One large network of communication technology would be difficult to implement. As a result, we split up various components of the network into smaller modules or layers. The standard model of a network is the Open Systems Interconnection (OSI) model set by the International Organization Standard (ISO).
Other network models exist, though they are all split into similar layers. Each layer uses the services that the layer below provides, while providing services for the layer above it. Each layer can only communicate with the same layer on the destination device.
OSI (Open Systems Interconnection) is a 7-layer network model specified by ISO (International Organization for Standardization) norm and is widely used all around the world. The concept of a seven-layer model was provided by the work of Charles Bachman, Honeywell information Services. Various aspects of OSI design evolved from experiences with the ARPANET, NPLNET, EIN and CYCLADES networks and the work in IFIP WG6.1.
The physical layer defines electrical and physical specifications for devices. It also specifies modulated and baseband transmission.
Baseband is digital data in their raw form (in binary, the language understood by the computer in the form of 0s and 1s - 1001 1101 1010 0011). This allows very fast and reliable transmission over short distances; however, the media tend to make the bits interfere with each other, the range of baseband transmission is very limited. It becomes worse with increasing speed. Baseband technology is frequently used on LAN.
Typical technology: Ethernet cables
In telecommunications, modulation is the process of conveying a message signal, for example a digital bit stream or an analog audio signal, inside another signal that can be physically transmitted. The device that provides modulation of the baseband signal is called a modulator, and the device that provides demodulation of the modulated signal back to baseband is called a demodulator. Today, the modulator and demodulator are integrated into one device called Modem (modulator-demodulator). Frequently used on WAN, WLAN, WWAN.
Typical technology: WI-FI, ADSL, cable TV connection (CATV)
The data link layer provides the functional and procedural means to transfer data between network entities and to detect and possibly correct errors that may occur in the physical layer.
The network layer provides the functional and procedural means of transferring variable length data sequences from a source host on one network to a destination host on a different network using the IP address.
An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication. At present there are two versions of protocols in use – IPv4 and IPv6.
The transport layer provides transparent transfer of data between end users, providing reliable data transfer services to the upper layers. The Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP) of the Internet Protocol Suite are commonly categorized as layer-4 protocols within OSI.
Commonly united into one layer in simplified network models, its main purpose is to interact with applications, encrypting and establishing dedicated connections if necessary.
Latency, incorrectly called ping, is a value that measures how much time packets need to travel to their destination. It is measured in miliseconds (ms). The tool that measures latency is called ping, commonly using special ICMP packets which are smaller than standard data packets so they do not weight the network by their presence.
Capacity is a measure of transfer capacity of a network and is measured in bits per second (bps or b/s), today commonly Mbps or Mb/s. It shows us how many data units are transferred each second. At present, the average bandwidth is far higher than is necessary and it is not a limiting factor in most cases.
Broadcast is a special transmission that is not meant for a single device but is addressed to all devices in specific network. It is mostly used to automatically issue IP addresses to devices by a DHCP server and to create an ARP table that maps the network and speeds up the traffic.
DFC Heidenreichstein
The DFC Heidenreichstein is a woman´s football club from Heidenreichstein, Lower Austria, Austria. The club is playing in the Landesliga Niederösterreich, the third level in Austrian women´s soccer. Many years they were part of the ÖFB-Frauenliga, the highest level in Austrian women soccer.
The club was founded in 1981 as part of the FC Heidenreichstein. Soon the women department became independent. 1985 they played in the Damenliga Ost, which was the second level in women soccer. 1987 they were promoted for the first time in the ÖFB-Frauenliga (first level). 1990 they were relegated but came back in 1992. In 1993/94 they reached the third place in the ÖFB-Frauenliga which was the best place ever. In the 1992/93 season the club reached the final of the ÖFB-Ladies Cup. They lost 2:0 versus Union Kleinmünchen Linz. Also the 1994/95 cup final was lost versus Kleinmünchen. 1998 they were again relegated and played till 2009 in the second level. 2009 they were again relegated and at present they play in the Landesliga Niederösterreich,which is the third level.
as November 2011
GK-goalkeeper, DF-defence, MF- midfielder, FW-forward
Chuvash Wikipedia
The Chuvash Wikipedia () is the Chuvash language edition of Wikipedia. It was founded on November 22, 2004. Its 5,000th article was created in January 2007. On November 11, 2016, it passed 36,000 articles.
Rules in Chuvash Wikipedia are not as flexible in disputes as they are on English Wikipedia. Many things can be resolved through an . An arbitration committee can help with disagreements about things in articles, block users or stop certain users from editing articles on certain topics. Misuse of an administrator's privileges can also be easily appealed.
The Chuvash Wikipedia accepts fair use content. Many things are allowed. One thing that is not allowed is categorizing or listing people based on their ethnicity, religion or sexual orientation. Such categories are usually not allowed unless the category is relevant to the main activity of a person.
The Chuvash Wikipedia was created on November 22, 2004.
ChuvashTet
ChuvashTet (short for "Chuvash Internet"), () is the name Chuvash-speaking Internet users commonly use for the segment of the Web about the Chuvash people or Chuvashia. It includes webpages and websites in many languages.
Chuvash Internet users employ Latin and Cyrillic scripts.
Alikovo, Alikovsky District, Chuvash Republic
Alikovo (; , "Elĕk") is a locality (a "selo") and the administrative center of Alikovsky District of the Chuvash Republic, Russia. It is south of Cheboksary, on the Cheboksary—Krasnye Chetai and Cheboksary—Yadrin auto routes. Most of the 2,500 people who live there are Chuvash.
The Abashyrma River flows near Alikovo; and the closest village is Siner.
It was first mentioned in 1486.
The climate is moderately continental, with long cold winters and warm summers. Average January temperature is ; average July temperature is . The absolute recorded low was and the record high was . Annual precipitation is up to .
The facilities include a culture center, a theater, a library, a medical clinic, and stores. There is also a postal office, a stadium, a restaurant and cafés, and several gas stations. A market is open on Thursdays. There are two parks—central and one named after Andriyan Nikolayev.
Educational facilities include a middle school and a music school.
Cultural facilities include a museum, a people's theater, a people's ensemble, a veteran's orchestra, a school's brass band, and a chorus. International Chuvash music festival "Vir'yal shevlisem" ("Vir'yal's pancakes") is held during summers.