Analiza prometnog opterećenja nad komponentom HSS u mreži LTE

master's thesis

• Title (english): Traffic Load Analysis on the HSS Element in LTE Networks
• Author: Marin Vukšić
• Mentor: Željko Ilić (mentor)
• Committee member: Željko Ilić (predsjednik povjerenstva)
• Committee member: Gordan Šišul (član povjerenstva)
• Committee member: Krešimir Pripužić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 2015-07-01, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Computing
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering

Abstract

Pristupna mreža LTE (engl. Long Term Evolution) u odnosu na prethodne generacije pokretnih mreža uvodi poboljšanje u prijenosnoj brzini, smanjenju kašnjenja i kvaliteti usluge. Njena glavna karakteristika je ostvarivanje komunikacije bazirane u potpunosti na protokolu IP. Takvim se pristupom mrežnim korisnicima dopušta korištenje raznovrsnih multimedijskih usluga poput chatting aplikacije ili konferencijskog poziva. Arhitekturu LTE mreže možemo podijeliti na tri djela, pristupni (engl. Access), jezgreni EPC (engl. Evolved Packet Core) i upravljački (engl. Control). U upravljačkoj domeni nalazi se zasebna mreža IMS (engl. IP multimedia subsystem) koja pruža raznovrsne multimedijske usluge. Organizacija 3GPP (engl. 3rd Generation Partnership Project) nadležna je za standardizaciju sučelja u mrežama LTE i IMS. Nadalje, logika usluga implementira se na komponenti AS (engl. Application Server), a baza podataka u kojoj se nalaze pretplatnički podatci naziva se HSS (engl. Home Subscriber Server). Komunikacija između te dvije komponente ostvaruje se standardiziranim sučeljem Sh koje koristi signalizacijski protokol Diameter.
U ovome radu analizirane su karakteristike komponente HSS s obzirom na sljedeće modele prometnih opterećenja: Poissonovo, eksponencijalno, linearno te uniformno. Testiranje se vršilo s ciljem otkrivanja točke ispada komponente HSS. Također, u svrhu testiranja napravljena je programska potpora koja omogućava implementaciju odabranih modela opterećenja. Sve komponente IMS podsustava nalaze se u laboratoriju kompanije SIEMENS C.V.C. smještene u Zagrebu.
Razmatranjem dobivenih rezultata ustanovilo se da eksponencijalni model u najvišoj mjeri opterećuje komponentu HSS. Učestale promjene u frekvenciji slanja za posljedicu unose pogreške u odzivu protokola Diameter, kao i veliko vrijeme kašnjenja. U trenutku kada je HSS opterećen na ostalim sučeljima, ovaj problem može predstavljati kritičan slučaj. Rezultat takve okolnosti bilo bi smanjenje brzine obrade i povećanje broja neispravno obrađenih poruka.

Abstract (english)

The LTE network, in comparison with earlier generations of mobile networks, introduces faster data rates, lower latency and higher quality of service. The main feature of such architecture is to provide communication on common IP-based protocols. This approach allows network users to use various multimedia services such as chatting application or conference calls. The architecture of the LTE network is divided into three parts: the access, the EPC (Evolved Packet Core) and the control domain. The IMS (IP multimedia subsystem) is located in the control domain and provides various types of multimedia services to end users. The interconnections between network components in the LTE and IMS are standardized under the 3GPP (3rd generation partnership project) organization. Furthermore, the service logic is deployed in the AS (Application Server), and the HSS (Home Subscriber Server) is the master database that contains the subscriber related data. The communication between the HSS and the AS is realized via the standardized Sh interface. The signalization Diameter protocol is used to provide this communication.
This paper analyzes the characteristics of the HSS when it is overloaded with the following traffic models: Poisson, exponential, linear and uniform. Test cases were performed in order to determinate how much traffic load the HSS can handle. The task was also to develop a software that enables the implementation of desired traffic models. Furthermore, all IMS components are located at the Siemens CVC facility in Zagreb.
The results of testing show that the exponential model overloads the HSS in the highest rate. Frequent changes in the frequency of sending causes large delay times and adds Diameter errors. This problem can be critical when the HSS is also overloaded on other interfaces. The results would be lower processing speeds and a larger amount of errors.

• Keywords: LTE; EPC; IMS; 3GPP; AS; HSS; Protokol Diameter; Sh sučelje; Poissonov proces; eksponencijalna razdioba; linearno opterećenje; uniformna razdioba
• Keywords (english): LTE; EPC; IMS; 3GPP; AS; HSS; Diameter protocol; Sh interface; Poisson process; exponential distribution; linear traffic model; uniform distribution
• Language: english
• URN:NBN: urn:nbn:hr:168:398611
• Study programme: Title: Information and Communication Technology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka informacijske i komunikacijske tehnologije (magistar/magistra inženjer/inženjerka informacijske i komunikacijske tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2018-02-06 14:30:00