Pilsung Taegyun A Fathur Afif A Hari A Gary A Dhika April Mulya Yusuf Anin A Rizka B Dion Siska Mirel Hani Airita

Voice over Internet Protocol Course Number : TTH2A3 CLO : 2 Week : 7 ext

Circuit Switch vs. Packet Switch Dedicated Path Any Path Connection less Message Switch Packet Switch ex: data comm. at The Internet Connection Oriented Circuit Switch ex: voice comm. at PSTN Connection less, both parties (Sender and Receiver) need to agree first before communication happen Dedicated path, only 1 path (link) for 1 communication Q: How can we establish a voice communication using packet switch? A: Using VoIP, along with its signaling protocol SIP and H.323 Q: Why using packet switch? A: Better QoS, carrie any type of information, and accommodate future needs

Preface Voice uses analog signal, Packet Switch works on digital system. Thus, we need to transform analog voice into digital voice, using ADC (Analog to Digital Converter) Signaling Protocol uses TCP (Transfer Control Protocol Signaling port on TCP: H.323 uses port 1720 SIP (Session Initiation Protocol) uses port 5060

Sample Architecture IP Network PC PC IP Network PSTN Network Telepon PC Gateway Telepon Telepon IP Network Telepon Gateway Gateway Telepon PSTN Network PSTN Network Telepon Telepon

VoIP Protocol Session Initiation Protocol (SIP) H.323 Media Gateway Control Protocol (MGCP) Gateway Control Protocol (Megaco, H.248) Real-time Transport Protocol (RTP) Real-time Transport Control Protocol (RTCP) Secure Real-time Transport Protocol (SRTP) Session Description Protocol (SDP) Inter-Asterisk exchange (IAX) Jingle XMPP VoIP extensions Skype protocol Teamspeak The H.323 protocol was one of the first VoIP protocols that found widespread implementation for long-distance traffic, as well as local area network services. However, since the development of newer, less complex protocols such as MGCP and SIP, H.323 deployments are increasingly limited to carrying existing long-haul network traffic.

VoIP Elements User Agent any element that provides direct interaction with user to accommodate user s need Proxy a software that acts as VoIP server for user registration, authentication, and administration also known as Soft Switch Protocol Signaling for call setup, supervision, and clear down use TCP Under supervision, RTP transfer already-packetized voice using UDP, while RTCP using TCP CODEC (Coder Decoder) Used to transform analog voice into digital voice using certain characteristic, such as 64 kbps for G711 (H.323)

H.323

Preface H.323 is an ITU-T standard protocol to define real time multimedia communication via packet-based network, which has no SLG (Service Level Guarantee) H.323 components: Terminal or Customer End Point Gateway connects with different network (optional) Gatekeeper for call control Multipoint Control Unit (MCU) for conferencing

Arsitektur Protokol H.323 System Control/ User Interface Audio I/O Equipment Video I/O Equipment User Data Applications T.120 System Control H.245 Control Audio Codec G.711, G.722, G.723.x, G.728, G.729 Video Codec H.261 H.263 Session Layer and above H.225 Call Control H.225 RAS Control Receive Path H.225 Layer LAN Stack

SIP

Preface SIP is a IETF standard protocol for peer-to-peer signaling protocol Support HTTP and SMTP SIP components: User Agent: User Agent Client User Agent Server Server UAC SIP SERVER PROXY REDIRECT REGISTRAR LOCATION Signaling Messages Between User Agent And Server UAC UAS UAS SIP USER AGENT SIP USER AGENT

SIP Messages SIP has 2 types of messages: Request, sent from client to server, which contain type of operation Response, sent from server to client, which contain status information Six types of request messages: INVITE : shows an invitation to a user or service ACK : shows a confirmation from a previous invitation OPTION : used to query a server s capabilities BYE : sents by a user to terminate a communication CANCEL : used to cancel a previous request REGISTER : used to register a client in contact information

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