protocol suites.  

·        IPX/SPX- IPX/SPX stands for Internetwork Packet Exchange/ Sequenced Packet Exchange. Novell is largely responsible for the use of IPX as a popular computer networking protocol. IPX is a network layer protocol (layer 3 of the OSI Model), while SPX is a transport layer protocol (layer 4 of the OSI Model). IPX/SPX both provide connection similar to TCP/IP protocol.

·        Net Bios- It stands for Network Basic Input/Output System. It provides services similar to session layer of OSI Model to by allowing computers to communicate over a LAN.

      NetBIOS provides three distinct services:

• Name service (NetBIOS-NS) for name registration and resolution.
• Datagram distribution service (NetBIOS-DGM) for connectionless communication.
• Session service (NetBIOS-SSN) for connection-oriented communication.

·        Newlink  IPX/SPX- It is Microsoft’s implementation of Novell’s IPX/SPX protocols. It packagess data to be compatible with client/server services on network.The main function of it is to act as a transport protocol to route packets through internetworks.

·        TCP/IP- It is a reliable connection oriented protocol on the transport layer which provides internetwork delivery of data and to implement data flow.

        Internet Protocol is the building block of internet. IP is a connectionless protocol. It relies on other layers to  provide error detection and correction. Sometimes IP refers to unreliable protocol because it contains no error detection or recovery code.

Protocols under TCP/IP Protocols:-

·        FTP- File Transfer Protocol used for exchanging files over the internet. FTP is most commonly used to download a file from a server using internet or upload a file to a server.

Port Numbers: 20dataport), 21(control port)

·        SMTP- Simple Mail Transfer Protocols for sending e-mail messages between servers. Basically, it is used to send messages from a mail client to mail server.

·        POP3- Post Office Protocol is used to retrieve e-mail from mail server.

·        HTTP- Hypertext Transfer Protocol is a underlying protocol used by the World Wide Web. It defines how messages formatted and transmitted. For example, when we enter a URL in browser, it actually sends an HTTP command to the web server directing it to fetch and transmitted the requested page. Port Number: 80.

·        ICMP- Internet Control Message Protocol is used to send error and control messages in a network

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·        ARP- Address Resolution Protocol is used to map the known  IP Address into physical address.

·        RARP- Reverse Address Resolution Protocol is used to map physical IP Address to IP Address.

·        DHCP-dynamic Host Control Protocol is used for assigning dynamic IP Addresses to devices on a network. With this, a device can have a different IP address every time it connects to the network.

·        DNS- Domain Name system is an Internet service that translates domain names into IP addresses because domain names are alphabetic and they are easy to remember. For example, the domain name www.example.com might translate to 192.105.232.4