Internet Andra Oja What is Internet? The Internet is a global system of interconnected computer networks that use the standard Internet Protocol Suite (TCP/IP) to serve billions of users worldwide. It is a network of networks that consists of millions of private, public, academic, business, and government networks, of local to global scope, that are linked by a broad array of electronic, wireless and optical networking technologies. History of the Internet 1957:The United States Department of Defense formed a small agency called ARPA (Advanced Research Projects Agency) to develop military science and technology. 1961-1965:The Massachusetts Institute of Technology (MIT) started to research sharing information in small, phone-linked networks. ARPA is one of their main sponsors. 1966: The first ARPANET plan is unveiled by Larry Roberts of MIT. Packet switching techno
Tallinna Tehnikaülikool Raadio- ja sidetehnika instituut Projekt ainetes ,,IRT0030 Andmeside" ja ,,IRT0100 Kommunikatsioonivõrkude struktuurid ja teenused" teemal «VoIP teenus» Üliõpilane: Ruslan Karpovits Õpperühm: IATM Matrikli nr: 050829 Õppejõud: Avo Ots Tallinn 2008 Author's word This project is written to show some interesting aspects of working with VoIP (Voice over Internet Protocol) service. The project briefly describes the process of finding a solution for based VoIP problem and its realization.
oData transparency: In bit and byte oriented protocols, there is a problem if a control character (for ETX (End of Text) ·Same as ETB, only no more blocks will follow. ITB (End of > Differences with HDLC length of protocol field (1B or 2B) byte-oriented protocols) or the start-of-frame flag (for bit-oriented protocols) appears in the actual data. Intermediate Transmission Block) ·Same as ETB, except that the receiving statio Differs from HDLC because of multiaccess MAC that provides · Maximum payload length (default: 1500) This was not likely to happen in ASCII text, but is very likely with binary data. This is known as a data will not acknowledge after the error checking. EOT (End of Transmission) framing/error detection: · Type of CRC (2B or 4B) transparency problem an can be rectified with byte stuffing (for byte-orien
1. Üldine kommunikatsioonimudel Sõnumi allikas->saatja(allikast info)->edastussüsteem->vastuvõtja->sihtjaam [üheks näiteks võiks olla: Arvuti->modem->ÜKTV->modem->arvuti] sisendinfoAllikas(sisendandmed g(t))->edastaja e. transmitter(edasi saadetud signaal s(t))->edastussüsteem(saadud signaal r(t))->vastuvõtja(väljund andmed g'(t))- >lõppunkti saaväljund informatsioon m' 2. Kommunikatsioonisüsteemi ülesanne • mõistlik kasutamine/koormamine • liidestus(kokku ühendamine. Ntx: võrk+võrk, arvuti+võrk) • Signaalide genereerimine(edastamine)(signaalide ühest süsteemist teise üleviimine) • Sünkroniseerimine [andmeedastuse algust(saatja) ja lõppu(vastuvõtjat)] • Andmeside haldamine • Vigade avastamine ja parandamine(näiteks side mürarikkas keskkonnas) • Voojuhtimine (vastuvõtja saab pakette vastu võtta kindla kiirusega->on vaja kont
1 nädal. Sissejuhatus: arvuti ja info, ajaloo algus ... 1940 Meanings: Bit - the smallest unit of storage ( 1 binary digit) Byte - collection of 8 bits / is a unit of storage, 8 binary digits long Kilobyte - A unit of storage capacity (1024 bytes ) Megabyte - 1,048,576 bytes Gigabyte - 1,073,741,824 bytes Terabyte - 1 trillion bytes Algorithm - is a step by step method of solving a problem Program - is the expression of an algorithm in a programming language. ALGORITM - kindel eeskirjade jada, mis määrab üheselt ülesande lahenduskäigu. PROGRAMM - programmeerimiskeeles kirja pandud algoritm Greek logicians ( Kreeka loogikud ): Parmenides (5 sajand e.m.a.) : kasutas pikki loogilisi põhjendusi. Zenon Eleast (5 sajand e.m.a.) - apooriad/paradoksid Sofistid - Sokrates (470-399 e.m.a) - Platon (428/427 - 348/347 e.m.a): Aristoteles : väidete struktuur kui iseseisev uurimisobjekt Aristoteles Süllogismide näited: 1. eeldus: iga koer on imetaja. 2. eeldus: mõned nel
tutvu lausearvutuse keskkonnaga: http://logik.phl.univie.ac.at/~chris/gateway/formular-uk-zentral.html Millistel muutuja väärtustel on lause (Av(B&A))v(-A&(Cv(B&-C))) väär? Panna tuleb results only, 0 on väär 1 on õige Tutvu ajalooga saidis kuni II maailmasõda: http://www.maxmon.com/history.htm Loe läbi jutt ja proovi andmetega mängida: http://math.hws.edu/TMCM/java/DataReps/index.html Kahend süsteemi arvu(101101001) ->kümnend süsteemiks. Nr sisse ja bianarile punkt, ja vaatan base ten integeri kümnendarvudest annab Ecki appletis juuresoleva graafilise kujutise, teen kujundi ja vaatan base integeri mis vastab kahendsüsteemi arvule 1110001 ASCII tabelis? Nr sisse ja punkt bianari, vaatan ...teksti Kümnendsüsteemi arv 33 on kahendsüsteemis? 33 kirjutan ja Base-ten integer, vaatan bianary Loe läbi jutud Atbashi ja Caesari šifri (Caesar cipher) kohta: http://www.wikipedia.org 2 Tutvu ajalooga kuni 1970ndad: http://www.islandnet.com/~kpolsson/comphist/ 47-68 ingli
Facebook is a social networking service, which was launched in February 2004. It is owned and operated by Facebook Inc. In September 2012 Facebook had over billion active users and more than half of them were also using Facebook on a mobile device. Facebook's latest research shows that the most popular mobile device used for visiting m.facebook.com is iOS and by the popularity the second most used device is Android. Using Facebook on your mobile device raises the potential of your account getting stealed. It is so because most of the users don't use safe connection so all your data is available to other users on the same network. So the very first thing you should do is to use safe connection by adding to the end of this word ,,http://" (which you can find in the beginning of every webpage) an ,,s" so the address should be like ,,https://". The second thing you can do is that if you own the Wi-Fi access point then you should definately put a password to it because then others that don
Thesis “How is it possible to calculate IT security effectiveness?” Kristjan Kivimaa August 2022 1 Abstract In IT Security world, there is lack of available, reliable systems for measuring security levels/posture. They lack the range of quantitative measurements and easy and fast deployment, and potentially affects companies of all sizes. Readily available security standards provide qualitative security levels, but not quantitative results – that would be easily comparable. This deficiency makes it hard for companies to evaluate their security posture accurately. Absence of security metrics makes it complicated for customers to select the appropriate measures for particular security level needed. The research question for this research project is – “How is it possible to calculate IT security effectiveness?”. The aim of this research is to use this reference m
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