Protokol TCP na operacijskem sistemu Linux

JURIĆ, IGOR (author), Humar, Iztok (mentor)

Osrednja tema diplomskega dela je delovanje protokola TCP znotraj odprtokodnega sistema Linux ter primerjava različnih, izboljšanih algoritmov TCP. Diplomsko delo v teoretičnem delu predstavlja osnovno strukturo in delovanje operacijskega sistema Linux ter delovanje in opis algoritmov za preprečevanje zamašitev protokola TCP, kjer je skupna lastnost vseh algoritmov ta, da poizkušajo doseči nivo pretoka podatkov, pri katerem ne bo prihajalo do zamašitev omrežja. V praktičnem delu diplomskega dela so predstavljeni različni algoritmi protokola TCP, njihovo delovanje ter analiza delovanja znotraj operacijskega sistema Linux. S pomočjo namenskih orodij sem opravil meritve na omrežnem vmesniku, v katere so zajeti podatki o prepustnosti omrežja, hitrosti prilagajanja oddajnega okna in čas vrnitve. Meritve so bile izvedene na omrežju med dvema računalnikoma, ozko grlo pa je predstavljal omrežni usmerjevalnik. Rezultati meritev prikazujejo lastnosti algoritmov, kot so zamašitveno okno, prepustnost omrežja in čas vrnitve. Iz analize meritev je moč zaključiti, da sta za uporabo najprimernejša algoritma TCP Cubic in TCP Westwood, saj sta v primerjavi s TCP Reno in TCP Vegas pokazala največ odpornosti na ekstremne pogoje na omrežju in obenem dosegala visoke hitrosti prenosa. Izkazalo se je, da je TCP Vegas izjemno občutljiv na preusmeritev povezave in nikakor ni primeren za brezžične povezave.

• Language: Slovenian
• Keywords: TCP, Linux, Reno, Cubic, Vegas, Westwood, analiza algoritmov protokola TCP, kontrola zamašitev omrežja
• Work type: Undergraduate thesis
• Organization: FE - Faculty of Electrical Engineering
• Year: 2016
• PID: 20.500.12556/RUL-83104
• Publication date in RUL: 27.05.2016

Secondary language

• Language: English
• Title: TCP protocol in Linux operating system

Abstract

The main topic of the thesis is functioning of protocol TCP within open source operating system Linux and comparison between various enhanced TCP algorithms. The thesis in theoretical part presents basic structure and functioning of Linux operating system, functioning and introduction to congestion algorithms used in TCP protocol, which all have one thing is common, that is to try to achieve level of throughput with no congestions on the network. The practical part presents congestion algorithms, their way of functioning and analysis within Linux operating system. With the help of dedicated tools, I have completed measurments on network interface which consists data for throughput, adjusting congestion window and round-trip-time. Measurments were done between two computers, chokepoint was presented by network router. Results show algorithm characteristics like are congestion window, throughput and round trip time. From analysis we can conclude that TCP Cubic and TCP Westwood are most suitable for use as they reached high throughput. Compared to TCP Reno and TCP Vegas they both showed good resilience on extreme network conditions. TCP Vegas is extremely sensetive to connection rerouting and it's not suitable for wireless networks.

• Keywords: TCP, Linux, Reno, Cubic, Vegas, Westwood, analysis of TCP algorithms, congestion control