Thursday, August 13, 2009

What is Protocol ?

In Information technology, a protocol is the special set of rules OR an agreed-upon format for transmitting data between two devices. The protocol determines the following:
  • The type of error checking to be used
  • Data compression method, if anyhow the sending device will indicate that it has finished sending a message
  • How the receiving device will indicate that it has received a message

WHAT IS TCP/IP PROTOCOL ?

The TCP/IP suite of protocols is the set of protocols used to communicate across the Internet. It is also widely used on many organizational networks due to its flexibility and wide array of functionality provided. Microsoft who had originally developed their own set of protocols now is more widely using TCP/IP, at first for transport and now to support other services.





TCP/IP LAYERS

Layer 7: Application Layer

Defines interface to user processes for communication and data transfer in network
• Provides standardized services such as virtual terminal, file and job transfer and operations

Layer 6: Presentation Layer
• Masks the differences of data formats between dissimilar systems
• Specifies architecture-independent data transfer format
• Encodes and decodes data; encrypts and decrypts data; compresses and decompresses data

Layer 5: Session Layer
• Manages user sessions and dialogues
• Controls establishment and termination of logic links between users
• Reports upper layer errors

Layer 4: Transport Layer
• Manages end-to-end message delivery in network
• Provides reliable and sequential packet delivery through error recovery and flow control mechanisms
• Provides connectionless oriented packet delivery

Layer 3: Network Layer
• Determines how data are transferred between network devices
• Routes packets according to unique network device addresses
• Provides flow and congestion control to prevent network resource depletion

Layer 2: Data Link Layer
• Defines procedures for operating the communication links
• Frames packets
• Detects and corrects packets transmit errors

Layer 1: Physical Layer
• Defines physical means of sending data over network devices
• Interfaces between network medium and devices
• Defines optical, electrical and mechanical characteristics



TCP/IP By Layer

Link Layer

  • SLIP PROTOCOL - Serial Line Internet Protocol. This protocol places data packets into data frames in preparation for transport across network hardware media. This protocol is used for sending data across serial lines. There is no error correction, addressing or packet identification. There is no authentication or negotiation capabilities with SLIP. SLIP will only support transport of IP packets.
  • CSLIP PROTOCOL - Compressed SLIP is essentially data compression of the SLIP protocol. It uses Van Jacobson compression to drastically reduce the overhead of packet overhead. This may also be used with PPP and called CPPP.
  • PPP PROTOCOL- Point to Point Protocol is a form of serial line data encapsulation that is an improvement over SLIP which provides serial bi-directional communication. It is much like SLIP but can support AppleTalk, IPX, TCP/IP, and NetBEUI along with TCP/IP which is supported by SLIP. It can negociate connection parameters such as speed along with the ability to support PAP and CHAP user authentication.
  • Ethernet - Ethernet is not really called a protocol. There are also many types of ethernet. The most common ethernet which is used to control the handling of data at the lowest layer of the network model is 802.3 ethernet. 802.3 ethernet privides a means of encapsulating data frames to be sent between computers. It specifies how network data collisions are handled along with hardware addressing of networkcards.

    Network Layer
  • ARP PROTOCOL- Address Resolution Protocol enables the packaging of IP data into Ethernet packages. It is the system and messaging protocol that is used to find the Ethernet (hardware) address from a specific IP number. Without this protocol, the Ethernet package could not be generated from the IP package, because the Ethernet address could not be determined.
  • IP PROTOCOL- Internet Protocol. Except for ARP and RARP all protocols' data packets will be packaged into an IP data packet. IP provides the mechanism to use software to address and manage data packets being sent to computers.
  • RARP PROTOCOL- Reverse address resolution protocol is used to allow a computer without a local permanent data storage media to determine its IP address from its Ethernet address.

    Transport Layer
  • TCP PROTOCOL- A reliable connection oriented protocol used to control the management of application level services between computers. It is used for transport by some applications.
  • UDP PROTOCOL- An unreliable connection less protocol used to control the management of application level services between computers. It is used for transport by some applications which must provide their own reliability.
  • ICMP PROTOCOL- Internet control message protocol (ICMP) provides management and error reporting to help manage the process of sending data between computers. (Management). This protocol is used to report connection status back to computers that are trying to connect other computers. For example, it may report that a destination host is not reachable.
  • IGMP PROTOCOL- Internet Group Management Protocol used to support multicasting. IGMP messages are used by multicast routers to track group memberships on each of its networks.
Application Layer
  • FTP PROTOCOL- File Transfer Protocol allows file transfer between two computers with login required.
  • TFTP PROTOCOL- Trivial File Transfer Protocol allows file transfer between two computers with no login required. It is limited, and is intended for diskless stations.
  • NFS PROTOCOL- Network File System is a protocol that allows UNIX and Linux systems remotely mount each other's file systems.
  • SNMP PROTOCOL- Simple Network Management Protocol is used to manage all types of network elements based on various data sent and received.
  • SMTP PROTOCOL- Simple Mail Transfer Protocol is used to transport mail. Simple Mail Transport Protocol is used on the internet, it is not a transport layer protocol but is an application layer protocol.
  • HTTP PROTOCOL- Hypertext Transfer Protocol is used to transport HTML pages from web servers to web browsers. The protocol used to communicate between web servers and web browser software clients.
  • BOOTP PROTOCOL- Bootstrap protocol is used to assign an IP address to diskless computers and tell it what server and file to load which will provide it with an operating system.
  • DHCP PROTOCOL- Dynamic host configuration protocol is a method of assigning and controlling the IP addresses of computers on a given network. It is a server based service that automatically assigns IP numbers when a computer boots. This way the IP address of a computer does not need to be assigned manually. This makes changing networks easier to manage. DHCP can perform all the functions of BOOTP.
  • BGP PROTOCOL- Border Gateway Protocol. When two systems are using BGP, they establish a TCP connection, then send each other their BGP routing tables. BGP uses distance vectoring. It detects failures by sending periodic keep alive messages to its neighbors every 30 seconds. It exchanges information about reachable networks with other BGP systems including the full path of systems that are between them. Described by RFC 1267, 1268, and 1497.
  • EGP PROTOCOL- Exterior Gateway Protocol is used between routers of different systems.
  • IGP PROTOCOL- Interior Gateway Protocol. The name used to describe the fact that each system on the internet can choose its own routing protocol. RIP and OSPF are interior gateway protocols.
  • RIP PROTOCOL- Routing Information Protocol is used to dynamically update router tables on WANs or the internet. A distance-vector algorithm is used to calculate the best route for a packet. RFC 1058, 1388 (RIP2).
  • OSPF PROTOCOL- Open Shortest Path First dynamic routing protocol. A link state protocol rather than a distance vector protocol. It tests the status of its link to each of its neighbors and sends the acquired information to them.
  • POP3 PROTOCOL- Post Office Protocol version 3 is used by clients to access an internet mail server to get mail. It is not a transport layer protocol.
  • IMAP4 PROTOCOL- Internet Mail Access Protocol version 4 is the replacement for POP3.
  • Telnet is used to remotely open a session on another computer. It relies on TCP for transport and is defined by RFC854.

Bandwidth Control
  • BAP PROTOCOL- Bandwidth Allocation Protocol is a bandwidth control protocol for PPP connections. It works with BACP.
  • BACP PROTOCOL- Bandwidth Allocation Control Protocol.


TCP/IP by Function

Packaging and Low Level

  • IP PROTOCOL- Internet Protocol. Except for ARP and RARP all protocols' data packets will be packaged into an IP data packet. IP provides the mechanism to use software to address and manage data packets being sent to computers.
  • SLIP PROTOCOL- Serial Line Internet Protocol. This protocol places data packets into data frames in preparation for transport across network hardware media. This protocol is used for sending data across serial lines. There is no error correction, addressing or packet identification. There is no authentication or negotiation capabilities with SLIP. SLIP will only support transport of IP packets.
  • CSLIP PROTOCOL- Compressed SLIP is essentially data compression of the SLIP protocol. It uses Van Jacobson compression to drastically reduce the overhead of packet overhead. This may also be used with PPP and called CPPP.
  • PPP PROTOCOL- Point to Point Protocol is a form of serial line data encapsulation that is an improvement over SLIP which provides serial bi-directional communication. It is much like SLIP but can support AppleTalk, IPX, TCP/IP, and NetBEUI along with TCP/IP which is supported by SLIP. It can negociate connection parameters such as speed along with the ability to support PAP and CHAP user authentication.
  • Ethernet - Ethernet is not really called a protocol. There are also many types of ethernet. The most common ethernet which is used to control the handling of data at the lowest layer of the network model is 802.3 ethernet. 802.3 ethernet privides a means of encapsulating data frames to be sent between computers. It specifies how network data collisions are handled along with hardware addressing of network cards.

Transport and Basic Functions
  • TCP PROTOCOL- A reliable connection oriented protocol used to control the management of application level services between computers. It is used for transport by some applications.
  • UDP PROTOCOL- An unreliable connection less protocol used to control the management of application level services between computers. It is used for transport by some applications which must provide their own reliability.


Network Management

  • SNMP PROTOCOL- Simple Network Management Protocol is used to manage all types of network elements based on various data sent and received.
  • ICMP PROTOCOL- Internet control message protocol provides management and error reporting to help manage the process of sending data between computers. (Management). This protocol is used to report connection status back to computers that are trying to connect other computers. For example, it may report that a destination host is not reachable. This protocol is required for basic TCP/IP operations.
  • ARP PROTOCOL- Address Resolution Protocol enables the packaging of IP data into ethernet packages. It is the system and messaging protocol that is used to find the ethernet (hardware) address from a specific IP number. Without this protocol, the ethernet package could not be generated from the IP package, because the ethernet address could not be determined. protocol is used to report connection status back to computers that are trying to connect other computers. For example, it may report that a destination host is not reachable. This protocol is required for basic TCP/IP operations.

Host Management
  • BOOTP PROTOCOL- Bootstrap protocol is used to assign an IP address to diskless computers and tell it what server and file to load which will provide it with an operating system.
  • DHCP PROTOCOL- Dynamic host configuration protocol is a method of assigning and controlling the IP addresses of computers on a given network. It is a server based service that automatically assigns IP numbers when a computer boots. This way the IP address of a computer does not need to be assigned manually. This makes changing networks easier to manage. DHCP can perform all the functions of BOOTP.
  • RARP PROTOCOL- Reverse address resolution protocol is used to allow a computer without a local permanent data storage media to determine its IP address from its ethernet address.
Mail Protocols
  • SMTP PROTOCOL- Simple Mail Transfer Protocol is used to transport mail. Simple Mail Transport Protocol is used on the internet, it is not a transport layer protocol but is an application layer protocol.
  • POP3 PROTOCOL- Post Office Protocol version 3 is used by clients to access an internet mail server to get mail. It is not a transport layer protocol.
  • IMAP4 PROTOCOL- Internet Mail Access Protocol version 4 is the replacement for POP3.

Multicasting Protocols
  • IGMP PROTOCOL- Internet Group Management Protocol used to support multicasting. IGMP messages are used by multicast routers to track group memberships on each of its networks.

Routing Protocols
  • BGP PROTOCOL- Border Gateway Protocol. When two systems are using BGP, they establish a TCP connection, then send each other their BGP routing tables. BGP uses distance vectoring. It detects failures by sending periodic keep alive messages to its neighbors every 30 seconds. It exchanges information about reachable networks with other BGP systems including the full path of systems that are between them. Described by RFC 1267, 1268, and 1497
  • EGP PROTOCOL- Exterior Gateway Protocol is used between routers of different systems.
  • IGP PROTOCOL- Interior Gateway Protocol. The name used to describe the fact that each system on the internet can choose its own routing protocol. RIP and OSPF are interior gateway protocols.
  • RIP PROTOCOL- Routing Information Protocol is used to dynamically update router tables on WANs or the Internet.
  • OSPF PROTOCOL - Open Shortest Path First dynamic routing protocol. A link state protocol rather than a distance vector protocol. It tests the status of its link to each of its neighbors and sends the acquired information to them.




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