Interworking Between SIP/SDP and H.323

There are currently two standards for signaling and control of Internet telephone calls, namely ITU-T Recommendation H.323 and the IETF Session Initiation Protocol (SIP). We describe how an interworking function (IWF) can allow SIP user agents to call H.323 terminals and vice versa. Our solution addresses user registration, call sequence mapping and session description. We also describe and compare various approaches for multi-party conferencing and call transfer

Analyses of Protocol for Creating, Modifying and Terminating Sessions with One or More Participants

SIP je kratica za Session Initation Protocol. Protokol za pokretanje sesije je signalizacijski protokol koji se koristi za uspostavu, modifikaciju i raskidanje višemedijskih sesija temeljenih na IP protokolu. Zahvaljujući SIP-u moguće je uspostaviti i upravljati različitim višemedijskim komunikacijskim sesijama između dva ili više korisnika u obliku trenutnog poručivanja (instant messaging), glasovnih ili video poziva preko IP-a (Internet Protocol), razmjene podataka. SIP je baziran na internetskom protokolu HTTP (Hyper Text Transfer Protocol). SIP protokol obavlja mnoštvo funkcija u mreži kao što su: uspostava sesije, modifikacija sesije, prekid sesije, kontrola poziva, te nesesijski vezane funkcije kao što su pokretljivost, prijenos poruka, autentikacija. U ovome radu su prikazane i objašnjene značajke i funkcije SIP protokola primjenom UML (Unified Modeling Language) dijagrama koji nude skup dobro određenih grafičkih prikaza i omogućavaju dobro razumijevanje strukture i ponašanja nekog sustava. Za opis razmjene poruka između mrežnih entiteta najčešće se koriste dijagrami međudjelovanja jer prikazuju točno određeni vremenski slijed razmjene poruka između sudionika u sustavu. SIP specifikacija opisuje kako SIP protokol djeluje preko TCP (Transmission Control Protocol) i preko UDP (User Datagram Protocol). Oba transportna protokola imaju različite karakteristike i pružaju različitu uslugu za određene SIP aplikacije. TCP pruža pouzdanost u prijenosu dok UDP ne osigurava ni pouzdanost, niti osiguranu isporuku. Oba transportna protokola, UDP i TCP posjeduju određene prednosti i nedostatke, ali sadrže i određena ograničenja u vezi prijenosa signalizacijskih poruka.SIP is an abbreviation for Session Initiation Protocol. Session Initation Protocol is used to set up, modify, and terminate multimedia sessions over IP networks. Due to SIP it is possible to set up and maintain different multimedia communication sessions between two or more users in the form of instant messaging, voice over IP, multimedia distribution. SIP is based on internet protocol HTTP. SIP protocol carries out numerous functions on the net such as: session set- up, session modification, session termination, call control and nonsession functions such as mobility, message transfer, authentication. This work illustrates and explains the characteristics and functions of the SIP protocol using an UML diagram which offer an assembly of welldetermined graphic illustrations and enable a good understanding of the structure and behavior of a system. In order to explain the exchange of messages between network entities, interactional diagrams are used because they show a precisely definite time sequence of message exchange between participiants in the system. An SIP specification describes the way the SIP protocol acts through TCP and trough UDP. Both transport protocols have different characteristics and offer a specific SIP application with different services. TCP offers reliability in transferring, while UDP offers neither reliability not a secured message. Both transport protocols UDP and TCP posses certain advantages and disadvantages, but they also both have certain concerning the transfer of signalization

Analyses of Protocol for Creating, Modifying and Terminating Sessions with One or More Participants

SIP je kratica za Session Initation Protocol. Protokol za pokretanje sesije je signalizacijski protokol koji se koristi za uspostavu, modifikaciju i raskidanje višemedijskih sesija temeljenih na IP protokolu. Zahvaljujući SIP-u moguće je uspostaviti i upravljati različitim višemedijskim komunikacijskim sesijama između dva ili više korisnika u obliku trenutnog poručivanja (instant messaging), glasovnih ili video poziva preko IP-a (Internet Protocol), razmjene podataka. SIP je baziran na internetskom protokolu HTTP (Hyper Text Transfer Protocol). SIP protokol obavlja mnoštvo funkcija u mreži kao što su: uspostava sesije, modifikacija sesije, prekid sesije, kontrola poziva, te nesesijski vezane funkcije kao što su pokretljivost, prijenos poruka, autentikacija. U ovome radu su prikazane i objašnjene značajke i funkcije SIP protokola primjenom UML (Unified Modeling Language) dijagrama koji nude skup dobro određenih grafičkih prikaza i omogućavaju dobro razumijevanje strukture i ponašanja nekog sustava. Za opis razmjene poruka između mrežnih entiteta najčešće se koriste dijagrami međudjelovanja jer prikazuju točno određeni vremenski slijed razmjene poruka između sudionika u sustavu. SIP specifikacija opisuje kako SIP protokol djeluje preko TCP (Transmission Control Protocol) i preko UDP (User Datagram Protocol). Oba transportna protokola imaju različite karakteristike i pružaju različitu uslugu za određene SIP aplikacije. TCP pruža pouzdanost u prijenosu dok UDP ne osigurava ni pouzdanost, niti osiguranu isporuku. Oba transportna protokola, UDP i TCP posjeduju određene prednosti i nedostatke, ali sadrže i određena ograničenja u vezi prijenosa signalizacijskih poruka.SIP is an abbreviation for Session Initiation Protocol. Session Initation Protocol is used to set up, modify, and terminate multimedia sessions over IP networks. Due to SIP it is possible to set up and maintain different multimedia communication sessions between two or more users in the form of instant messaging, voice over IP, multimedia distribution. SIP is based on internet protocol HTTP. SIP protocol carries out numerous functions on the net such as: session set- up, session modification, session termination, call control and nonsession functions such as mobility, message transfer, authentication. This work illustrates and explains the characteristics and functions of the SIP protocol using an UML diagram which offer an assembly of welldetermined graphic illustrations and enable a good understanding of the structure and behavior of a system. In order to explain the exchange of messages between network entities, interactional diagrams are used because they show a precisely definite time sequence of message exchange between participiants in the system. An SIP specification describes the way the SIP protocol acts through TCP and trough UDP. Both transport protocols have different characteristics and offer a specific SIP application with different services. TCP offers reliability in transferring, while UDP offers neither reliability not a secured message. Both transport protocols UDP and TCP posses certain advantages and disadvantages, but they also both have certain concerning the transfer of signalization

Covert Channels in SIP for VoIP signalling

In this paper, we evaluate available steganographic techniques for SIP (Session Initiation Protocol) that can be used for creating covert channels during signaling phase of VoIP (Voice over IP) call. Apart from characterizing existing steganographic methods we provide new insights by introducing new techniques. We also estimate amount of data that can be transferred in signalling messages for typical IP telephony call.Comment: 8 pages, 4 figure

Security in Peer-to-Peer SIP VoIP

VoIP (Voice over Internet Protocol) is one of the fastest growing technologies in the world. It is used by people all over the world for communication. But with the growing popularity of internet, security is one of the biggest concerns. It is important that the intruders are not able to sniff the packets that are transmitted over the internet through VoIP. Session Initiation Protocol (SIP) is the most popular and commonly used protocol of VoIP. Now days, companies like Skype are using Peer-to-Peer SIP VoIP for faster and better performance. Through this project I am improving an already existing Peer-to-Peer SIP VoIP called SOSIMPLE P2P VoIP by adding confidentiality in the protocol with the help of public key cryptography