network minutes/a network protokol are an accurate agreement, after the data between computers and/or. Processes to be exchanged, which are connected by a net (distributed system). The agreement consists of a sentence of rules and formats (syntax),the communication behavior of the communicating instances in the computers determine (semantics).
The exchange of messages requires frequently an interaction of different minutes, which take over different tasks (for example Internet minutes family). In order to be able, become to control the associated complexity thoseindividual minutes in layers organizes. In the framework each minutes of a certain layer belong to such an architecture and are responsible for the completion of the special tasks (for example examining the data for completeness - layer 2). Minutes of higher layers use servicesof minutes of deeper layers (layer 3 z relies. B. on the fact that the data arrived complete). Together in such a way structured minutes form a minutes pile - following the ISO OSI reference model (see also DoD Schichtenmodell). Realign a certain layer becomealso as log data units (protocol DATA units) designates. Under the generic term TCP/IP are approximately 500 (!) Minutes in summary. TCP/IP stands generally for linguistic usage for minutes with data exchange between different computers.
Table of contents
work on] the typical structure
of minutes the structure of a packet described in minutes for data exchangeInformation about the package as for example:
- its senders and receiver
- the type of the package (z. B. Connection establishment, connection clearing or pure utilizable data)
- the package length
- a check total
these information are placed in front the utilizable data as header so mentioned or attached as Trailer.
In additionbecome firm in some minutes package sequences for the connection establishment and - dismantling described. These measures cause - the so-called for further data traffic (Traffic) on the data lines. Overhead. This Overhead is, because it loads the capacity, becomes unwanted however due to the importantTasks, which carry minutes out, usually taken in purchase. With User Datagram Protocol (UDP) also minutes with only minimum Overhead are available in the transport layer, which does not ensure an end final inspection of the transmission.
distinguishers of network protokols
- Number of parties, which participate in communication: There is a receiver for a transmission in each case, one speaks of Unicast, with transmissions to several participants of multicast.
- If communication takes place only in a direction, speaksone of simplex, flows the data alternately into both directions, from half duplex or at the same time into both directions, from full-duplex.
- Position of the communication participants: If these are among themselves equal, one speaks of Peer ton Peer or more symmetrically otherwise of asymmetrical communication. Tofurthest common asymmetrical model is the Client server system, with which a service tenderer ( the server) inquiries of different Clients worked on (whereby there is always the Clients, which initiates communication, D. h. a channel open).
- Becomes after an inquiry up Waited , one speaks answer of synchronous communication, otherwise of asynchronous communication.
- During package-oriented communication messages become and/or. Packets transferred, with the Streaming with a continuous data stream of individual indications at
- connectingoriented ( connection oriented) minutes becomes worked by specialPackage sequences the beginning and the end of a connection defines. Within such a connection by minutes it is mostly ensured that packages in a certain order to arrive and/or guaranteed that the packages are again sent, if they did not arrive (e.g.TCP). Connecting lots (connectionless) of minutes do not offer this comfort, have however a smaller Overhead. (e.g. UDP, RTP)
the substantial tasks of modern, high performance minutes
- a safe and reliable connection establishment between the computers taken part in communication(Handshake)
- reliable setting of packages
- repeating not arrived packages
- setting the packets to/the desired receivers
- guaranteeing an error free transmission (check total)
- joining arriving packets in the correct order
- preventing an interference unauthorized third (by coding)
Anhand des Verbindungsaufbau-Prozederes des TCP-Protokolls soll ein einfaches praktisches Beispiel gezeigt werden. (see also to handshake - procedures)
- first computer 1 sends a package, in which it is located that he would like to develop a connection to computer 2.
- Whereupon computer answers2 that it is ready for it.
- Computer 1 confirms afterwards computer 2 that it understood that computer is ready 2.
The connection is manufactured thereby, and which actual data exchange can begin.
use of minutes
the most well-knownUse of minutes takes place approximately around Internet, here provides it for (application - (minutes designation)):
The functions of minutes construct partially one on the other. Thus for example minutes TCP and IP solve the problem of the data communication. Minutes smtp necessarily for conveying enamels again the function to dispatch data and touch down in additionthe TCP up.
in the year 1968 on Veranlassung of the American Department of Defense (DoD) attempts were accomplished, won with those fundamental realizations over the function mode by computer networkswill should. As practical result 1969 ARPANET - the project were presented. Here for the communication administration additional computers were furnished with clients the net. ARPANET was presented 1972 in the public and continued to develop constantly in the subsequent years. Upthe nodes was used UNIX 6. Starting from 1983 TCP/IP minutes had become generally accepted. From the ARPANET for military interests a separate net was divided, the MILNET. With TCP/IP a standard of reliable and efficient data communication was established. The massivecommercial utilization began.
- Hein/Reisner (2001): TCP/IP packed. Bonn: Mitp publishing house
- victory mouth, G. (2003): Technology of the nets. 5. Aufl., 1296 S., Berlin and open brook: VDE publishing house
- king, H. (2003): Protocol engineering - principle, description and development of communication protocols.B.G. Teubner Stuttgart Leipzig Wiesbaden
Web on the left of
- http://www.easy-network.de/protokolle - minutes under Windows install
- http://www.iana.org/assignments/protocol-numbers - IANA list of minutes with the pertinent numbers
A listing of usual minutes and their description in the Wikipedia can in the category network minutes are found.