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THESIS PRESENTATION. Real Time Transport Protocol Processing in a Voice over IP Network. SUPERVISORS. Supervisor: Sven-Gustav Häggman Instructor: Tapio Savunen (Head of R&D, Nokia Networks). FACTS ABOUT THESIS.
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THESIS PRESENTATION Real Time Transport Protocol Processing in a Voice over IP Network
SUPERVISORS • Supervisor: Sven-Gustav Häggman • Instructor: Tapio Savunen(Head of R&D, Nokia Networks)
FACTS ABOUT THESIS • Work done in year 2001 (for Nokia Networks) with almost 6-8 months of full-time (and more) effort • Thesis report completed in 2005
FACTS ABOUT THESIS • A VoIP prototype system implemented • Workd done from implementation specifications to code development, module testing and successful demonstration of voice calls (individual and group).
PROTOTYPE ARCHITECTURE • Architecture consists of Control Plane server, User Plane server, and LAN client (simulating Nokia Mobile terminals. • Specifications for interface between Terminal, Control plane server, User plane server have been finalized in advance
PROTOTYPE ARCHITECTURE • Desktop PCs used with Linux OS (RedHat) as control plane and user plane servers • Laptop used as LAN client, with Wireless LAN in order to simulate ”air-interface” feeling
PROTOTYPE ARCHITECTURE • SIP protocol used as interface between User Terminal and Control Plane server (and between Control Plane servers). SIP works with Control Plane (identify and manage calls by contexts) • RTP protocol used as interface between User Terminal and User Plane server (and between User Plane servers). RTP works with User Plane (identify and manage calls by IP)
PROTOTYPE ARCHITECTURE • MEGACO protocol used as interface between Control Plane server and User Plane server • IPv4 Network
PROTOTYPE ARCHITECTURE MS = User Terminal U-UPF, G-UPF = User Plane Servers U-CPF, G-CPF = Control Plane Servers
POC CONCEPT • POC is Push to Talk (PTT) over Cellular • User must always press PTT (push-to-talk) button in order to talk • This prototype demonstrates POC-like service using VoIP
WHAT USER CAN DO WITH THIS PROTOTYPE? • User(s) can login into ”system” • User can make individual call to another user • User can make group call
WHAT USERS CAN DO WITH THIS PROTOTYPE? • User(s) can join to a predefined ”Talk-Group” • User can talk/listen in a ”Talk-Group” • User can log-off
USE CASE: USER LOGIN • MS sends SIP message to Control Plane with terminal information • Control Plane does basic checkings, remembers this data and sends MEGACO message to User Plane • User Plane memorizes terminal information and sends MEGACO reply to Control Plane • Control Plane sends SIP message back to MS informing successful login (if so!)
USE CASE: INDIVIDUAL CALL • MS (caller) sends RTP call setup (with callee info) message to User Plane • User Plane does necessary checking and informs control plane (MEGACO) • Caller’s Control plane contacts Callee’s Control plane (SIP) to find if callee is able to accept call
USE CASE: INDIVIDUAL CALL • After positive acknowledgment, Caller’s control plane informs Caller’s User-plane (MEGACO) • Caller’ user-plane sends RTP (positive acknowledgement) to MS • MS can now press PTT and start sending audio
THESIS WORK • There are 31 Use-cases implemented in this prototype • Actual Thesis Work = Implementing these 31 Use-cases for USER PLANE server (in addition to specifying such use cases + testing & bug-fixing + demonstration)
THESIS WORK • Other teams were involved in developing counter-part use-cases for Control Plane server, MS (LAN client) • MS Word used for documentation • Linux, C, C++, GNU Tools for SW development
WORK CONTINUES... • This prototype served as first ”proof of concept” to demonstrate POC-like service using VoIP • Full scale network is now running in some of major Mobile Operators worldwide who now provide PoC sevice to consumers